Most flat roofs consist of a timber decking nailed to the roof joists covered with three layers of roofing felt. They are often used on house extensions and garages. Using a layer of proprietary chipping compound, such as limestone, gravel or granite on top of the layers of felt, strengthens the surface further. The idea is for the surface to reflect rather than absorb sunlight, thus helping to protect the felt.
Check for water staining on the ceiling as this will indicate dampness getting through. Felt covering can deteriorate with age and become porous. This can result in the surface becoming uneven, buckling or cracking in areas. On a particularly wet day, check for drips of water seeping through the surface. It is useful to inspect the ceiling after a long period of rain, as the source of a leak is easier to trace. If stains are found, try tracing the source of the stain as it is not always directly overhead. Water can penetrate the roof surface and travel between the roof and ceiling level before finding its way through the ceiling.
Outside at ground level
Outside, check the roof by inspecting at ground level. Check the apron, which is the area where the edge of the front of the roof does not meet a wall. Here strips of felt are secured over facia boards, sealing the edges of the roof. If there is a change to the colour of a section, it could be newly exposed and therefore unweathered. If the roof is too high to allow you comfortable access by ladder for a closer inspection, use binoculars to scan the surface as carefully as possible, from all angles - front, back and sides where applicable.
At the roof level
If you are using a ladder, always make sure it is set up correctly and long enough - at least 3 rungs above the gutter. Always work with someone standing near by when you are working at a height. See our Ladder Users Guide for details on how to use a ladder correctly and safely. Once at the roof level, only access the surface of the roof if you are sure that the structure is safe. If there are signs of dips in the roof or puddles, it could be due to the deck or the structural joists having deteriorated or perished. If you have no confidence in the strength of the roof taking your weight, use scaffold boards across the roof in order to spread the load when you walk across it. Ladders and scaffold boards can be hired.
If patch repairs are regularly necessary, it may be time for the roof to be re-covered. It can be difficult for an amateur to decide whether to attempt a repair or replace the roof. If you need advice about the soundness or safety of your roof, contact one or two builders for their opinion.
Alternatively, pay a surveyor or architect for an unbiased report on its condition. A contractor, who will guarantee the work completed, should undertake major roof repairs or replacement of sections.
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