BU550 Damage from weathertightness failure (2012)

Weathertightness failure of a wall cladding system can lead to health problems for occupants and significant building damage including fungal decay of timber, toxic mould growth and corrosion. This bulletin outlines the damage that can occur when water enters and remains within a building and the repair options available.

This bulletin replaces Bulletin 434 Results of weathertightness failure.

The bulletin covers:

• causes of weathertightness failure
• typical water entry points
• moisture-induced damage
• causes of structural damage, including fungal decay of timber, rots, corrosion and moulds
• treatment of timber against fungal decay
• construction remedial options
• replacing timber.