While the ‘Beast from the East’ has now ceased, our building surveyors in W1 share some common building defects to be aware of in time for the next big freeze…
Blown Brick Faces
Typically found on areas of brickwork with high exposure and/or older bricks which have not been well maintained or re-pointed when required. This occurs when water saturates an area of brickwork before freezing where it expands by 9% within the brickwork, causing the faces of the bricks to flake off and crumble away. A common cause of this problem is where a wall has been re-pointed using the wrong type of pointing. If a wall was originally pointed with a lime mortar and is re-pointed using a stronger, more rigid and less porous cement based mortar, then water within the brickwork is unable to escape and more likely to freeze internally.
Frozen Water Supply
It is important to ensure that there are no unlagged water pipes externally as the water within would be at risk of freezing which can cause the pipes to burst. It is advisable to lag any exposed pipes so that enough heat is kept within the pipework so that the water remains free flowing. Once a pipe has frozen, which becomes evident when the flow of water from your tap slows or stops, it is important to attempt to thaw the affected area as soon as possible before it bursts and potentially damages your property.
Moisture Ingress through Roofs
If there is a build-up of snow present on a roof, the internal heat of the building can cause the snow present on the roof tiles to melt and run to the outside edges of the roof, the coldest part of the roof. The water can then re-freeze at the edges of the roof and create an ice dam which causes a build-up of snow behind it, once this snow melts it can cause water to pass underneath the roof tiles close to the perimeter of the roof.
Heavy Loading from Snow
More prevalent on flat roofs, an excessive build-up of snow can cause the roof to be over-stressed which in turn can cause it to sag and/or leak. This problem can be exacerbated if it is an older roof with poor drainage. It is important to contact a structural engineer or surveyor to take a look at your roof in the event that you notice additional sagging during or after a heavy snowfall.
Where you have a pitched roof, within the attic space, ensure that there are no gaps within the insulation of the floor space, particularly if there is a build-up of snow present on the roof. If there is a gap where warm air from the level below can pass through then this can cause condensation to occur on the underside of the ceiling within the attic. A dramatic build up in condensation can lead to mould and rot occurring to the timbers of the roof. It is also advisable to ensure there is adequate ventilation to avoid a build-up of condensation.