There are three main types of timber decay but lots of causes!
Wet rot is probably the commonest. If you have lived in a 1960’s house or flat for any length of time you will be familiar with wet rot galloping around the window frames, door frames and the fascia boards decaying, despite careful painting and maintenance. The reason was the wrong timber was used due to shortages following the explosion of building in that period.
Buildings of all ages can be affected by wet rot as it is a fungus which feeds on timber, the timber must be damp or wet for the fungus to thrive and continue the rotting process. Take away the cause of dampness and the rot stops. This is not rocket science but wet rot continues to occur in buildings, due mostly to lack of maintenance, including leaking roofs, flashings, gutters, waterpipes, and proper decoration. The use of timber with a higher resistance to rot, better design of joinery and use of preservatives have gone a long way to reduce the problems of wet rot. The installation of PVC-u external joinery has almost totally elimimated the problems which were so prevalent in the past.
One area where wet rot is still alive and doing damage is in sub floor timbers in old buildings where they are subject to continual dampness from contact with damp brickwork and walls. Many floor joists are supported on old timber wall plates built into the external brick walls or on wall plates lying on low brick walls with an inadequate or no damp proof course. Another area where wet rot occurs in old buildings is in timber skirtings on walls which have suffered from rising or penetrating dampness and the correct remedial works have not been carried out, despite installation of damp proof course systems and replastering. Wet rot can affect the bottom of internal door frames and staircase timbers. Cellar and basement stairs are favourite places. Anywhere dampness is present you can expect to find wet rot in adjoining timbers.
You make think for example that buying an old oak timber framed building is a good choice as oak is such a hard and resilient timber. Unfortunately, because of our damp climate and the general lack of expertise in the repair of these buildings, bodge repairs are carried out over long periods of time, trapping further moisture and exacerbating the problem. In some instances parts of, or whole walls are rendered over externally in an attempt to keep out the weather. This more often than not creates further problems of damp ingress, moisture becomes trapped with no escape, so causing further decay. It is not unusual to find a 9” long (225mm) thin bladed screwdriver disappearing up to the hilt in ”Rock Solid Hearts of Oak Timber”! If you are buying or leasing an old building, a thorough inspection of the visible and accessible timbers is always recommended. This is routinely included in Structural Surveys and Building Condition Surveys.
The treatment of timbers affected by wet rot is usually fairly simple. Badly affected timbers need replacing and the source of dampness removing. There are also numerous treatments available. The new timbers should preferably be pre- treated before installation. Existing timbers are normally sprayed with a fungicide solution. In some circumstances, the timbers can be treated with a fungicidal paste, especially when the timbers are built in and removal would cause a lot of disruption and expense. Timber treatment can be carried out by specialist companies and guarantees provided.
This practice routinely carries out inspection for timber decay as part of a Building Survey or as a specific request where decay or problems have been found or are expected.
Dry Rot is a less common fungus but a better known name and was the name of a good Brian Rix farce in the 1960’s. Dry rot is less visible in its early days as it avoids light and thrives in warm, moist /damp dark, airless surroundings, sealed up underfloor cavities, sealed in box gutter timbers, sealed flat roofs, timber bressemers and timbers built into damp solid walls are favourite places. The fungus normally only becomes more evident when the attack is advanced and affects the surface of the timber. The fungus differs from wet rot as it feeds on the cellulose in the timber which does not have to be in contact with a damp surface for it to break out and thrive. Dry rot spores are found all over buildings and lie dormant, waiting for the right conditions to develop or occur. Dry rot is more of a problem when it becomes established as it can travel through and along the underside of plaster over long distances, can travel through brickwork into adjoining buildings and travel vertically through several floor levels. Dry rot will travel along the affected timbers turning the timber into powder. Often when disturbed or conditions alter the fungus will develop a fruiting body which can grow into a football sized mass containing millions of spores which are then dispersed. Each spore is capable of starting a new dry rot outbreak.
Treatment usually requires the removal and burning of all affected timbers and replacement with specially treated timbers and the removal of the conditions causing the outbreak. Where timbers are too difficult to remove without causing serious damage to the remainder of the fabric they can be treated with slow release fungicidal paste and the surrounding masonry surfaces drilled and injected with fungicide. Surface mycelium – the white spidery threads of the fungus can be burnt away. It is possible for the dry rot to lie dormant in pockets in the brickwork and the best way of preventing a further outbreak is to be aware of the causes, be vigilant and practise good maintenance. There are numerous treatments available for spraying out of the timbers with low odour fungicides and guarantees can be provided by specialist companies.
This practice routinely carries out inspection for timber decay as part of a Building Survey or as a specific request where decay or problems have been found or are suspected.
Wood Boring Beetles
There are numerous beetles in this country which feed on timber in and around buildings. Some are restricted in diet to hard woods eg Death Watch beetle, to bark- the Bark Beetle, posts- the Powder Post beetle, some are only found in certain areas, eg the House Long Horn Beetle and some are general purpose beetles eg the common furniture beetle or woodworm to give it its colloquial name. The latter is probably the best known of the beetles as their presence is apparent from flight holes in floor boards staircases in roof timbers particularly where thatch is present and in old furniture which was probably the cause of the outbreak. Woodworm hatches from an egg laid in the timber and lives as a grub feeding in and on the wood for several years before pupating and then eating its way to the surface. It then emerges as a flying beetle, leaving the exit woodworm holes and flying off to mate and start the process again, leaving behind the well known woodworm holes. All beetles cause damage to the timber as they feed on it. The extent of infestation and damage caused can only be determined by carrying out a thorough inspection of the timbers which usually entails opening up of floors and in some cases the removal of plaster and claddings. There are numerous treatments available for spraying out of the timbers with low odour insecticides and guarantees can be provided by specialist companies.
This practice routinely carries out inspection of timbers for signs of beetle infestation as part of Building Surveys or on specific request where beetle infestation or problems have been found or are suspected.