Chapter 1.2A consistent approach to finishes

Part 1 General information

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CONTENTS

Page

External walls 1

Fairfaced brickwork and blockwork 1

Appearance of external wall finishes 2

External works 2

Doors and windows 3

Glazing 3

Walls and ceilings 3

Floors 4

Finishes and fittings 4Index 5

SCOPE

This Chapter gives guidance on the suitability of the finishes in new homes.

INTRODUCTION

A consistent approach to finishes gives guidance on the suitability of the finishes in new homes and will be used by NHBC Inspectors during the construction of new homes and by NHBC Claims staff conducting Resolutions under Section 2 of the Buildmark insurance cover. Its recommendations will be considered in conjunction with relevant performance standards and guidance of the NHBC Standards.

The guide is intended to apply at the time the home is physically complete and has passed its NHBC pre-handover inspection. However, some elements may be subject to thermal or drying movement and this may occur both before and after completion. Where appropriate, guidance is given as to the likely changes which may occur during this period.

Many sources of information relating to tolerances have been reviewed in the preparation of the guide. The tolerances given here are considered to be appropriate for the house-building industry and take precedence over other recommendations.

This guide is not intended to deal with every situation that may arise and discretion should be exercised in its application in specific circumstances. The nature and extent of work necessary to remedy minor variances from the tolerances given should be appropriate to the circumstances.

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EXTERNAL WALLSThe variable nature of external wall materials and their useMany of the materials used to construct external walls are not uniform, because of their manufacturing process. Nor are they intended to be. In consequence, external walls will have variations and irregularities. Where reclaimed materials are used there may be even greater irregularities and these characteristics are often intended as an aesthetic feature. The relevant recommendations are intended to be applied in the spirit of this overall context.

Commentary• Bricks and other materials vary in size

and appearance for a number of reasons and in consequence the tolerances and finishes stated in this document may not always be appropriate, especially where reclaimed stock is used. Such materials will need to be considered separately.

• The tolerances described generally apply to entire areas of walling, complete panels and the like, and not to the elements of the construction, such as individual bricks.

• The tolerances do not apply to design features and similar constructional details which are not intended to lie within the limits stated in this document (e.g. quoins, soldier courses, plinths).

FAIRFACED BRICKWORK AND BLOCKWORKStraightness on plan± 10mm max deviation in any length of wall up to 5m.

25 x 25mmspacing blocks

Referenceline

Nominal lineof wall

Max 10mmdeviation

Masonry line

5m 15mm

35mm

Example:Using 25mm wide spacing blocks, the masonryline should be between 15mm and 35mm fromthe reference line.

Note:Spacing block dimensions are a guide only.To suit actual site conditions, final dimensionsshould ensure reference line is kept clear of thewall face.

Level of bed joints± 10mm deviation for walls 5m long (a pro rata tolerance is applicable for walls less than 5m long).

± 15mm deviation for walls over 5m long.

There should not be frequent variations in the level of the bed joints

Line of bed joint

5m

Max deviation Horizontalreference line

Thickness of bed jointsThe thickness of an individual bed joint should not vary from the average of any 8 successive joints by more than 5mm.

Commentary• Bricks and other materials vary in size

and therefore some variation in the thickness of bed joints is likely.

Perpend alignment in external wallsVertical alignment of perpend joints should not deviate significantly from the perpendicular.

Commentary• Because bricks do vary in length

as a result of their manufacturing process, not all perpend joints will align. However, there should not be a cumulative displacement of the perpend joints in a wall.

Plumb of wall - overall heightMax deviation of ± 20mm in overall height of wall.

Overallheight

Plumb of wall - storey heightMax deviation of ± 10mm in a storey height, approx 2.5m.

Example:Using 50mm wide spacing block, the plumb bob should be between 40mm and 60mmfrom the wall.

Note:Spacing block dimensions are a guide only.To suit actual site conditions, final dimensionsshould ensure plumb line is kept clear of the wall face

Plumb line

Storey height

50 x 50mm spacing block

Straightness in sectionMax deviation ± 10mm in any 2.5m height of wall.

