small buildings administration of the code

8/8/2019 Small Buildings Administration of the Code

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1 Administration Of The Code1.1 TitleThese provisions shall be known as the "Trinidad and Tobago Small Buildings Code" and shall referred toherein as "This code".

1.2 Scope1.2.1

The provisions in this code shall apply to the construction, alteration, movement, enlargement, repair,equipment, use occupancy, location, maintenance, removal and demolition of buildings, for single ormultiple family residential or general purpose use of not more than two stories in height and with a floorarea of three hundred square metres or less.1.2.2

This code is intended to provide minimum requirements to safeguard life, limb, health and public welfare.It calls for minimum requirements for building materials in common use and takes into consideration theneed for protection against wind and earthquake.1.2.3

Sufficient detail is provided to allow for the adequate preparation of plans for buildings under normalenvironmental conditions. Regulatory authorities would deal with approvals on the basis of adherence tothe requirements of this code.1.2.4

The builder/designer is advised to seek assistance from registered professionals in the design andconstruction of wind and earthquake resistant structures for buildings outside the scope of this codeand/or for special application or other than normal environmental conditions.

1.3 Application to build

1.3.1 GeneralA person wishing to erect a building or structure, or to carry out a building operation of a small building asdefined shall comply with the requirements of the Planning and Development of Land Act and also withthe requirements of this Code.1.3.2 Form of Application to BuildThree (3) sets of completed application forms and plans are to be provided. The plans shall include thefollowing:

(1) A location plan, showing the location of the lot sufficient to identify the site. Streets should be namedand lots numbered where applicable.


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(2) A site plan, normally at a scale of 1/100, 1/125, 1/200 or 1/250 showing the dimensions of the site andits relationship to abutting lots, roads, public utilities and buildings grades and elevations as described in(3); and the location of the proposed building in relationship to the site boundaries, which are to beidentified.(3) Existing and proposed contours and levels of the site are to be shown. The levels must show the

relationship of the lowest floor of the building with the levels of the adjoining street and with the knowndatum.(4) Building plans to include:I. Floor Plan to Metric Scale 1/50 and/or 1/100

To show:- room sizes and designations (all dimensions finish to finish including plaster)- positioning of doors and windows- materials used in construction- thickness of each wall (including plaster)II. Elevations and Sections to Metric Scale 1/50 and/or 1/100

To show:- roof heights (floor to ceiling) and pitch- height of floor above ground- positioning of doors and windows- materials used in constructionIII. Foundation Plan to Metric Scale 1/50 and/or 1/100

To show:- foundation layout- cross sections- materials used in constructionIV. Structural details to Metric Scale 1/50 and/or 1/100

To show:- details of beams


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- details of columns- details of slabs- details of floors- details of all walls- all reinforcement details- roof design and construction detailsV. PlumbingTo show:- water and waste isometrics- location of inspection boxes- location and details of grease traps- sizes and slopes of the pipes used in the sewer lines- details of septic tanks and soakawayVI. Site drainage

To show:- storm surface and roof water disposal- All drawings shall be individually numbered for ease of reference. Revisions shall carry revisionnumbers.- All drawings, specifications and accompanying data shall bear the name and address of the personresponsible for the preparation of the plans and documents.1.3.3 Approval in Part

a) Where approval of a portion of a building is desired prior to the issuance of a permit for the wholeproject, application shall be made for the complete buildings, and detailed plans for the which immediateapproval is desired shall be filed with the Chief Building Officer.

b) Should a permit be issued for a part of a building, the holder of such permit may proceed withconstruction without the assurance that the permit for the entire building will be granted. The granting ofsuch permit will depend on the approval of the application including all requirements.1.4 Approvals


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1.4.1

All construction plans specifications and associated reports required by these rules should conformed tothis code and shall be approved by the Chief Building Officer before construction commences.1.4.2

No construction shall commence until the Chief Building Officer has issued a permit or a written notice toproceed.1.5 Inspections1.5.1 Procedure

The Chief Building Officer is authorised to make the following inspections and either approve the portionof the works completed or shall notify the builder where such work does not meet with his approval:(i) SETTING OUT

(ii) FOUNDATIONS BEFORE CONCRETING

(iii) STRUCTURAL FRAME AND ROOF

(iv) RING BEAMS FORM WORK AND REINFORCEMENT

(v) PLUMBING

(vi) SITE DRAINAGE

(vii) FINAL INSPECTION(OCCUPANCY CERTIFICATE)

1.5.2

All inspections shall be carried out by persons authorised as Building Inspectors or by suitably qualifiedpersons approved by the Chief Building Officer and appointed to carry out such inspections.1.5.3

Work shall not be done on any part of a building or structure beyond the point indicated in eachsuccessive inspection without first obtaining the written approval of the Building Inspector. Such writtenapproval shall normally be given only after an inspection shall have been made of each successive stepin the construction as indicated by each of the foregoing inspections where appropriate.1.5.4

If circumstances warrant, the Chief Building Officer in his discretion may waive inspection but this doesnot absolve the owner and builder from the responsibility of any construction in contravention of thisCode.1.5.5

Reinforcing steel or structural framework of any part of any building shall not be covered or concealed in


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any manner whatsoever without first obtaining the approval of the Building Inspector or the SpecialInspector.1.6 Special inspectorWhen site conditions, size or complexity of the work warrants, the Chief Building Officer may impose a

condition on the permit requiring the owner to employ a Special Inspector for the inspection of thestructural framework, or any part thereof, and for the review of all plans relating to such work, as hereinrequired.(i) Buildings or structures or part thereof of unusual design or method of construction and with criticalstructural connections.(ii) Marine construction.(iii) Major foundations and/or pile driving.(v) Major site works.(vi) Drainage and waste disposal.

Such Special Inspector shall be a Listed Professional with the relevant experience. The Special Inspectorshall ensure compliance with this Code and shall submit regular progress reports and inspection reportsto the Chief Building Officer.

At the completion of the construction work or project, the Special Inspector shall submit a Certificate ofCompliance to the Chief Building Officer stating that the work was done in compliance with this Code andin accordance with the approved plan or plans. His duties shall end with the submission of suchcertificate.1.7 Completion certificatea) A new building shall not be occupied or a change made in occupancy or the nature of the use of abuilding or part of a building until after a Completion Certificate has been issued.

b) Upon completion of a building erected in accordance with approved plans and after final inspectionherein referred to, and - upon application, the Chief Building Officer shall issue a Certificate stating thenature of the occupancy permitted.

c) A temporary Completion Certificate may be issued for a portion or portions of a building, which maysafely be occupied prior to final completion of the building.

1.8 Compliancea) The issuance and granting of a permit shall not be deemed or construed to be a permit for, or anapproval of, any violation of this Code.

b) The issuance of a permit upon approval of plans and specifications, shall not prevent the Chief BuildingOfficer from thereafter requiring the correction of errors on such plans and specifications, or frompreventing building operations being carried on thereunder when in violation of this Code or anyRegulations applicable thereto.


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c) When during the construction of the work carried out under the permit, from issuance of permit toissuance of the Completion Certificate, the Chief Building Officer reasonably believes that approved plansare in violation of this Code, he shall notify the permit holder and the permit holder shall correct thedrawings or otherwise satisfy the Chief Building Officer that the design and/or working drawings are incompliance with this Code.

d) Compliance with this Code is the responsibility of the permit holder until the issuance of a CompletionCertificate; at which time it shall become the responsibility of the owner.

e) The permit granted for the construction of the work shall be available at the construction site duringnormal working hours for inspection by the Building Inspector.

1.9 Alternate materials and types of construction1.9.1 General

The provisions of this Code are not intended to prevent the use of types of construction or materials ormethods of designs as alternates to the standards herein set forth. Such alternates shall be offered forapproval and their consideration shall be as specified in this Section.1.9.2 StandardsThe types of Construction or materials or methods of design referred to in this Code shall be consideredas standards of quality and strength. New types of construction or materials or methods of design shallbe at least equal to these standards for the corresponding use intended.1.9.3 Application

a) Any person desiring to use types of construction or materials or methods of design not specificallymentioned in this Code shall file with the Chief Building Officer proof in support of claims that may bemade regarding the safety and sufficiency of such types of construction or materials or methods of designand request approval and permission for their use.

b) The Chief Building Officer shall approve such alternate types of construction or materials or methods ofdesign if it is clear that the standards of this Code are at least equalled. If, in the opinion of the ChiefBuilding Officer, the standards of this Code will not be satisfied by the requested alternate, he shall refuseapproval.


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3 General Construction3.1 Principle

3.1.1 Site preparation

3.1.1.1 Preliminary investigationBefore any construction work commences, it shall be determined whether planning permission and otherapprovals would be required from the competent (relevant) authorities. A preliminary inspection of the siteshall be undertaken so that preparation may be made for any problems or difficulties that may arise. This

time should also be used to plan how the site will be organised so that a logical layout may emerge.

