Damp penetration is where the building envelope is not watertight and unwanted water can penetrate into the building. Whilst this can occur in any number of situations, we as inspectors most commonly find damp penetration issues in older style full brick houses such as Victorian terraces and workers cottages, federation and Californian bungalows etc. Victorian and pre Victorian buildings are notorious for damp problems due to the old construction methods employed. External walls are constructed from solid masonry with no cavity between the internal and external walls to prevent lateral water penetration from outside. Also the damp proof course (a waterproofing material in the lower walls – see separate Post) is usually a slate material which is ineffective at preventing the bricks from absorbing moisture from the ground. This combination of rising and penetrating damp is a common problem in Terrace dwellings.
Damp penetration – paint blistering from rising damp
Rectification of damp penetration issues can be complex and expensive, often with varied levels of success.
Environmental factors such as faulty roof plumbing, poor site drainage, restricted subfloor ventilation, and deterioration of the external render and paint coatings can all contribute to damp penetration issues. So any upgrading of these issues can help to mitigate damp. More direct remedial repairs include retro-fitting a damp proof course, upgrading the external render and paint coatings etc.
A damp proof course can cost around $300 per lineal metre of wall, excluding any costs associated with patching and making good to internal surfaces.
Lateral damp penetration around a window opening