Example:Using 25mm wide spacing blocks, the masonry line should be between 15mm and 35mm from the reference line

Note:Spacing block dimensions are a guide only.To suit actual site conditions, final dimensions should ensure reference line is kept clear of the wall face

2.5m

15mmNominal lineof wall

Max 10mmdeviation

Masonry line

25 x 25mm spacing block

Referenceline

35mm

Max 10mm deviation

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Straightness of external reveals6mm max deviation.

straight edge(1m long)

Max 6mm deviation

Straightness of reveal

RENDERING (PLAIN FINISH)Vertical and horizontal flatness± 10mm (excluding features).

Reference line

Equal spacingblocks

Max 10mmdeviation

Max 10mmdeviation

5m

Rendering should have a maximum vertical and horizontal deviation from flatness of ± 10mm in 5m.

Commentary• Features such as bell casts, and the

areas of render in close proximity to the feature, are excluded from the tolerance.

• Flatness is measured in a similar way to straightness on plan and plumb of masonry.

APPEARANCE OF EXTERNAL WALL FINISHESFairfaced brickwork and blockworkFairfaced brickwork and blockwork should be reasonably uniform in appearance, texture and finish.

With certain walls, such as half brick walls, a fairfaced finish can only be achieved on one face. The other face should be left neat and tidy.

Mortar should be reasonably uniform in appearance, texture and finish.

Facing brick units should not have significant cracks in them or other damage such as chips and marks greater than 15mm in diameter.

Commentary• Appearance should be considered for

entire wall areas, panels and the like and not for individual units. Consequently, the wall being considered should, where possible, be viewed in daylight from a distance of 10m.

• Some mortar blemishes will occur on individual masonry units.

• Some variation will occur in the colour of individual masonry units and generally over the wall.

• Some variation will occur in the appearance, texture and finish of mortar.

• Efflorescence occurs naturally in some types of masonry. It is not harmful and usually disappears over time.

• Some brick products have natural or design features which may be in excess of 15mm in diameter.

• Some minor shrinkage cracking may occur between masonry units (bricks and blocks) and mortar joints.

RenderingRendering on walls should be reasonably consistent in texture, finish and colour.

Commentary• Rendering should, where possible,

be viewed in natural daylight from a distance of 10m.

• Some minor cracking and crazing is likely to occur but should not be such as to affect its performance.

• Some patches and daywork joints may be visible but should not be unduly obtrusive.

Tile hangingPanels of tile hanging should be reasonably uniform in appearance, particularly at abutments.

Commentary• Tile hanging should, where possible,

be viewed in natural daylight from a distance of 10m.

• Certain handmade tiles vary in size and may not be of a uniform appearance.

• Some variation in colour may occur in tiles.

EXTERNAL WORKSDrives and paths - standing water

Surfaces should minimise the potential for standing water.

Commentary• One hour after rain has stopped, isolated

areas of temporary standing water up to 1m2 and no deeper than 7mm are considered to be reasonable.

Drives and paths - variations in surface finishVariations in the surface should not exceed ±10mm deviation from a 2m straight edge with equal offsets.

Commentary• Some minor variations in surface levels

including scuffing and pitting may arise due to settlement, natural ground movement and vehicle use. In gravel and other loose surfaces, displacement of stone etc., will require some maintenance by the homeowner.

• Localised falls into gulleys and channels are acceptable.

Covers to the drainage system

Covers to the drainage system in hard paved areas should align with the adjacent ground.

Commentary• In hard landscaping, some settlement of

the area immediately around the cover is to be expected. The difference in height between a cover and the adjacent hard surfaces should be not more than 10mm.

• In soft landscaping, such as lawned areas, some settlement of the ground may occur and would be made good by the homeowner as part of normal household maintenance.