3.1.1.2 Checklist for site conditionsCompletion of the checklist below will provide enough information about the site and its conditions topermit construction to begin.a) Has planning permission been obtained?b) Is easy access to the site available?c) Is there a surveyor's or topological drawing of the site?d) Have the location of all boundary markers been found?e) Are water, sewage disposal facilities and an electricity supply available on site?f) Take note of the general topography of site and other physical conditions likely to cause hazards.g) Is there evidence of termite infestation in the soil or trees?h) Will there be a need for the removal of large trees?i) Is the area normally subject to land slippage?

j) Is there adequate natural provision for the removal of storm water i.e. collection of water as a result ofheavy rains or flooding.k) Will construction endanger any of the public utility services?l) Determine the height of the water table if appropriate.m) Determine whether the soil is suitable for the construction of a soak-away pit.n) Determine the ground floor datum.o) Determine the depth of the foundation stratum.q) Select suitable areas for stockpiling aggregate.


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r) Select an area for the location of a concrete mixer or for the hand-mixing of concrete.s) Select location of a materials storage shed.t) Are their existing structures to be removed or altered?

Completion of the above checklist should highlight possible construction problems as well as therequirements of plant and materials. Where foundation problems are evident it is recommended that anengineer or any other appropriate professional be consulted.

3.1.2 Site clearance3.1.2.1Care should be taken to preserve any trees on the site. Where it is necessary to remove any trees,special care shall be taken to remove, totally, all roots and stumps of the felled trees as well as any of theother remains from the site.

NOTE There may be statutory limitations on the extent to which large trees may be removed.3.1.2.2The area where the building will be situated shall be stripped of topsoil. This material should be stockpiled in a suitable area for later use during landscaping.3.1.3 Material storage3.1.3.1

Areas shall be allocated on the cleared site for the storage of materials. Coarse and fine aggregate for the

mixing of concrete and mortar shall be placed in separate heaps in a location near to the concrete mixeror concrete mixing area.

3.1.3.2

Cement, nails and finished materials (groove ply, PVC pipe, galvanised sheeting etc.) requiring protectedstorage shall be stored in a shed, which is weather tight and has a wooden floor raised not less than four

inches off the ground.3.1.3.3Reinforcement steel shall be stacked off the ground to reduce corrosion.

3.1.4 Batter boards

The building shall be properly set out on the site according to the building plan. Batter boards, which arehorizontal boards parallel to the sides of the building and supported by vertical boards driven into theground shall be erected in convenient locations near the four corners of the building, and to these boardsshould be transferred the building lines and levels for the project.3.1.4.1


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The floor level is usually marked on the batter boards and used as a permanent reference. All wall linesand levels shall be referred to these boards. Periodic checks shall be made to ensure that these boardshave not been shifted from their intended positions.3.1.5Driveways and paving3.1.5.1The driveways and paving dealt with in this section are those suitable for use as driveways and parking

areas for private cars and light goods vehicles only. Driveways shall be not less than 3m wide.3.1.5.2The choice of flexible (asphalt) or rigid (concrete) paving is largely influenced by the soil conditions at thesite and the cost of driveway. Gravel driveways and paving are acceptable if adequate drainage isavailable and if the gravel or crushed rock is reasonably hard, free from clay, and would not be easily

crushed by the light traffic. Adequate provision for drainage shall be made3.1.5.3Where firm soils or rocks are present, any type of paving previously mentioned may be used. Where soft

soils are present gravel or a flexible paving is recommended.3.1.5.4For all kinds of paving the topsoil shall be removed and replaced by a minimum of 150 mm of compacted,

granular material.3.1.5.5For rigid paving, a concrete slab with a minimum thickness of 100 mm is required, reinforced by welded

wire mesh of minimum 100 mm2

/m wide in both directions, placed 25 mm below the slab surface.Construction joint shall be created every 5 m.Note: A98, A142 and 150x150X4.5 BRC are acceptable.3.1.5.6For flexible paving a minimum thickness of 50 mm of asphalt (cold or hot mix) shall be applied andcompacted by roller on an approved and adequate sub base.

3.1.6 Earth works3.1.6.1 Site topography

3.1.6.1.1The natural topography of the land should be maintained and any excavation or back filling that must becarried out (and deemed as necessary) should be kept to a minimum. This is necessary to maintain the

natural vegetation, prevent landslides and flooding and preserve in general the natural environment.3.1.6.1.2


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It is essential therefore that buildings should be constructed in such a manner to compliment the natural

topography of the site and not vice-versa.3.1.6.2 Soil conditions3.1.6.2.1The characteristics of the site soil conditions shall be ascertained. If necessary, compaction shall be

carried out in order to improve the bearing value of the soil.3.1.6.2.2Where expansive clay is encountered or where problem conditions are present, professional advice shallbe sought before planning the foundation.

3.1.6.3.1

Excavations for foundations shall be carried out along the building lines to the depth of the foundationstratum identified as suitable.3.1.6.3.2

Excavations not exceeding 1.5 m in depth may generally be without planking and strutting, which is asystem of braced timber walls erected against the faces of the excavation to prevent collapse. Forexcavations exceeding 1.5 m the extent of planking and strutting necessary shall be determined by thenature of the soil and the location of the water table.

3.1.6.3.3Where collapse of the side of excavation is anticipated, all excavation in excess of 1.5 m in depth shall be

planked and strutted.3.1.6.3.4Where the foundation is in rock, it shall be excavated at least 50 mm to provide a key for the foundations.

3.1.6.3.5The bottom of all excavations shall be level and firm. Where loose materials are encountered, foundation

bottoms shall be compacted by ramming.3.1.6.3.6

Where excavations have been carried beyond their generally required depth, either by accident or design,the deep areas shall be back filled with compacted, adequate material or with Grade E concrete (seetable B-1).

3.1.6.4 Back filling3.1.6.4.1Back filling shall not be carried out in dry rivers, natural drains, where water flows after heavy rains andalong thalwegs (lowest areas in valleys).


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3.1.6.4.2Back filling around foundation walls and under floor slabs shall be carried out using only suitable, selectedmaterials. Unless the floor slab is reinforced to act as a suspended slab, the depth of fill shall not exceed1 m.

3.1.6.4.3

Suitable fill material may be brought to the site or obtained from excavated material, provided always thatsuch material is free of substantial amounts of clay or organic matter.

3.1.6.4.4All backfill shall be well compacted in layers not exceeding 150 mm in thickness where compaction is byhand. Where mechanical compaction equipment is used, the thickness of layers may be increased to 225mm.

3.1.6.4.5

Where back filling under floor slabs on grade has been effected using hard core, a 50 mm layer of sandshall be applied to the top of the compacted hard core to protect damp proof membranes from puncture.

3.1.7 Earthquake considerations

3.1.7.1 Earthquake resistant construction3.1.7.1.1GeneralTrinidad and Tobago is in an earthquake zone and has experienced varying degrees of damage due toearthquakes. It is therefore essential that buildings are designed and constructed so that they have someresistance to the shaking or lateral forces produced by earthquakes.

3.1.7.1.2 Effect of soil type

3.1.7.1.2.1

The type of soil at the site may have a significant effect upon the resistance of the building to anearthquake. However for buildings within the scope of this code the effect of the soil type is not sosignificant provided that the building is not constructed on loose saturated sands, which may liquefyduring an earthquake and cause collapse of the building.

3.1.7.1.2.2The earthquake may also, due to shaking of the ground, compact loose sand or fill material, and if abuilding is constructed on such material, the building will be damaged.

3.1.7.1.3 Effect of high seas

Buildings on coastal areas may suffer due to high waves produced by earthquakes, and therefore thesiting of the building in relation to the sea level needs to be considered. Professional advice shalltherefore be sought in such cases.

3.1.7.1.4Building shape3.1.7.1.4.1


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The success with which a building survives an earthquake is greatly affected by its shape in plan, the waythe building is tied together and the quality of construction.

3.1.7.1.4.2

Most buildings with a simple rectangular shape with no projections (or only short projections) perform wellunder earthquake conditions provided the construction is adequate.

3.1.7.1.4.3Long narrow buildings should be avoided by limiting the length to three times the width. If the buildingmust be longer, then it should be divided into separate blocks with adequate separation. Figure A1-1illustrates desirable and undesirable plan shapes.

3.1.7.1.4.4Rectangular buildings with well inter-connected cross walls are inherently strong and therefore desirable.


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Fig A1-1 Plan of building proportion


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Fig A1-2 Recommended location of wall opening


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Fig A1-3 Recommended location of wall opening for tow storey building


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3.1.7.1.5 Appendages

Where buildings have decorative or functional additions or appendages such as window hoods, parapetsand wall panels etc. extreme care must be taken to ensure that they are securely fixed, since many ofsuch items tend to fall easily and may cause damage during an earthquake.

3.1.7.2 Rules for the construction of earthquake resistant buildings

It is recommended that the following rules be followed for the construction of buildings:

3.1.7.2.1 Masonry buildings

An important factor contributing to the earthquake resistance of masonry buildings is the detailing andplacing of steel reinforcement. A registered professional should undertake the design of a reinforcedconcrete frame building. The reinforcing guide given in this section therefore must only be used for simplesingle storey buildings constructed of approved quality masonry blocks. For the minimum quantities ofreinforcing steel to be used refer to Clause Vertical Structures.

