Dry & Wet Rot Timber Preservation

Besides brick and mortar, timber is one of the most used elements in London homes. According to trada.co.uk timber is one of the strongest and most flexible building materials, with the added benefit of being non-corrosive. Its sustainability and ease of use make it ubiquitous in all constructions.


Wood maintains its bending strength at a moisture content of 12-15%, while its tensile strength is at its peak at 6-12% levels, according to woodproducts.fi. One potential downside, however, is that timber is hygroscopic, meaning it absorbs water through its pores. If exposed to an environment with a relative humidity above 70% for a prolonged period of time, wood will start to decay and develop fungi that can undermine both the structural integrity of a property and your health.

Not all cases of rot are the same. There are two different categories of fungi that affect timber, dry and wet rot, each requiring a different approach. Therefore, proper diagnosis and action from a qualified professional are essential.

Wet Rot

If left unidentified or untreated wetrot strikes all timbers where moisture ingress and damp occur. Wet rot is the common term used to describe the majority of the fungal species which are responsible for timber decay. The main culprit is a species called coniophoraputeana, followed by poriavaillanti in some cases. Every type of fungus has different features, however the effects and the appearance of the problem is pretty much the same. Wet rot will stick around the affected damp areas and will not spread into the adjacent walls.


If left unchecked, wet rot may cause major structural problems to your property by slowly decomposing the supporting timber. If you believe that you might have a wet rot problem, consider the following:

  • