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Higher Education Academy Engineering Subject Centre

CALVisual

CALVisual for Construction - Defects

All CALVisual images used must be cited.

Defects Part 1

Process Description<br />
Triumphal Arch in Stone<br />
Author: J.Counsell

Process Description<br />
Cracking that is wider (or splits in two) at the top<br />
Author: M.Billington

Process Description<br />
R.C. beams between pads to replace inadequate foundations<br />
Author: M.Billington

Process Description<br />
Cracking that is wider (or splits in two) at the top<br />
Author: M.Billington

Process Description<br />
Cracking combined with outward bowing of brickwork panel about DPC - may extend full height or just for a few courses. The crack is due to expansion of clay bricks particularly where a brick panel is set between concrete columns<br />
Author: M.Billington

Process Description<br />
Vertical cracks at corners can be caused by unrestrained expansion of clay bricks<br />
Author: M.Billington

Process Description<br />
When part of the brickwork is restrained the unrestrained section breaks away<br />
Author: M.Billington

Process Description<br />
When part of the brickwork is restrained the unrestrained section breaks away<br />
Author: M.Billington

Process Description<br />
Vertical cracks at corners can be caused by unrestrained expansion of clay bricks<br />
Author: M.Billington

Process Description<br />
Strong mortar was partly to blame for the extent of cracking. The brickwork would not accommodate movement<br />
Author: M.Billington

Process Description<br />
Typical cracks caused by the rotation of the short return<br />
Author: M.Billington

Process Description<br />
Typical cracks caused by the rotation of the short return<br />
Author: M.Billington

Process Description<br />
Central portion of bay dropping away. In this case the canted flanks were well bonded to the main structure<br />
Author: M.Billington

Process Description<br />
Cracks at the side of a bay are common<br />
Author: M.Billington

Process Description<br />
Provision for movement is especially necessary with concrete and calcium silicate bricks. Diagonal cracking below windows is fairly common<br />
Author: M.Billington

Process Description<br />
Provision for movement is especially necessary with concrete and calcium silicate bricks. Diagonal cracking below windows is fairly common<br />
Author: M.Billington

Process Description<br />
Provision for movement is especially necessary with concrete and calcium silicate bricks. Diagonal cracking below windows is fairly common<br />
Author: M.Billington

Process Description<br />
Provision for movement is especially necessary with concrete and calcium silicate bricks. Diagonal cracking below windows is fairly common<br />
Author: M.Billington

Process Description<br />
Upper section of wall restrained by concrete floor<br />
Author: M.Billington

Process Description<br />
Inadequate allowance for movement<br />
Author: M.Billington

Process Description<br />
Diagonal crack at end of unrestrained parapet<br />
Author: M.Billington

Process Description<br />
Horizontal displacement above a DPC<br />
Author: M.Billington

Process Description<br />
Oversailing of DPC<br />
Author: M.Billington

Process Description<br />
Horizontal displacement in an external wall<br />
Author: M.Billington

Process Description<br />
Movement in a boundary wall<br />
Author: M.Billington

Process Description<br />
The damper section of wall below the window has been more affected by corrosion of the ties causing cracks at every 4th course<br />
Author: M.Billington

Process Description<br />
Cracks in brickwork showing through rendering - in this case probably every 6th course. Movement is cumulative and usually more obvious towards the tops of walls<br />
Author: M.Billington

Process Description<br />
Vertical twist tie showing how corrosion can expand the end embedded in the outer leaf<br />
Author: M.Billington

Process Description<br />
Symptom and repair methods. It is essential to cut back and remove corroded ends of ties from the outer leaf to present continuing movement<br />
Author: M.Billington

Process Description<br />
Expansion and disintegration of mortar due to sulphate attack<br />
Author: M.Billington

Process Description<br />
Expansion of mortar joints shows through rendering. The cumulative effect of movement is more evident towards the top of the wall<br />
Author: M.Billington

Process Description<br />
Expansion of mortar joints shows through rendering. The cumulative effect of movement is more evident towards the top of the wall<br />
Author: M.Billington

Process Description<br />
The first sign will be hairline cracks in mortar joints<br />
Author: M.Billington

Process Description<br />
Brick sub-sills are particularly at risk from sulphate attack<br />
Author: M.Billington

Process Description<br />
Top of wall oversailing due to lateral thrust of roof<br />
Author: M.Billington

Process Description<br />
The think bed joint cracks has been exposed inside the room where plaster has cracked between the solid wall above and the cavity wall below<br />
Author: M.Billington

Download Defects Part 1 (Zip file - size 3,399KB)

Defects Part 2

Process Description<br />
Chimney affected by expansion of mortar joints on one side<br />
Author: M.Billington

Process Description<br />
Chimney affected by expansion of mortar joints on one side<br />
Author: M.Billington

Process Description<br />
Damp patch due to concentration of hygroscopic salts derived from chimney soot<br />
Author: M.Billington

Process Description<br />
Water penetration from a defective flashing<br />
Author: M.Billington

Process Description<br />
Spalling can be provoked by a relatively impervious paint coating that retains moisture in the bricks and makes it vulnerable to frost<br />
Author: M.Billington

Process Description<br />
Salts forming as a layer below the brick surface have forced off the face<br />
Author: M.Billington

Process Description<br />
Gault bricks and fletton bricks are both subject to frost action if used in positions where they remain damp<br />
Author: M.Billington

Process Description<br />
Gault bricks and fletton bricks are both subject to frost action if used in positions where they remain damp<br />
Author: M.Billington

Process Description<br />
Limit blows are caused by fossil nodules in clay bricks that expand as they slake and the defect only affects isolated bricks<br />
Author: M.Billington

Process Description<br />
Calcite stain from concrete can affect brickwork<br />
Author: M.Billington

Process Description<br />
Efflorescence can seriously disfigure buildings<br />
Author: M.Billington

Process Description<br />
Efflorescence can seriously disfigure buildings<br />
Author: M.Billington

Process Description<br />
Efflorescence can pin point defective construction<br />
Author: M.Billington

Process Description<br />
Efflorescence can pin point defective construction<br />
Author: M.Billington

Process Description<br />
Gable wall that has been displaced because the lack of bracing has caused the roof to move sideways<br />
Author: M.Billington

Process Description<br />
Service outlets such as a flue may interrupt bracing and/or binding so the location of flues and water tanks should always be included in the roof truss design and it is essential that service installers are prevented from cutting members<br />
Author: M.Billington

Process Description<br />
Roofs with inadequate diagonal bracing can move sideways until the roof truss meets the wall. Displacements of 100mm or more may occur. In terraces the tiling battens may take the neighbouring roof sideways<br />
Author: M.Billington

Process Description<br />
Movement in roof<br />
Author: M.Billington

Process Description<br />
Roof rafters<br />
Author: M.Billington

Process Description<br />
Roof rafters<br />
Author: M.Billington

Process Description<br />
Deterioration of the tie beam is causing roof to spread at the eaves<br />
Author: M.Billington

Process Description<br />
Change in wall construction and difference in levels of the two leaves of the cavity wall has created a weakness that is easier to disguise than remove<br />
Author: M.Billington

Process Description<br />
The cracks shown in this diagram may be concealed behind fascias and cornices<br />
Author: M.Billington

Process Description<br />
Frost heave under porch produces horizontal cracks in the outer wall<br />
Author: M.Billington

Process Description<br />
Frost heave under porch produces horizontal cracks in the outer wall<br />
Author: M.Billington

Process Description<br />
Sulphate attack on cement in a concrete floor can also cause horizontal cracking<br />
Author: M.Billington

Process Description<br />
Frost (or moisture expansion of clay soil) lifts an abutting construction such as a boundary wall and damages the main structure<br />
Author: M.Billington

Process Description<br />
Expansion of a concrete roof slab can disrupt the surrounding parapet<br />
Author: M.Billington

Process Description<br />
Expansion of a concrete roof slab can disrupt the surrounding parapet<br />
Author: M.Billington

Process Description<br />
Expansion of a concrete roof slab can disrupt the surrounding parapet<br />
Author: M.Billington

Process Description<br />
The balcony parapet has been cracking by corrosion expansion of the rail support<br />
Author: M.Billington

Process Description<br />
Corrosion has split concrete coping<br />
Author: M.Billington

Process Description<br />
A movement joint was pointed up with mortar and the top courses have lifted<br />
Author: M.Billington

Process Description<br />
Corrosion expansion has caused the brick copping to lift<br />
Author: M.Billington

Download Defects Part 2 (Zip file - size 2,901KB)

Defects Part 3

Process Description<br />
Concrete roof tiles on a sagging structure. The ridge on this roof is affected as well as the rafters<br />
Author: M.Billington

Process Description<br />
Typical bowing rafters<br />
Author: M.Billington

Process Description<br />
How a 230 litre water tank should be supported over three trusses<br />
Author: M.Billington

Process Description<br />
Alternative bearer layouts showing how they are supported and related to trusses<br />
Author: M.Billington

Process Description<br />
Alternative bearer layouts showing how they are supported and related to trusses<br />
Author: M.Billington

Process Description<br />
Based on an A frame before being opened up.<br />
Author: M.Billington

Process Description<br />
The rot behind when the facing timber was removed<br />
Author: M.Billington

Process Description<br />
Mould and staining on fibreboard as a result of condensation<br />
Author: M.Billington

Process Description<br />
When sarking felt is not supported at eaves, water will collect and find its way into the eaves construction<br />
Author: M.Billington

Process Description<br />
Decay of nibs of roofing tiles due to magnesium sulphate efflorescence<br />
Author: M.Billington

Process Description<br />
The displacement of the tiles adjacent to the hips is due to the roof construction. The tiles have been laid on feather edge boarding with hips and ridge tiles solidly bedded. When the tiles were laid (during the 1930s) the timber was relatively green and over the years the boarding has dried out and shrunk. The solidly bedded hip and ridge have acted as an arch and have lifted the tiles<br />
Author: M.Billington

Process Description<br />
The rear building shows a typical presentation of slipped and displaced slates<br />
Author: M.Billington

Process Description<br />
Example of slipped stone slates caused by deterioration of the nail heads<br />
Author: M.Billington

Process Description<br />
Typical delaminating slates<br />
Author: M.Billington

Process Description<br />
Typical example of a roof with spalling roof tiles<br />
Author: M.Billington

Process Description<br />
Example of pitted and spalling tiles<br />
Author: M.Billington

Process Description<br />
Example of pitted and spalling tiles<br />
Author: M.Billington

Process Description<br />
Damage to copper due to chimney fumes<br />
Author: M.Billington

Process Description<br />
Detached copper sheet due to inadequate fixings combined with wind action<br />
Author: M.Billington

Process Description<br />
Continual contamination from seagull droppings and inadequate patch repairs has resulted in the deterioration of the copper clad roof<br />
Author: M.Billington

Process Description<br />
Damaged flashing and membrane alongside box gutter<br />
Author: M.Billington

Process Description<br />
Copper membrane removed from bed of gutter to show rotted support underneath. Although example is of a copper lined gutter similar damage can occur under lead lined gutters<br />
Author: M.Billington

Process Description<br />
Nail left in bottom of roll after dressing to the roll, has held the lead too tight and lead has split at nail and cracked at bottom of the roll letting water to the timber structure<br />
Author: M.Billington

Process Description<br />
Lead carbonate on the underside of a lead sheet roof caused by interstitial condensation. The roof deck is also degrading<br />
Author: M.Billington