3.1.7.2.2 Timber buildingsThere are two additional areas of concern with respect to timber buildings:

All corners and intersections must be adequately braced.Earthquake and hurricane forces tend to remove timber buildings from their supports by shaking.Because of this sills shall be securely fastened to foundations.3.1.7.2.3 Steel buildingsThe natural ductility of steel protects the frame from severe damage. However, in many cases masonryblock walls are used and the precautions already listed for these walls will apply. The wall reinforcementmust now be anchored by welding to the steel columns and beams, or the steel frame encased in

concrete in which case the wall reinforcement can be tied into the concrete cage encasing the steelframe.

3.1.7.3 Location of openings3.1.7.3.1The location and size of openings in walls have a significant effect upon the strength of a wall and itsability to resist earthquake forces.

3.1.7.3.2Openings shall be located away from a corner by a clear distance of at least 1/4 of the height of the

opening. It is recommended that the minimum distance be 400 mm.

3.1.7.3.3The total length of the openings should not exceed 1/2 the length of the wall between consecutive crosswalls (see figure A1-2).

3.1.7.3.4


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The horizontal distance between two openings should not be less than 1/2 the height of the shorteropening (see figure A1-2).

3.1.7.3.5For two storey buildings, the vertical distance from an opening to one directly above it shall not be less

than 600mm, nor shall it be less than one half the width of the smaller opening.


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3.1.8Hurricane considerations

3.1.8.1Hurricane resistant construction3.1.8.1.1 General

3.1.8.1.1.1

It is very important in Trinidad and Tobago to be ever conscious of the fact that the region lies in thehurricane belt. Because of this, hurricane resistant construction principles must be adhered to if safebuildings are to be erected. This section gives general principles for safe hurricane resistant design, andit is recommended that the details shown in these guidelines must be adhered in order to ensure safeconstruction.3.1.8.1.1.2For the buildings within the scope of this document the areas most vulnerable to hurricane forces are theroofs, windows, walls and appendages.

3.1.8.1.1.3The underlying objective of hurricane resistant construction is to produce a building that will not collapseduring a hurricane. The building must be standing and its occupants should be safe.

3.1.8.2 Rules for the construction of hurricane resistant buildings

3.1.8.2.1Building site3.1.8.2.1.1Buildings sited in exposed areas (e.g. on the brow of a hill or near coastal areas) are most vulnerable,

while those sheltered by natural topography are less vulnerable. Buildings sited in gullies or riverbeds arevery vulnerable as they are subject to severe damage by floods caused by the heavy rains, which oftenaccompany a hurricane.3.1.8.2.1.2In siting the building, therefore, steep slopes and edge of cliffs should be avoided, as well as otherconditions such as steep sided valleys where exceptionally high wind speeds are found.

3.1.8.2.1.3Tie beams should be constructed to reduce the untied height of the columns to a maximum of 3 metersas shown in figure A1-6. It is advisable to seek professional assistance for such construction, unless

otherwise designed for larger columns.

3.1.8.2.2 Timber buildings.3.1.8.2.2.1Because of the relatively light nature of a timber building, extra precautions shall be taken to preventuplift. Care must therefore be taken to ensure that the entire structure is securely fastened to thefoundations.


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3.1.8.2.2.2The spaces between the supporting columns or piers may be filled in to reduce the uplift forces (seefigure A1-6).

3.1.8.2.2.3As far as timber walls are concerned, in addition to bracing corners in both directions, diagonal braces orsteel straps must be installed at the level of the top plate to provide rigidity of the corners at that level (seefigures A1-7 and A1-8).


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Fig A1-4 Typical roof gable wall arrangement


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Fig A1-5 Recommended method of construction on sloping sites


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Fig A1-6 In-fill panel between timber building supports


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Fig A1-8 Timber framing for wallFig A1-9 Rafter/wall plate connections


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Fig A1-10 Rafter/ ring beam connections


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Fig A1-11 Wall plate connections and hurricane ties


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3.1.8.2.3 Steel buildings

The principles for the design and construction of hurricane resistant steel buildings are:

3.1.8.2.3.1Ensure that there are adequate numbers and sizes of foundation holding down bolts, and that they are allin place and properly fixed.

3.1.8.2.3.2Ensure that there is adequate lateral support provided by cross bracing or horizontal ties or by cast inplace concrete or masonry walls.

3.1.8.2.3.3Where concrete walls or concrete masonry is used, the connections between the steel frames and thewalls shall be provided.

3.1.8.2.3.4Ensure that the fabricator's recommendations with regards to the construction of the roof and roofcovering are followed.

3.1.9 Roofs.

3.1.9.1

Roofs with pitch between 0 and 20 (or a slope between 0 % and 36 %) are more vulnerable to upliftforces. It is recommended that roofs be constructed with a pitch between 20 and 40 (or a slope between36 % and 84 %).

3.1.9.2The aptitude to reduce uplift forces is affected by the shape of the roof in the following order from themost effective to the least effective:

a) Hip roofb) Gablec) Shed

3.1.9.3

Attention should be given to the location of fixings used for the roof cladding. It is necessary to provideadditional fixings at the roof edges and ridge, since high-localised pressures are produced in theselocations.

3.1.9.4Roof overhangs also experience high local pressures and, where possible, these should be kept to aminimum or adequately strengthened.


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3.1.9.5Where buildings have covered patios or verandas, their roofs may be separate structures rather thanextensions of the main building roof. A patio or veranda roof may be lost without endangering the safetyof the main roof.

3.1.9.6

The main roof must be securely fixed to the ring beam and ridge beams and details for achieving this areshown in figures A1-9, and A1-10 and A1-11.

3.1.10 Windows and doorsSpecial attention must be paid to the installation of doors and windows, since the loss of a door or windowduring a hurricane will greatly alter the internal pressure of the building, thus adversely affecting itssafety. For this reason, glazed windows and doors may be fitted with shutters.

Fig A2-1a Basic 1 or 2 level house type

Fig A2-1b Mixed 1 or 2 level house type


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Fig A2-1c 1 or 2 level house, other combination


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3 General Construction3.2 Design criteria3.2.1 Conventional design

Buildings and structures, and all parts thereof, shall be constructed to support safely all loads, including

dead loads.

Where different construction methods and structural materials are used for various portions of a building,

the applicable requirements of this part for each portion shall apply.

3.2.1.1 Conventional building

Conventional construction shall be considered as building with acceptable shape of the figures A2-1 (a

to c) 1 and 2 level house type.All conventional construction shall be designed in accordance with thiscode.3.2.1.2 Irregular buildingIrregular buildings shall have an engineered lateral-force resisting system designed in accordance with

accepted engineering practice.A building shall be considered to be irregular when one or more of the following conditions occur:a) When exterior shear panels or reinforced frame is not in one plane vertically from the foundation to the

uppermost story in which they are required. (See Framed structure)b) When a section of floor or roof is not laterally supported by shear panel or reinforced frame on all

edges.c) When an opening in a floor or roof exceeds the lesser of 3.60m or 50% of the least floors or roofs

dimension.d) When portions of a floor level are vertically offset.e) When shear panel or reinforced frame is do not occur in two perpendicular directions.f) When shear panel or reinforced frame are constructed of dissimilar bracing systems on any one-story

level above grade.3.2.1.3 Limit of this code.When a building of otherwise conventional constructioncontains structural elements, which exceed the limits of this code, those elements shall be designed in

accordance with accepted engineering practice.


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Fig A2-2 Trinidad & Tobago winds


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3.2.2 Engineered design.

3.2.2.1 General

Buildings shall be constructed in accordance with the provisions of this code as limited by the provisions

of this section.

3.2.2.2 Wind design.

The requirements in this document are based on design wind speed over open water at equivalentelevation of 10m average over 10 minutes with a recurrence of one in 50 year. (See figure A2-2 Trinidadand Tobago Winds)

Table 1 Design pressure for windsDesign pressure Trinidad

CentralTrinidadCoastal

Tobago

Basic wind speedKm/hr 72 92 101

Wall (horizontal load)

kN/m2 0.70 0.90 1.00

Roof (uplift) kN

/m

21.00

1.30

1.45

3.2.2.3 Seismic design.

All buildings shall be constructed in accordance with the provisions of this section.

3.2.2.3.1 Seismic design category.3.2.2.3.1.1 Ground accelerationThe requirements in this document are based on maximum ground acceleration associated with 10%

probability of occurrence in 50 years. For Trinidad & Tobago 0.3 g (g refers to the gravity and g =9.81m/s

2)

3.2.2.3.1.2 Amplification factorWhere the soil is 100% saturated (low land, reclaimed land, etc.) an amplification factor of 2 shall be

applied to the ground acceleration. See calculation for shear load.


