Building defects database - Damp penetration through roofing

Record details

Persistent leakage through a valley gutter can cause rot in the timbers beneath. Understandably the area most seriously affected can often be towards the base of the valley, where moisture naturally accumulates and there is reduced internal ventilation. Unfortunately, this is also likely to be the area least visible and accessible from within the roof space. It may take exposure works to reveal the full extent of problems.

The lower part of this clay pantile roof is too shallow where the roof has been extended over the rear parts of the property. The cement infilling was presumably an attempt to prevent the inevitable damp penetration. Replacing the covering with an alternative material such as roofing felt or EPM may be the only solution. A surveyor using binoculars from the ground would not see accumulated debris blocking the chimney back gutter, but should at least inform the client of this likely problem.