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DOORS AND WINDOWSOpenings in walls (including external openings viewed from the inside)

Reveals, head and sill

Head and sill: Max out of level tolerance 6mm for openings up to 1.5m wide. 10mm for openings more than 1.5m wide

Flatness along thelength of sills andwindow boards ± 3mm in 1m

Max 3mm out of level across reveal (measured from frame)*

*Tiled sills, for example, in bathroomsmay be intentionally laid slopingaway from the window

Reveals:Max out of plumb tolerance 6mmfor openings up to 1.5m high. 10mmfor openings more than 1.5m high

Maximum ± 8mm deviation off squareinto reveal up to 200mm deep

8mm 8mm

Gaps and distortion

Window and door frame should not be distortedin the opening

Max 5mm gap between doorand head of jamb (for firedoors the manufacturer’s recommendationsshould be used)For double doors the gap at the meeting stiles should be max5mm

The gap between the underside of an internal door and unfinished floor (concrete, screed, etc) should be min 5mm and max 22mm

Max 10mm out ofplumb over height of frame (in onedirection only)

These dimensions arewithout prejudice tosatisfactory performance in terms of weathertightness,exclusion of draughtsand fire resistance where appropriate

Door distortion:Max 5mm across widthMax 9mm in height

Window frames upto 1.5m in height –max 6mm out of plumb.Over 1.5m in height – max 10mm out of plumb.

GLAZINGWhen viewed in daylight from within the room and at least 2m from the panes (3m for toughened, laminated or coated glass) and looking at right angles through the glass, the following are acceptable if they are neither obtrusive nor bunched:• bubbles or blisters• hairlines or blobs• fine scratches not more than 25mm long• minute particles.

Commentary• The above does not apply within 6mm

of the edge of the pane, where minor scratching is acceptable.

WALLS AND CEILINGS (PLASTERED AND DRY LINED)Wall and ceiling surfaces

For all wall and ceiling surfaces no sharpdeviations exceeding 4mm in any 300mm

Plumb of wall finish:Max 10mm out of plumb in a storey heightup to 2.5m - max 20mm out of plumb for a continuous wall height greater than 2.5m

Flatness of wall, Max deviation ± 5mm from 2m straight edge with equal offsets,horizontaland vertically

5mm

5mm

2m

Level of ceiling Max 10mm deviation in 2m

Max 15mm deviation using 500mm square

15mm 15mm

Flatness of ceiling:Max ± 6mm deviation from 2m straight edge with equal offsets

± 8mm in 200mm

± 8mm in 200mm

2m

Surfaces should be reasonably uniform although there may be minor textural differences around lights and other fittings. There should be no visible gaps between fittings and the wall/ceiling, e.g. around switch plates.

In plastered walls and ceilings some tooling marks may be visible.

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In general wall surfaces, some cracking (up to 2mm wide) is likely, due to shrinkage and differential movement of materials and should be made good by the homeowner as part of normal household maintenance.

JunctionsAt wall, floor and ceiling junctions where there are changes in the construction materials used, small cracks (up to 2mm wide) may appear in the surface as a result of shrinkage and differential movement of materials.

Duct casingsDuct casings, access covers and any associated framing should be neat and tidy and have an appropriate decorative finish.

SkirtingsJoints in skirtings are likely in long lengths of walls. Joints should present a continuous appearance when viewed from a distance of 2m in daylight. Some initial shrinkage of the skirting may already be evident at completion of the property.

Gaps in skirtings may appear at joints and corners due to shrinkage and should be made good by the homeowner as part of normal household maintenance.

Blockwork walls in garagesNormal drying out shrinkage may lead to cracking of unplastered blockwork walls. Thermal movement and drying shrinkage may become evident but cracks of up to 3mm are generally considered to be normal.

Commentary• Small cracks may occur in wall finishes

which pass across floors e.g. in walls adjacent to a staircase.

• Where stair strings abut a wall a crack of up to 4mm may appear as a result of shrinkage of materials and should be made good by the homeowner as part of normal household maintenance.

FLOORSLevel of floorMaximum 4mm out of level per metre for floors up to 6m across, and maximum 25mm overall in any other case.

Flatness of floorMaximum ±5mm deviation from a 2m straight edge with equal offsets.

Skirting to floor gapA gap of up to 5mm can be expected between the floor finish (without coverings) and the bottom of the skirting in a newly completed home.

The gap between the floor finish and the skirting may increase because of drying out shrinkage and deflection, particularly in timber floors. A gap of up to 10mm is normal but exceptionally 15mm may be seen where timber floors have long spans

or there are heavy items of furniture on the floor.

Floor screedsAs screeds dry, they may shrink causing minor cracking, which requires no remedial action.

