The Two Types of Rot

There are two different types of rot - wet and dry. Both are direct results of dampness. Timber used in new construction is treated with preservative to prevent the development of rot (and woodworm), but many existing timbers will not have been treated.

1. Wet Rot

Is the more common problem and is identifiable as general decay of the timber, with darkening of the wood and cracking along the grain. It is common in window sills, window frames, and where door frames meet the ground.

If wet rot is extensive, timbers will need to be cut out and replaced (a job for a builder or carpenter), but small areas of damage can be repaired using a wet-rot repair kit. All damaged timber must be cut out, the area coated with a wood hardener, and preservative pellets inserted into the holes in the wood, before filling with a flexible (but hard-setting) exterior-grade wood filler.

Once the filler has set and been sanded down, the repaired area can be repainted.

2. Dry Rot

Is much more serious. It is identifiable by a strong musty smell, thin white strands growing into cottonwool-like sheets on the cracked grey timber surface, and, in bad attacks, the growth of fungal 'fruiting bodies'.

Dry rot can also spread across and through masonry, and is so serious that all affected timber and masonry must be removed (and the timber burnt) and the area sterilized before new materials are added.

Only professional firms have the expertise and equipment to treat dry rot.