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3.2.2.3.1.3 Soil liquefactionTo prevent any soil liquefaction on the same type of land than above a special attention shall be carried

out with an engineer specialist for the choice of the appropriate type of foundation. See calculation for

shear load.


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3.2.2.3.2 Weights of applied finishesDead load finishes shall not exceed 1 kN/m2 for roofs or 0.5 kN/m2for floors. Dead load finishes for walls above grade shall not exceed:a- light-frame walls 0.75 kN/m2 forexterior0.50 kN/m2 for interiorb- masonry walls.2.50 kN/m2 for 150mm thick masonry wall.3.80 kN/m2for 200 mm thick masonry wall.c- concrete walls.4.10 kN/m2 for 150 mm thick concrete walls.3.2.2.3.3 Height limitations. The design applied to any construction is limited to two stories with a

maximum of9m to the top of the building.

3.2.2.4 Flood plain construction.

Buildings and structures constructed in flood prone areas as established in Fig. A2-1 shall be designed

and constructed in accordance with Clause Flood resistant construction and Clause Coastal high hazard

areas of Part "Minimal requirements".3.2.3 Dead load.

The actual weights of materials and construction shall be used for determining dead load with

consideration for the dead load of fixed service equipment.3.2.4 Live load.

The minimum uniformly distributed live load shall be as provided in Table 2.Table 2 Minimum uniformly distributed live loads

Use Live loads (kN/m2)Exterior balconies 5Domestic floor / All rooms, stairs and corridors 1.5Office floor 2.5Small industrial and storage 5Use Horizontal loads (kN/m)Guard rails and handrails 1

FigA

2-3 Trinidad flood prone areas

3.2.5 Roof load

Roof shall be designed for the live load indicated in Table 3.

Table 3 Minimum roof live loads (kN/m2)


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Roof slope Tributary loaded area for any structural members

Area (m2)0 to 20m2 20 to 55m2 over 55m2

Flat or rise less than (20) 33% slope 1 0.75 0.6Rise (20) 33% to (45) 100% 0.75 0.7 0.6Rise greater than (45) 100% 0.6 0.6 0.6


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3.2.6 Lateral load design

3.2.6.1


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PreambleWind and earthquake introduce horizontal loads in the superstructure that are transferred to thefoundation. We have to consider 2 steps:a) Transfer of the horizontal load from- wind to vertical wall androof- acceleration of mass located everywhere in the superstructureto the appropriated wall or framedstructure.b) Transfer of the load from the top to the bottom of the wall or superstructure and thefoundation.According to this code- horizontal transfer is done by horizontal diaphragm or horizontalbeam- vertical transfer is one by shear panel, cross, or framed structure 3.2.6.2 DiaphragmFloor, roofor ceiling assemblies may be constructed with the necessary stiffness and load path continuity todistribute lateral loads (wind and earthquake) to lateral support subsystems. In this role, floor, roof orceiling surface act as horizontal beams (also called a diaphragm) spanning lateral supports points.Use offloor, roof or ceiling assembly, as a diaphragm requires both strength and stiffness properties anddevelopment of connections to transfer the diaphragm force.


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Fig B6-2 Shear panel - Horizontal core blocks

3.2.6.3 Shear panel3.2.6.3.1

Concrete wallA shear panel (see figures B-6-1 and B-6-2 Shear panel) is a portion or section of a 150mm


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exterior wall that performs the function of resisting lateral earthquake or wind forces.3.2.6.3.2 TimberSee paragraph "Wall bracing".3.2.7 Load factors.

All structures shall resist combined loads as follows;3.2.7.1

Gravity1.40 D + 1.70 L3.2.7.2Earthquake a) 0.75 (1.40 D + 1.70 L +/- 1.87 E)andb) 0.90 D +/- 1.43 E 3.2.7.2.1Shear load calculationA simplified formula, for this code is V = 0.05 x S x W total shear in kN Whereas :The 0.05 coefficientintegrated the Z = ground acceleration, C = amplification factor due to structure frequency, I = Importancefactor =1 in this code and Rw = Ductility factor related with respect to the column design reinforcementused in the normal practice formula. S = site factorS = 1 For good soil (rock, gravel)S = 1.2 For softermaterial (clay, fill )S = 1.5 For deep alluvial depositsS = 2.5 maximum for reclaimed land and saturatedsoils (due to the amplification factor) W = total load in kN3.2.7.3

Wind 1.40 D + 1.70 L + 1.75 W Note:D = dead loadL = live loadE = earthquake loadW = wind load3.2.8 Deflection.

The allowed deflection of any structural member under the live load shall not exceed the following valuesin Table 4 Table 4 Maximum deflection authorised.Rafters and purlins L/180Interior walls and partitions H/180Floors and ceilings L/360All others structural members L/240NOTES:L = span length H = span height


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3 General Construction3.3 Minimal Requirements

3.3.1 Location on lot

3.3.1.1 Exterior walls.

Exterior walls with a fire separation distance less than 1.25m shall have not less than a one-hour fire-

resistive rating. The one-hour fire resistive rating of exterior walls with a fire separation distance less than

1.25m shall be rated for interior and exterior exposure. Projections beyond the exterior wall shall not

extend more than 300mm into the fire separation distance. Projections extending into the fire separation

distance shall have not less than one-hour fire-resistive construction on the underside. The above

provisions shall not apply to walls, which are perpendicular to the line used to determine the fire

separation distance.

3.3.1.2 Openings.

Openings shall not be permitted in the exterior wall of a dwelling with a fire separation distance less than1.25m. This distance shall be measured perpendicular to the vertical plane of the opening.

3.3.2 Light3.3.2.1 Habitable rooms.All habitable rooms shall be provided with an area to allow natural light to enter not less than 10 percentof the floor area of such rooms.

3.3.2.2 Adjoining rooms.

For purpose of determining requirements of light, any room shall be considered as a portion of anadjoining room when at least one-half of the area of the common wall is open and unobstructed andprovides an opening of not less than 10% of the floor area of the interior room but not less than 2.50m

2.

3.3.2.3 Bathrooms.

Bathrooms, water closet compartments and other similar rooms shall be provided with an area to allownatural light to enter not less than 0.25m

2.

3.3.2.4 Stairway illumination.

All interior and exterior stairways shall be provided with a means to illuminate the stairs, including thelandings and treads.

Interior stairs shall be provided with an artificial light source located in the immediate vicinity of eachlanding at the top and bottom of the stairs.

Exterior stairs shall be provided with an artificial light source located in the immediate vicinity of the toplanding of the stairs.


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3.3.3 Ventilation

3.3.3.1 Natural ventilation3.3.3.1.1 Habitable rooms.Natural ventilation shall be provided in all habitable room through windows, louvres or other naturalopenings through the external wall to the outdoor air.

The minimum area of ventilation shall be not less than 15 percent of the floor area of such rooms.

3.3.3.1.2 Adjoining rooms.

For purpose of determining ventilation requirements, any room shall be considered as a portion of anadjoining room when at least one-half of the area of the common wall is open and unobstructed andprovides an opening of not less than 15% of the floor area of the interior room but not less than 2.50m

2.

3.3.3.1.3 Bathrooms.

Bathrooms, water closet compartments and other similar rooms shall be provided with a ventilation area notless than 0.25m

2.

3.3.3.2 Mechanical ventilation

3.3.3.2.1 Habitable rooms.All habitable rooms shall be provided with the minimum ventilation rates of 30m

3/hr for continuous ventilation

for every 12m2

of the floor area or part of such rooms.

This ventilation shall be through windows, doors or other natural openings through the external wall from the

outdoor air through a special 30m3/hr-air regulator.

3.3.3.2.2 Kitchen and bathroomsAll the air introduced into the house through the habitable rooms must be extracted in the rooms e.g.kitchen, bathroom, toilet, washing room and other similar rooms have to be maintained in depression tocreate an air flow through the house.

The minimum exhaust airflow for each room is as follows

Kitchen 120 m3/hr

Bathroom 60 m3

/hr

Shower 60 m3/hr

Toilet (WC) 30 m3/hr

Washing room and store room 30 m3/hr


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This ventilation air shall be exhausted permanently and directly outside.

3.3.3.2.3 Internal doorsAll internal doors have to be provided with air passages not less than 150 cm

2.

Note: These passages can be provided with a bottom gap of 2 or 2.5cm under the door.

3.2.3.2.4 Minimum global ventilationFor each house or apartment the minimum ventilation rate is one volume of the habitable part of the houseper hour.

3.3.4 Minimum room areas3.3.4.1 Minimum area.

Every dwelling unit shall have at least one habitable room (living, sleeping, eating or cooking room), which

shall be not less than 12m2 of floor area.

3.3.4.2 Other rooms.

Other habitable rooms shall have a gross area of not less than 7.50m2.

3.3.4.3 Exception:

Kitchennot less than 5m

2

Bathroom not less than 3m2and not less than 2m2 for the second oneShower not less than 1.5m2Toilet (WC) not less than 1m2See figure A3-1 Minimum room sizes, A3-2 Typical furniture arrangement and A3-3 Typical arrangement

7.5m2

room.


