Wet and dry rot usually effect areas that have been subject to prolonged damp (over 20% moisture content). A short period of damp, should not cause a problem. Curiously, dry rot does in fact need damp conditions to start it off. Dry rot is very serious and should be dealt with thoroughly and quickly. In older properties the cause of the rot is usually penetrating damp. In the roof this may be due to old or defective gulleys, or due to defective guttering and downpipes.


Rising Damp

There are several different types of worm that attack wood. Common Furniture Beetle is the most well-known. Many older houses have had woodworm in the past but it may not still be active. If it is there will be fine "sawdust". Put a piece of clean white paper under the timber and see if any of the dust is deposited. If not, it is probably an old infestation and there is nothing to worry about. Other types of "worm" are the worryingly named death watch beetle and the longhorn beetle

Rising Damp usually occurs in older properties (pre 1880) where there is no damp proof course . It usually does not rise more than a metre above ground level. Injection damp proofing is a possible remedy, where a chemical is injected into the wall. The wall then needs to be replastered up to a height of one metre. Many building socieities will insist on a chemical damp proof being injected where there are signs of rising damp. However, there is some dispute as to the effectiveness of such remedies particularly where the wall is of rubble fill construction. More advice is available at http://www.periodproperty.co.uk/discussion_forum.htm. Other types of damp are penetrating damp, often caused by damaged downpipes and guttering, and condensation caused by poor ventilation.