CTI - 28/10/98 AR/SR 1/5

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TECHNICALREQUIREMENTS

Part n° 10

Roofing

CTI - 28/10/98 AR/SR 2/5

TECHNICAL SPECIFICATIONS

SECTION N° 10

ROOFING

Page

REQUIREMENTS OF CURRENT REGULATIONS 2

1. GALVANISED STEEL SHEET ROOFING 2

1.1 DESIGNATION OF PANELS1.2 CHARACTERISTICS OF RIBBED PANELS1.3 SUPPORTS1.4 ROOF PITCHES1.5 OVERLAP1.6 PURLIN SPACING1.7 INSTALLATION AND FASTENINGS1.8 ROOF PARTS 1.9 CONDENSATION1.10 ROOF SPACE VENTILATION 1.11 ROOF SPACE LIGHTING

CTI - 28/10/98 AR/SR 3/5

REQUIREMENTS OF CURRENT REGULATIONS

The Contractor will be required to comply with all Mexican Building Codes applying to civilengineering works, insofar as these do not contradict the present list of technicalrequirements.

In general, the Contractor will be required to build the structures covered by the presentcontract in line with normal rules of practice.

1. GALVANISED STEEL SHEET ROOFING: PREPAINTED OR NOT

1.1 DESIGNATION OF PANELS

The panels will be in ribbed, galvanised prefabricated steel sheet. Profiles will beselected by the Employer from suppliers' ranges.

1.2 CHARACTERISTICS OF RIBBED PANELS

For applications in an industrial environment, the ribbed plates will be given a zinccoating of more than 300 g/m² on both sides and possibly extending to 600 g/m² onboth sides.

The corrosion resistance of accessories and fastenings will be the same as that ofthe panels.

The hot galvanised fastenings will receive a zinc coating of 2 g/dm3.

The panels must not come into contact with copper or woods such as oak, chestnutor cedar.

Panel lengths will be chosen by the Contractor who will submit a detailed drawingcorresponding with the overall style of the structure.

The mastic used will preferably be adapted for gun application.

1.3 SUPPORTS

Ribbed panels may be attached to purlins made of metal, wood or concrete. Thecross-sections of the purlins will be worked out according to the distance betweenthe main rafters, taking account of any overloads due to weather (Snow and WindRules).

1.4 OVERLAPS

- Transverse: To be in accordance with roof pitches.

- Longitudinal: this affects the outer rib and should face away from theprevailing rainbearing winds.

1.5 PURLIN SPACING

These vary according to the following parameters:

CTI - 28/10/98 AR/SR 4/5

- overloads due to weather;- inertia of the chosen profile;- thickness of the sheet;- number of bearing points.

1.6 INSTALLATION AND FASTENINGS

The ribbed panels will be laid directly on the framework. The main ribs are arrangedon top and orientated down the line of greatest slope.

1.6.1 ATTACHMENT TO THE FRAMEWORK

Attachments will always be at the top of the main ribs and at the ridgepole sidewith respect to the purlins. The galvanised steel sheet roofing will be attached tothe framework by means of a secondary frame usually consisting of horizontalmetal sections (I, U, L) or wooden sections in certain cases.

The secondary framework will rest upon a metal or wood framework or, in certaincases, a reinforced concrete structure.

1.6.2 DISPOSITION OF FASTENINGS

The hook bolts or draw bolts will be placed with at least 2 per panel and perpurlin on the lateral ribs.

1.7 ROOF PARTS

1.7.1 PROJECTIONS

The projection beyond the eaves may reach 0.40 m.

1.7.2 RIDGE POLES

Prefabricated ridgepoles will be used, possibly hinged.

1.7.3 EDGES

The flashing will consist of galvanised steel plates.

1.7.4 CONNECTION AT WALLS AND SKYLIGHTS

Connections will consist of special parts made of galvanised steel sheet.

1.7.5 PENETRATIONS

Light frames and pipe penetrations will consist of special panels. Ductpenetrations will be made using galvanised steel sheet panels with the same ribsas the normal roofing elements.

1.7.6 STENCH PIPES

Sewer stench pipes will be made up using components similar to the roofingelements and have a downward bend at one end.Ridgepole vents will be of identical design with an upward bend at one end.

CTI - 28/10/98 AR/SR 5/5

1.7.7 GUTTERS

These may be made from galvanised steel sheet or PVC (circular orrectangular).

1.7.8 CHANNELS

Channels will be provided in galvanised steel or PVC. The cross-section ofchannels will be circular or with pronounced corners.

1.7.9 FALLPIPES

Fallpipes will be made of galvanised steel sheet or PVC. Their section may becircular, square or rectangular.

1.8 CONDENSATION

Various approaches may be considered:

The first is to provide effective ventilation for the underside of the roof. For thispurpose two series of openings are made:

1.8.1 either at the gable ends, if these are not more than 12 m apart;

1.8.2 or at the gutter and ridge pole in the case of a lean-to roof;

1.8.3 or at the two gutters, in the case of a double-pitched roof.

If the building is over 12 m long, and if there are openings in the gable ends,intermediate openings will be arranged approximately every 12 m (cross-section ofopenings 1/250 of the roofed area arranged half gutter, half ridge pole).

The second approach is to lay a vapour barrier on the ceiling, always under thethermal insulation. This vapour barrier may consist of a sheet of polyethylene, kraftpaper, epoxy paint, rubber-based paint, etc.

1.9 ROOF SPACE VENTILATION

This must always be provided. The section of the air openings will be at least 1/500of the roofed area (1/250 of the roofed area in a moist atmosphere).

1.10 ROOF SPACE LIGHTING

Lighting will be obtained:

a) By framed roof lights.

b) By translucent panels in artificial resin with the same ribs as those on the roofing elements and laid in the same way.