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Fig A3-1 Minimum room sizes


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Fig A3-2 Typical furniture arrangement


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Fig A3-3 Typical furniture arrangement - 7.5 m

2room

Habitable rooms shall not be less than 2.50m in any horizontal dimension.


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Exception: minimumKitchen 1.80m wide.Bathroom 1.40m wide.Shower 0.90m wide.Toilet (WC) 0.75m wide and 1.25m long.Corridor 1.00m wide.Stair 1.00m wide.

3.3.4.5 Height effect on room area.

Portions of a room with a sloping ceiling measuring less than 1.50m or a furred ceiling measuring less than2.15m from the finished floor to the finished ceiling shall not be considered as contributing to the minimumrequired habitable area for that room.

3.3.5 Ceiling height3.3.5.1 Minimum height.3.3.5.1.1 Habitable roomsHabitable rooms (living, sleeping, eating or cooking room) and basement shall have a ceiling height of notless than 2.40m. See figures A3-4 Habitable room area3.3.5.1.2 Other roomsOther rooms e.g. corridors, bathrooms, toilet rooms and laundry shall have a ceilingheight of not less than 2.15m.

3.3.5.1.3 MeasurementThe required height shall be measured from the finish floor to the lowest projection from the ceiling.

3.3.6 Minimum passageThe minimum passage for the access to the dwelling and each room shall be as follows

3.3.6.1 Main entranceAlmost one access door from outside shall be not less than 900mm wide and 2000mm high.3.3.6.2 Habitable rooms and secondary rooms e.g. Store and laundryAll passage for the access from another room or from the corridor shall be not less than 7 85mm wide and

2000mm high


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3.3.6.3 Other rooms e.g. Bathroom and toiletAll passage for the access from another room or from the corridor shall be not less than 6 85mm wide and

2000mm high


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Fig A3-4 Habitable room area


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3.3.7 Sanitation3.3.7.1 Toilet facilities.

Every dwelling unit shall be provided with a water closet or privy, lavatory basin, and a bathtub or shower.

3.3.7.2 Kitchen.

Each dwelling unit shall be provided with a kitchen area and every kitchen area shall be provided with asink.

3.3.7.3 Sewage disposal.

All plumbing fixtures shall be connected to a sanitary sewer or to an approved private sewage disposal

system.3.3.7.3.1 Septic tank

The capacity of the septic tank shall be calculated on the basis of 500 litres of sewage per person, full time

user.The minimum capacity is 2,500 litresThe water table must be a minimum of 1 metre deepest than the septic tank. See figure A3-11 for 2500 litres and A3-12 for 3200 litres septic tank.See also "Code of Practice for the Design and Construction of Septic Tanks and Associated Secondary

Treatment and Disposal System" TTS 16 80 400: 1986.Note: The above figures complied with this code.3.3.7.3.2 Soak-away pit

See figure A3-13The water table must be a minimum of 1 metre deepest than the soak-away. 3.3.7.3.3Draining trench

Where is impossible to make a soak-away, a draining trench shall be used See figure A3-143.3.7.4 Water supply to fixtures. All plumbing fixtures shall be connected to an approved water supply.

Kitchen sinks, lavatory basins, bathtubs, showers, bidets, laundry tubs and washing machine outlets shallbe connected to the water supply system.

3.3.8 Toilet, bath and shower spaces


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3.3.8.1 Space required.Fixtures shall be spaced as per Figure A3-5 Toilet, bath and shower spaces required.

3.3.8.2 Bathtub and shower spaces.

Bathtub and shower floors and walls shall be finished with a smooth, hard and non-absorbent surface.Such wall surfaces shall extend to a height of not less than 1.80m above the floor.


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Fig A3-5 Toilet, bath and shower space required


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Fig A3-11 Septic tank 2500 litres - 5 persons maxi


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Fig A3-12 Septic tank 3200 litres - 8 persons maxi


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FIG A3-13 Soak-away

FIG A3-14 Draining trench3.3.9 Glazing

3.3.9.1 Identification.

Each pane of glazing installed in hazardous locations shall be provided with a manufacturers or installerslabel, designating the type and thickness of glass and the safety glazing standard with which it complies,which is visible in the final installation. The label shall be acid etched, sandblasted, ceramic-fired,embossed mark, or shall be of a type, which once applied cannot be removed without being destroyed.


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3.3.9.1.1 Identification of multipane assemblies.

Multipane assemblies having individual panes not exceeding 0.10m2

in exposed area shall have at least onepane in the assembly identified. All other panes in the assembly shall be labelled.

3.3.9.2 Louvered windows or jalousies.

Regular, float, wired or patterned glass in jalousies and louvered windows shall be no thinner than nominal4.80mm and no longer than 1.20m. Exposed glass edges shall be smooth.

3.3.9.2.1 Wired glass prohibited.

Wired glass with wire exposed on longitudinal edges shall not be used in jalousies or louvered windows.

3.3.9.3 Human impact loads.

Individual glazed areas including glass mirrors in hazardous locations such as those indicated shall pass thetest requirements of CPSC 16-CFR, Part 1201.3.3.9.4 Hazardous locations.

The following shall be considered specific hazardous locations for the purposes of glazing:

1.Glazing in ingress and means of egress doors except jalousies.

2.Glazing in fixed and sliding panels of sliding (patio) door assemblies and panels in doors including walk-inclosets.

3.Glazing in storm doors.

4.Glazing in all unframed swinging doors.

5.Glazing in doors and enclosures for hot tubs, whirlpools, saunas, steam rooms, bathtubs and showers.Glazing in any part of a building wall enclosing these compartments where the bottom exposed edge of theglazing is less than 1.50m measured vertically above any standing or walking surface.

6.Glazing, in an individual fixed or operable panel adjacent to a door where the nearest vertical edge iswithin a 600mm arc of the door in a closed position and whose bottom edge is less than 1.50m above thefloor or walking surface.

7.Glazing in an individual fixed or operable panel, other than those locations described in Items 5 and 6above, that meets all of the following conditions:

7.1 Exposed area of an individual pane greater than 0.80m2.

7.2 Bottom edge less than 450mm above the floor.

7.3 Top edge greater than 900mm above the floor.

7.4 One or more walking surfaces within 900mm horizontally of the glazing.


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8. All glazing in railings regardless of an area or height above a walking surface. Included are structuralbaluster panels and non-structural in-fill panels.

9. Glazing in walls and fences enclosing indoor and outdoor swimming pools where the bottom edge of thepoolside is (1) less than 1.50m above a walking surface and (2) within 1.50m horizontally of the watersedge. This shall apply to single glazing and all panes in multiple glazing.

3.3.9.5 Wind and dead loads on glass.

3.3.9.5.1 Vertical glass.

All glass sloped 15 degrees or less from vertical in windows, window walls, doors and other exteriorapplications shall be designed to resist the wind loads specified in Clause 2.3 Design criteria Table 1 Designpressure for winds. Glazing designed in accordance with these provisions shall be firmly supported on allfour edges.

3.3.9.5.2 Sloped glazing.

All glass sloped more than 15 degrees from vertical in skylights, sunspaces, sloped roofs and other exteriorapplications shall be designed to resist the most critical combinations of loads.

3.3.9.5.3 Thicker glass.

Allowable loads for glass thicker than 6.4 mm shall be determined in accordance withASTM E 1300.

3.3.9.6 Skylights and sloped glazing.

3.3.9.6.1 Definition.

Any installation of glass or other transparent or translucent glazing material installed at a slope of 15degrees or more from vertical. Glazing materials in skylights, solariums, sunspaces, roofs and sloped walls

are included in this definition.

3.3.9.6.2 Permitted materials.

The following types of glazing may be used:

1. Laminated glass with a minimum 0.40mm poly-vinyl-butyral interlayer for glass panes 1.50m2 or less inarea located such that the highest point of the glass is not more than 3.60m above a walking surface orother accessible area; for higher or larger sizes, the minimum interlayer thickness shall be 0.80mm.

2. Fully tempered glass.

3. Heat-strengthened glass.

4. Wired glass.

5. Approved rigid plastics.

3.3.9.6.3 Screens general.


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For fully tempered or heat-strengthened glass, a retaining screen shall be installed below the glass, exceptfor fully tempered glass.

3.3.9.6.4 Screens with multiple glazing.

When the inboard pane is fully tempered, heat-strengthened, or wired glass, a retaining screen shall be

installed below the glass.

Screens not required.

Screens shall not be required when fully tempered glass is used as single glazing or the bottom pane inmultiple glazing and either of the following conditions is met:

1. Glass area 1.50m2

or less. Highest point of glass not more than 3.60m above a walking surface or otheraccessible area, nominal glass thickness not more than 4.80mm, and (for multiple glazing only) the otherpane or panes fully tempered, laminated or wired glass.