Underfloor service ductsService ducts should be constructed so that the cover is level on completion with the adjacent floor finish provided by the builder.

Commentary• Drying shrinkage of the floor may result

in minor differences in level between the floor and duct cover. This may become evident with some types of thin floor coverings, and the choice of covering should take this into account.

Timber floors and staircasesTimber floors and staircases are made of materials which naturally shrink as they dry. As this drying occurs, it may result in squeaking of components as they move against each other. This is natural and to be expected. Some squeaking is to be expected and cannot be totally eliminated.

FINISHES AND FITTINGSPainted and varnished surfacesSurfaces should be reasonably smooth and free from nail holes, cracks and splits. Joints should be filled. Colour, texture and finish should be reasonably uniform.

Commentary• Surfaces should be viewed in daylight

from a distance of 2m and not by shining artificial light along the surface. Wall lights or uplighters should be switched off.

• Painted and varnished surfaces should be free from conspicuous runs and prominent brush marks. There should be no bare or starved areas.

• Timber surfaces may show limited raised grain and the colour and texture may also vary.

• Drying shrinkage of timber may cause cracking of the paint finish, particularly where joints occur in plaster and woodwork, and should be made good by the homeowner as part of normal household maintenance.

• Where painted surfaces are touched-up, minor colour variations will occur.

• External finishes will dull over time depending on a number of factors such as exposure to sunlight, rain and pollutants. To minimise the dulling, surfaces should be washed regularly to remove the accumulation of dirt and grime.

Knots in timberSome exudation of resin from knots may occur and may cause discolouration of paintwork, both internally and externally.

CommentaryBecause timber is a natural material some resin is likely to exude from knots even though modern primers contain a knotting compound to limit the effect.

Fitted furniture (kitchen, bathroom and bedroom)Doors and drawers of fitted furniture should be visually aligned vertically, horizontally and in plan, and operate as intended by the manufacturer.

Gaps between adjacent doors and/or drawers should be uniform.

There should not be a significant difference in level at the intersection of adjacent worktops.

Commentary• No dimensional tolerance has been set

for gaps between adjacent doors and/or drawers or for their alignment because some variation will be necessary to take account of adjustments as part of the fitting process. Over time doors and drawers may need some adjustment by the homeowner as part of normal household maintenance.

• No dimensional tolerance has been set for the abutment of adjacent worktops because of the variety of materials available and because minor variations, even with manufactured products, are inevitable and small differences in height may be unavoidable.

• Fitted furniture should normally be viewed from a distance of 2m.

Scratches on doors (including fitted furniture), windows and framesFactory-finished door and window components should not have conspicuous abrasions or scratches when viewed in daylight from a distance of 0.5m.

Commentary• Conspicuous surface abrasions caused

during the building-in process should be removed in accordance with the manufacturer’s recommendations which may include polishing out, re-spraying or painting as appropriate.

• In rooms or areas when there is no daylight, scratches should be viewed in artificial light from fixed wall or ceiling outlets and not from portable equipment.

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INDEX

A

Appearance of external walls 1

B

Bathroom fitted furniture 4Bed joints 1Bedroom fitted furniture 4C

Covers to drainage system 2D

Doors and windows 3Drives and paths 2Duct casings 4E

External reveals, straightness 2External wall finishes 2External walls 1External works 2F

Fairfaced brickwork and blockwork 1, 2Finishes and fittings 4Flatness of floors 4Floor screeds 4Floors 4

G

Garages, blockwork walls 4Glazing 3J

Junctions 4K

Kitchen fitted furniture 4Knots in timber 4L

Level of bed joints 1Level of floors 4O

Openings in walls 3P

Painted and varnished surfaces 4Perpend alignment 1Plumb of wall 1R

Rendering 2

S

Scratches 4Skirting to floor gap 4Skirtings 4Standing water 2Straightness in section 1Straightness on plan 1T

Thickness of bed joints 1Tile hanging 2Timber floors and stairs 4U

Underfloor service ducts 4V

Variations in surface finish 2W

Wall and ceiling interfaces 4Wall and ceiling surfaces 3Walls and ceilings, plastered and dry lined

3

Windows and door openings 3