Process Description<br />
Lead flashing corroded by lichen run off<br />
Author: M.Billington

Process Description<br />
Top of steel roofing showing holes from rusting<br />
Author: M.Billington

Process Description<br />
Underside of steel roofing showing holes from rusting<br />
Author: M.Billington

Process Description<br />
Deterioration coating on profiled steel roof with some rusting occurring<br />
Author: M.Billington

Process Description<br />
Cracks in asphalt typical of movement in the structural deck<br />
Author: M.Billington

Process Description<br />
Crack in asphalt carried over lead drip into gutter<br />
Author: M.Billington

Process Description<br />
Cracks in asphalt typical of movement in the structural deck<br />
Author: M.Billington

Process Description<br />
Typical ponding on a flat roof<br />
Author: M.Billington

Process Description<br />
Ponding has occurred on roof because the falls to the outlets are insufficient<br />
Author: M.Billington

Process Description<br />
In some cases ponding occurs because the outlets have been blocked with debris<br />
Author: M.Billington

Process Description<br />
An example of degraded fibreboard<br />
Author: M.Billington

Download Defects Part 3 (Zip file - size 5,015KB)

Defects Part 4

Process Description<br />
Derelict Rendered Building<br />
Author: J.Counsell

Process Description<br />
Typical spalling eaves on concrete deck<br />
Author: M.Billington

Process Description<br />
Felt splitting at abutment because of localised movement between the deck and the wall<br />
Author: M.Billington

Process Description<br />
Typical example of cracking asphalt upstand<br />
Author: M.Billington

Process Description<br />
Typical example of cracking asphalt upstand<br />
Author: M.Billington

Process Description<br />
The debris accumulated on roof has blocked the outlet causing ponding. The asphalt is also bubbling due to entrapped moisture<br />
Author: M.Billington

Process Description<br />
Inside building showing leakages through the plasterboard ceiling and the saturated permanent plywood shuttering of the roof above<br />
Author: M.Billington

Process Description<br />
Badly slumped asphalt<br />
Author: M.Billington

Process Description<br />
Crazed asphalt<br />
Author: M.Billington

Process Description<br />
Longitudinal crack in asphalt roof<br />
Author: M.Billington

Process Description<br />
General view of roof<br />
Author: M.Billington

Process Description<br />
Close up of area affected by condensed flue gasses<br />
Author: M.Billington

Process Description<br />
Poor drainage on roof terraces increases the likelihood of leakage<br />
Author: M.Billington

Process Description<br />
Aluminium face lifting from felt base<br />
Author: M.Billington

Process Description<br />
Aluminium felt cut to rainwater outlet, rather than being dressed into it<br />
Author: M.Billington

Process Description<br />
Gravel blown into heap leaving areas of roof bare<br />
Author: M.Billington

Process Description<br />
Felt cracked and lap joint opening<br />
Author: M.Billington

Process Description<br />
Badly blistering felt<br />
Author: M.Billington

Process Description<br />
Modern day smokeless fuels are unlikely to produce this degree of smoke. A small quantity of water thrown carefully on the fuel should produce sufficient steam to confirm a problem<br />
Author: M.Billington

Process Description<br />
The source of combustion may be either by a direct or indirect path or a combination of both<br />
Author: M.Billington

Process Description<br />
Chimney outlets must not occur within these dimensions. BSI defines a roof pitch of less than 10 degrees as being considered flat<br />
Author: M.Billington

Process Description<br />
The Coal Board promotes a standard precast concrete throat gather unit<br />
Author: M.Billington

Process Description<br />
Flue terminal much too close to eaves soffit and it should be 600 mm from external corner<br />
Author: M.Billington

Process Description<br />
British Gas stipulated minimum distances for terminal location<br />
Author: M.Billington

Download Defects Part 4 (Zip file - size 20,351KB)