2. Glass area greater than 1.50m2. Glass sloped 30 degrees or less from vertical and highest point of glass

not more than 3.00m above a walking surface or other accessible area.3.3.9.6.6 Screen characteristics.The screen and its fastenings shall1 - be capable of supporting twice the weight of the glazing.2 - be firmly and substantially fastened to the framing members, and

3 - have a mesh opening of no more than 25 mm by 25 mm.Curbs for skylights.All unit skylights installed in a roof with a pitch flatter than 25 percent slope shall be mounted on a curbextending at least 100mm above the plane of the roof unless otherwise specified in the manufacturersinstallation instructions.


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3 General Construction3.4 Basic materials

3.4.1 Reinforced Concrete3.4.1.1 MaterialsConcrete shall be manufactured from ordinary Portland cement, sand, gravel and water.3.4.1.1.1

The cement shall be fresh and contained in unopened bags, which have been well protected from

moisture and stored above the ground.3.4.1.1.2

The sand shall be clean (i.e. free of clayey lumps, organic materials and broken shells), natural sharp

sand, preferably taken from an inland source. Beach sand shall not be used.3.4.1.1.3

The coarse aggregate shall be of crushed stone or gravel with a size between 15 and 25mm. The

aggregate shall be free of dust coating. In areas where only broken stone is available, care shall be taken

to use stone as near to 20 mm as practicable.3.4.1.1.4

Only clean fresh water shall be used for the mixing of concrete.

3.4.1.2 Mixing3.4.1.2.1

A concrete mix producing concrete with a minimum compressive cube strength of 21 N/mm2

at 28 days or

16.8N/mm2

at 7 days shall be used. The approximate proportions normally required to produce such a

mix are 42 kg (1 bag) of cement, 0.056 m3

(1 wheelbarrow) of sand, and 0.084 m3

(1 wheelbarrow) of

aggregates and approximately 18 l of water.

NOTE: any moisture affects the maximum amount of water required, which may be present in theaggregate. The quality is therefore reduced when the aggregate is wet.3.4.1.2.2

The cement shall be added by the bag. The fine and coarse aggregates shall be measured in cubic metre

(m3) and the water shall be measured in litre (l).


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3.4.1.2.3

For coastal environment conditions the mix shall be upgraded to 42 kg (1 bag) of cement, 0.056 m3

(1

wheelbarrow) of sand, 0.056 m3

(1 wheelbarrow) of aggregate and approximately 15 l of water.

3.4.1.2.4

The concrete shall be mixed by hand or preferably by machine until there are no visible areas of unmixed

materials and a uniform colour is obtained.

Table B-1 Concrete composition


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3.4.1.3 Form work3.4.1.3.1

The form work into which the concrete is to be placed shall be strongly constructed of straight timber so

braced that no movement or deformation is caused by the wet concrete under normal construction loads.3.4.1.3.2

The form work shall have close fitting joints so that no fine aggregate, cement or water is lost through

leakage.

3.4.1.4 Reinforcement3.4.1.4.1

The minimum requirement for reinforcement steel shall be bars of grade 250 i.e. plain mild steel bars of

250 N/mm2

(minimum yield) stress. This section is based on grade 250 bars; however, higher grades ofplain or deformed bars may be used.3.4.1.4.2 Bar bendingThe minimum pin diameter size for steel bar bending in accordance with TTS583: 2000 must be as

shown in table B-8Table B-8 Recommended minimum size bending

Bar size " d " In mm Steel grade250 420

5 to 16mm 2.5d (12.5 to 40mm) 4d (20 to 64mm)20 & 25mm Not applicable 5d (100 or 125mm)32 & 40mm Not applicable 7d (225 or 300mm)

3.4.1.4.3

Reinforcement steel, which shall be free of loose meal scale (rust), shall be properly tied together by mildsteel tying wire. The whole assembly shall be positioned within the form work with appropriately sized

concrete spacers so that the correct concrete cover to the steel is maintained.


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3.4.1.4.4

Concrete shall not be vibrated by direct contact between the vibrating instrument and reinforcing bar. The

practice of vibrating the form work shall also not be permitted as this may displace the steel fixings. The

practice of vibrating the concrete shall therefore be used with caution.3.4.1.4.5

The recommended concrete covers for normal conditions and coastal environmental conditions are given

in table B-2.Table B-2 Recommended concrete cover

Type Concrete Cover in mmNormal conditions Coastal

environmental

conditionsSlabs 25 35

Beams 30 40Columns 30 40

Surfaces In Contact With

Earth 75 95NOTE The recommended concrete cover for coastal environmental

conditions is based on an increase of 25 % for that of normal conditions.

3.4.1.5 Placing Concrete3.4.1.5.1

Form work shall be thoroughly cleaned to remove sawdust, bits of wood, wire and other debris before

placing concrete in it.3.4.1.5.2

Transporting the concrete over long distances (unless special equipment is used) shall be avoided toprevent segregation of its components.3.4.1.5.3

All runways and routes between the mixer and the area where the concrete is to be used should be set

up beforehand and kept clear, so that the placing of concrete can proceed smoothly without interruptions.


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3.4.1.5.4

The poured concrete shall be compacted in the form work by vibration or rodding, so that dense concrete

is obtained. Where necessary, chutes shall be used to place concrete in tight areas such as column

forms.3.4.1.5.5

Where floor slabs or roof slabs cannot be poured in one operation, construction joints shall be used.

Professional assistance shall be sought on the proper placing of the construction joints in suspended

slabs.3.4.1.6 Curing3.4.1.6.1

The optimum concrete strength shall be obtained by proper curing. To achieve this, the poured concrete

shall be kept moist by wetting with water for two days after it is poured.3.4.1.6.2

Proprietary curing compounds may be used in accordance with the manufacturers instructions.3.4.1.7 Stripping of form workThe side form work of beams and columns may be removed from the fresh concrete after 24 hours. The

bottom form work and props for suspended beams and slabs shall remain in place for not less than 10

days.3.4.2 Timber3.4.2.1 Type of woodWalls, floors and roofs can be constructed of approved structural timber.See Table C1.Preservativelytreated lumberOnly treated timber should be used and shall also be identified.

3.4.2.2MoistureThe timber should be sound, straight and well seasoned timber with moisture content between 15% and

20%.3.4.3 Metal


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3.4.3.1 Structural steelMaterial conforming to one following standard specifications (latest date of issue) is approved for use

under this code.- Structural steel, ASTM A36 is the all purpose carbon steel used in building construction- Welded and seamless steel pipe, ASTM A53, grade B3.4.3.2 Structural shapesAll shapes are published in the ASTM A6 and the principals used are:- W shapes have essentially parallel flange surfaces. The profile of a W shape of a given nominal depth

and weight.- HP bearing pile shape have essentially parallel flange surfaces and equal web and flange thickness.- S beam and C channel have a slope on their flange surfaces.- L angles shape with equal and unequal leg.- Pipe and structural tubing.3.4.3.3BoltsSteel bolts shall conform to one of the following standard specification- Low carbon steel externally and internally threaded standard fasteners, ASTM A307- High strength bolts for structural steel joints, ASTM A325- Quenched and tempered steel bolts and nuts, ASTM A449


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Fig B-1 Foundation types


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4 Foundations

4.1 General4.1.1 Load bearing walls and columns4.1.1.1

All loads bearing walls and columns shall be supported on any of the following reinforced concrete

footings:

a) Pad footingb) Strip footingc) On pileThe above reinforced concrete footings are shown in figure B-1 Foundations types.4.1.1.2

Interior walls shall be supported by thickening the slab under the wall and suitably reinforcing it. The

foundation should be located on a layer of soil or rock with good bearing characteristics. Such soils

include dense sands, marl, other granular materials and stiff clays.4.1.1.3

The foundation shall be cast not less than 600 mm below ground, its thickness not less than 225 mm and

its width not less than 450 mm or a minimum of three times the width of the wall immediately supportedby it (see figures B-2-1a and B-2-1b Arrangement of strip footing)4.1.1.4

When separate reinforced concrete columns or concrete block columns are used they shall be supported

preferably by square footings not less than 1000 mm per side and 225 mm thick (see figure B-3 Typical

spread footing detail).4.1.1.5

When the ground is subject to drying (cracks or fissures) the minimum depth above should be increased

under the advice of a professional engineer.To avoid this increase in depth, the foundation should be protected by surface paving.4.1.2 Reinforcement


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4.1.2.1

For strip footings, the minimum reinforcement shall consist of three 10 mm diameter bars placed

longitudinally and 10 mm diameter bars placed transversely no more than 600 mm between their centres

(see figures B-2-1 and B-2-2).4.1.2.2

For column footings, the minimum reinforcement shall be 12 mm diameter bars at 150 mm between

centres in both directions forming a mesh (see figure B-3).4.1.2.3

Bars may be suitably cranked bent or lapped at the ends. Lapped or cranked lengths shall be a minimum

of 40 times the diameter of the bars being joined. Table A-3 gives the minimum lap lengths for steel

reinforcement.Bar diameter / mm Minimum lap length / mm

6 30010 40012 60016 750

Mesh 150 or one square, whichever is greater


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Fig B2-1a & 1b Arrangement for strip footing 150mm and 200mm vertical core blocksFig B3 Typical spread footing details


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Fig B4 1 and 2 level house type


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Fig B5 Load & non load bearing clay or concrete blocks


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Fig 17-1 2 level house - Typical cross section masonry blocks


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5 Vertical Structures

5.1 Concrete and masonry5.1.1 Masonry Block Walls5.1.1.1GeneralThis section outlines the requirements for structural masonry construction using shear panels for single

and two storey structures as configured in figure B-4 1or 2 level house type.5.1.1.2WorkmanshipCavities shall be clean and substantially free from mortar droppings. Reinforcement shall be placed

centrally and/or properly spaced from the masonry. Reinforcement shall be adequately lapped and

secured. The procedure for applying concrete as outlined in clause 3.7.5 shall be adhered to.

