Monday, 17 January 2011

Dry and Wet Rot Specification

Wet Rot

There are a number of wet rot fungi which attacks wood when its moisture content reaches 40-50% or higher. The more common wet rots are the Cellar fungus (coniophora puteana) and pore fungus (Fibroporia vaillantii). The most common is the cellar fungus.

Specification for Treatment

Open up the affected areas and remove unsound timber from site in accordance with our Timber Replacement Schedule. All remaining sound wood is treated to refusal with fungicidal preservative. All replacement timbers are treated with preservative and where in contact with damp brickwork, are isolated by a damp proof barrier.

For Wet Rot Treatment contact City Damp Proofing

Dry Rot

There is only one dry rot fungus, Serpula lycrymans. It presetns a far more serious problem than wet rot, since it can grow at very much lower moisture contents (as low as 20%) and can penetrate damp masonry. It normally attacks timbers where there is inadequate ventilation and exposed to damp. Once germinated it can spread rapidly and extensively resulting in the total decay of exposed timbers.

Specification for Treatment

Open up the area to at least 1 metre beyond the last visible signs of infestation and where masonry adjacent to timber is damp. Cut away plaster, remove paneling, skirting and floorboards to expose brickwork and provide access. Remove all timber built in to brickwork such as bond timbers, lintels, plates, pads and grounds. Cut out and remove from site all decayed timber.

Spray all timber within 1 metre beyond the visible sign of growth with an organic preservative complying with British Standards. Larger dimension timbers may be treated by an application of bodied Mayonnaise paste to increase penetration.

Reinstate wall plaster incorporating masonry anti-funicide in sharp sand and cement render mix 2 coats followed by multi-finish or other suitable plaster finish.

Remove fungal strands from the wall surface (and/or oversite where appropriate) by brushing, sterilize with a masonry fungicide. If considered necessary holes will be drilled into the brickwork or masonry and irrigated with masonry anti-fungicide for deeper treatment.

For Dry Rot Treatment click here to contact City Damp Proofing

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