Building defects database - Chipboard deck failure

Record details

Failure of a chipboard deck. The outline of roof joists is clearly visible. Once moisture has penetrated, the chipboard loses its integrity and effectively collapses. This compounds the problem because water accumulates in the resulting dip, encouraging further penetration and more widespread failure, a vicious circle which will only be ended when the covering and decking are renewed. Decking materials should always be moisture resistant they but may not be present on older roofs.

Effects of condensation on the chipboard deck in cold roof construction. The chipboard has lost its integrity. As it sags rainwater will accumulate above in the resulting dips, potentially increasing the risk of further condensation and raising the likelihood of direct penetration.