5.1.1.3 Hollow Masonry Blocks5.1.1.3.1

Hollow clay block units shall conform to the latest edition of the ASTM C652-95a Hollow Brick (Hollow

Masonry Units Made from Clay or Shale) and/orASTM C34-96 Structural Clay Load-Bearing Wall Tile.Grade 3 clay blocks cannot be considered as structural.5.1.1.3.2

Load bearing concrete masonry block units shall conform to the latest edition of TTS 16 35 508Specification for Load Bearing Concrete Blocks.5.1.1.3.3

Non-load bearing interior walls or partitions may be constructed using blocks with a thickness of 100 mm

or less. Concrete masonry block units for such application shall conform to the latest edition of TTS 16 35

509 Specification forNon-load Bearing Concrete Blocks.5.1.1.3.4

Figure B-5 shows the various types of load bearing and non-load bearing masonry blocks.5.1.1.4ShearPanels5.1.1.4.1

A shear panel (see figures B-6-1 and B-6-2 Shear panel) is a portion or section of a 150mm exterior wall

that performs the function of resisting lateral earthquake or wind forces.


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5.1.1.4.2

Where masonry is used there shall be a shear wall on each exterior wall of every house.5.1.1.4.3

A shear panel should be 1.8 m in horizontal dimension along the face of the wall and a minimum of 150

mm in block and wall thickness extending from floor to ring beam, with no openings or penetrations. If the

shear panel must be divided in two part the total of horizontal dimension increase to 2.4m with a minimum

of 1000mm for the smallest part. (See figures B-6-1 & B-6-2)Figures B-7-1& B-7-2 shows the various configurations and applications of a shear panel, vertical

stiffeners and openings.Fig B7-1 Typical external wall arrangement - vertical core blocks


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Fig B7-2 Typical external wall arrangement - horizontal core blocks


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5.1.1.5 Block Laying5.1.1.5.1

Blocks shall be laid in half bond courses which have been aligned using lines and levels (see figures B-7-

1 & B-7-2).5.1.1.5.2

Walls at junctions and corners shall be bonded to each other by reinforcement and also interlocked in half

bond. All walls shall be tied to columns or to reinforced corners at every second course.5.1.1.5.3

Horizontal and vertical mortar joints shall be a minimum thickness of 12 mm and shall be properly filled

with mortar.5.1.1.6Mortar5.1.1.6.1

Mortar shall be made using, by volume, 1 part of ordinary Portland cement and a maximum of 4 parts of

clean sifted sand.5.1.1.6.2

Mortar shall be mixed by hand or preferably by a machine until the ingredients are thoroughly mixed (not

less than 3 minutes by machine). A minimum amount of water shall be added to the dry mixture to allow

for workability. There shall be no re-mixing of mortar.5.1.1.6.3

Mortar shall be mixed in appropriate amounts so it is completely used within 1 hour.5.1.1.7Reinforcemen5.1.1.7.1 Shear panelSee figures B-6-1 and B-6-2 with vertical and horizontal core blocks.5.1.1.7.1.1 Vertical reinforcement5.1.1.7.1.1.1 With vertical core blocksShear panels shall be vertically reinforced using 12 mm diameter bars placed a distance of 400 mm

between centres in solidgrouted cells. A 1.8 m shear panel would then have five 12 mm diameter bars

vertically placed. See figure B-6-1.


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5.1.1.7.1.1.2With horizontal core blocksShear panels shall be vertically reinforced using a frame of 2 vertical columns 250mm x 150 mm

minimum with 4 x 12 mm diameter bars placed vertically and 6mm diameter bar stirrup each 150 mm in

solid concrete. See figure B-6-2.5.1.1.7.1.2

Vertical reinforcement bars shall be adequately lapped and secured to hook dowels anchored both in the

foundation and the ring beam.5.1.1.7.1.3

Horizontal reinforcement shall be provided using masonry mesh 50 mm 50 mm 3 mm (2 in 2 in 10

G) or an equivalent every two rows. (See figures B-11-1 & B-11-2)


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Fig B8 Openings and lintels


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Fig B9-1 & 10-1 Typical wall corner & intersection - vertical core blocks


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Fig B9-2 & 10-2 Typical wall corner & intersection - horizontal core blocks


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Fig B11-1 Typical wall reinforcement and phasing construction

Horizontal core blocks


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Fig B11-2 Typical wall reinforcement and phasing constructionVertical core blocks


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5.1.1.8Openings5.1.1.8.1

All openings of 600 mm or greater in any direction shall be reinforced both horizontally and vertically with

a minimum of two 10 mm diameter bars. All bars shall extend a distance not less than 600 mm beyond

each corner of the opening or otherwise anchored by a 300 mm bend inside the concrete frame (see

figure B-8 Openings and lintels).5.1.1.8.2

Lintels with a span of 600 mm or less shall be horizontally reinforced with two 10 mm diameter bars.


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5.1.1.8.3

Lintels with a span ranging from 1.2 m to 1.8 m shall be horizontally and vertically reinforced with two 12

mm bars.

5.1.1.8

.4

For large openings refer to clause Lintels5.1.1.9 Load bearing walls (external and internal)5.1.1.9.1

Masonry walls other than those described above shall be reinforced as follows: -Three 10 mm diameter bars placed vertically at corners (see figures B-9-1 & B-1-2).Four 10 mm diameter bars placed vertically at intersections (see figures B-10-1 & B-10-2).Two 10 mm diameter bars placed vertically at jambs of doors and windows. (See figure B-8)For vertical wall reinforcement (stiffener) 12 mm diameter bars shall be used spaced 1.8m apart (see

figures B-11-1 & B-11-2).Horizontal reinforcement every two rows (see figures B-11-1 & B-11-2).5.1.1.10 Non-load bearing walls (internal walls)The recommended minimum reinforcement for non load bearing walls with concrete block construction(refer to figures B-12-1 & B-12-2) shall be as follows: -a) One 10 mm diameter bar shall be placed vertically at corners.

b) One 10 mm diameter bar shall be placed vertically at junctions.

c) For vertical wall reinforcement 10 mm bars shall be spaced at a maximum of 2.5 m apart.

5.1.1.11 Concrete in fill5.1.1.11.1Vertical core blocks5.1.1.11.1.1

Load bearing walls shall be filled with 1:2:4 nominal mix (refer to table B 1) into the block cores. The

concrete shall be properly compacted, with concrete being added after every two courses of block

erection (see figure B-11-1).


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5.1.1.11.1.2

Non-load bearing walls shall be filled with grout or fine aggregate concrete as the work proceeds (see

figure B-11-1).5.1.1.11.1.3

Pouring of concrete into vertical block cores shall be stopped 40 mm below the top of the block in order to

form a key at joints (See figure B-11-1).5.1.1.11.1.4

The wall reinforcement shall be securely anchored in the wall footing and the ring beam. Horizontal

reinforcement shall be embedded in mortar and shall be continuous through intersections and corners

(see figure B-11-1).


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Fig B12-1 Internal wall arrangement and reinforcement - Vertical core


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Fig B12-2 Internal wall arrangement and reinforcement - Horizontal core


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Fig B13 Ring beam reinforcement


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5.1.1.14 Lintels5.1.1.14.1

Reinforced concrete lintels shall span all door and window openings and shall extend beyond the jambsby not less than 150 mm.5.1.1.14.2

The lintel shall be 200 mm deep for openings not greater than 2.5 m in width.5.1.1.14.3

The reinforcement of the lintel shall be four 12 mm diameter bars and 6 mm diameter stirrups placed 200

mm between centres. Reinforcement bars shall be placed in lintels as shown in figure B-8.5.1.1.15ChasingThe chasing of walls for the installation of services shall be carefully controlled. Horizontal chases at any

one level shall be restricted to 0.7 min length and only one side of the wall shall be chased. Chasing shall

be done before the walls are plastered and then filled with concrete. No chasing of structural members

shall be permitted.5.1.1.16Services5.1.1.16.1

Services shall not be carried through shear panels.5.1.1.16.2

Where services through a structural member other than a shear panel is unavoidable, a sleeve,

preferably metallic, shall be provided during the casting operation. The maximum external diameter of the

sleeve shall be 25 mm. The minimum spacing between sleeves shall be 150 mm.


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Fig 17-2 2 level house Typical cross section columns, beams and shear panel


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5.1.2 Columns, beams and shear panel structure5.1.2.1GeneralThis section outlines the requirements for structural columns and beams construction using shear panels

for single and two storey structures as configured in figure A2-1a and A2-1b for 1or 2 level house type.5.1.2.2Shear panelsDitto "Shear panels" in previous paragraph "Masonry block walls" and "Reinforcement".5.1.2.3 ColumnsColumns construction shall be as follows: -5.1.2.3.1 SizesMinimum dimensions shall be 250 mm 250 mm.5.1.2.3.2Form workColumns shall be formed by form-work on four sides or form-work on two sides with block work on the

other two.5.1.2.3.3Reinforcementa) Square columns,

The minimum column reinforcement shall be four 12mm diameter bars with 6mm diameter stirrups placed150 mm between centres.

b) Round columns,

Where round columns are used, or round columns with varying cross-section (fancy columns) shall havea minimum section of 250mm diameter and shall be reinforced with six (6) 12mm diameter bars with 6mmdiameter round stirrups placed 100mm between centres.

5.1.2.3.4 ConcreteColumns shall be filled with 1:1:1 nominal mix (refer to table B 1).The concrete shall be properly compacted and poured at one time.5.1.2.4BeamsWhere beams are used, construction shall be as follows:


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5.1.2.4.1 DimensionsMaximum span 5000mmMinimum section

See table B-7 (1 to 4)Total height not less than 1/12 span with 300mm minimum. (See table B7)


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Table B7-1 Typical reinforcement for concrete beams - 2 ways slab and MS steel grade 250


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Table B7-3 Typical reinforcement for concrete beams - 2 ways slab and HR steel grade 420

5.1.2.4.2 Form-workBeams shall be formed by form-work on three sides.


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The bottom form-work must be rigid enough to support the weight of the structure, the two other sides

and the rigours. This bottom form support shall remain in place 4weeks minimum.5.1.2.4.3 ReinforcementFor horizontal and vertical reinforcement see table B-7 (1 to 4) and Figures B-17 to 21.5.1.2.4.4 ConcreteBeams shall be filled with 1:1:1 nominal mix (refer to table B 1). The concrete shall be properly

compacted and poured at one time.5.1.3 Framed structure - See next edition to be published


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Fig C1 Wall height


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5.2 Timber5.2.1 Identification & Grade.See characteristics in paragraph "Basic Materials/Timber".5.2.2 Exterior walls.Exterior walls of wood-frame construction shall be designed and constructed in accordance with the

provisions of this chapter.5.2.2.1Stud spacing.In bearing walls, studs, which are not more than 3m in height shall be, spaced not more than is specified

in the following Table C-10Table C-10 Maximum stud spacing

Stud size Supporting roof andceiling only Supporting on floor, roofand ceiling Supporting one floor only

50 x 100mm 600mm 400mm 600mm50 x 150mm 600mm 600mm 600mm75 x 100mm 600mm 600mm 600mm

5.2.2.2 Top plate.

Wood stud walls shall be capped with a double top plate installed to provide overlapping at comers and

intersections with bearing partitions. See figure C-3.Any joints in top plates shall be offset at least 600 mm5.2.2.3Bearing studs.Where floor or roof framing members is spaced more than 400mm on centre and the bearing studs below

are spaced 600mm on centre, such members shall bear within 120mm of the studs beneath.


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Fig C2 Top plate framing to accommodate piping


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Fig C3 Typical wall, floor and roof framing

5.2.2.4 Stud lengthTable C-11 Maximum allowable length of wood studs

Height (m) On centre spacing600m 400mm 300mm 200mm

Supporting a roof only>3m 50 x 100mm 50 x 100mm 50 x 100mm 50 x 100mm3.6m 50 x 150mm 50 x 100mm 50 x 100mm 50 x 100mm


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4.2m 50 x 150mm 50 x 150mm 50 x 150mm 50 x 100mmSupporting one floor and a roof

>4.2m 50 x 150mm 50 x 150mm 50 x 150mm 50 x 150mmSupporting two floors and a roof

>4.2m 50 x 150mm 50 x 150mm 50 x 150mm 50 x 150mm

5.2.2.5Bottom (sole) plate.Studs shall have full bearing on a nominal 40mm or larger plate or sill having a width at least equal to the

width of the studs.5.2.3 Interior load bearing walls.Interior load-bearing walls shall be constructed, framed and fire-stopped as specified for exterior walls.5.2.4 Interior non-bearing walls.Interior non-bearing walls shall be permitted to be constructed with- 50mm by 75mm studs spaced 600 mm on centre or, when not part of a braced wall line,- 50mm by 100mm flat studs spaced at 400mm on centre.Interior non-bearing walls shall be capped with at least a single top plate.5.2.5 Drilling and notching-studs.Any stud in an exterior wall or bearing partition may be cut or notched to a depth not exceeding 25

percent of its width.Studs in non bearing partitions may be notched to a depth not to exceed 40 percent of a single stud

width.

Any stud may be bored or drilled, provided that the diameter of the resulting hole is no greater than 40

percent of the stud width, the edge of the hole is no closer than 20mm to the edge of the stud, and the

hole is not located in the same section as a cut or notch.5.2.5.1 Drilling and notching of top plate.When piping or ductwork is placed in or partly in an exterior wall or interior load-bearing wall,

necessitating a cutting of the top plate by more than 50 percent of its width, a galvanised metal tie not

less than 1.37 mm thick (16 gage) and 40mm wide shall be fastened to each plate across and to each

side of the opening with not less than six 16d nails.


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5.2.6 Headers.For header spans see Tables on floor section.5.2.6.1Wood structural panel box headers.Wood structural panel box headers shall be constructed in accordance with following Table C-12

Table C-12 Maximum spans for wood structural panel box headerHeader

construction HeaderdepthIn mm

House depth in m7.5m 8m 8.5m 9m 9.5m

Wood

structural

panel oneside

225mm 1.2m 1.2m 0.9m 0.9m -450mm 1.5m 1.5m 1.2m 0.9m 0.9m

Wood

structural

panel both

sides225mm 2.1m 1.5m 1.5m 1.2m 0.9m450mm 2.4m 2.4m 2.1m 2.1m 1.8m

5.2.6.2Non-bearing walls.Load-bearing headers are not required in interior or exterior non-bearing walls. A single flat 50mm by100mm member may be used as a header in interior or exterior non bearing walls for openings up to

2.4m in width if the vertical distance to the parallel nailing surface above is not more than 600mm.

For such non bearing headers, no cripples or blocking are required above the header.5.2.7 Cripple walls.

Foundation cripple walls shall be framed of studs not less in size than the studding above. When

exceeding 1.2m in height, such walls shall be framed of studs having the size required for an additional

story. See figure C4.5.2.7.1Bracing.Cripple walls shall be braced with an amount and type of bracing as required for the wall above plus an

additional 15 percent of braced wall length or a maximum braced wall panel spacing to 5.5m.Cripple walls with a stud height less than 350mm shall be sheathed on at least one side with a wood

structural panel that is fastened to both the top and bottom plates, or the cripple walls shall be

constructed of solid blocking. Cripple walls shall be supported on continuous foundations.


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5.2.8 Wall bracing.

Braced wall panels, exterior walls, and required interior braced wall lines shall be constructed in

accordance with this Section. The braced wall panels in the braced wall lines in each story of the building

shall be constructed of a series of one or more braced wall panels.5.2.8.1Braced wall lines.Braced wall lines shall consist of braced wall panels, which meet the requirements for location, method

and amount of bracing specified in following table.Braced wall panels which are counted as part of a braced wall line shall be in line, except that offsets out-

of-plane of up to 1200mm shall be permitted between adjacent wall panels, provided that the total out-to-

out offset dimension in any braced wall line is not more than 2400mm Braced wall panels shall begin no

more than 2400mm from each end of a braced wall line.


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Fig C4 Framing details


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Table C-13 ADJUSTMENT OF BRACING AMOUNTS FOR INTERIOR BRACED WALL LINES

ACCORDING TO BRACED WALL LINE SPACINGBraced Wall Line Spacing Multiply Bracing Amount by:

Meter Coefficient4.5m or less 0.6

6m 0.87.5m 1.09m 1.2

10.5m 1.4

Exterior braced wall lines shall have a braced wall panel located at each end of the braced wall line.1. Linear interpolation is permissible.2. The adjustment is limited to the larger spacing between braced wall lines to either side of an interior

braced wall line.5.2.8.1.1 Sheathing attachment.Fastening of braced wall panel sheathing shall be nailed with 8d minimum.Adhesive attachment of wall sheathing is not permitted.5.2.8.2Braced wall panel construction methods.The construction of braced wall panels shall be in accordance with one of the following methods:1. Nominal 25mm by 100mm continuous diagonal braces let in to the top and bottom plates and the

intervening

small buildings administration of the code

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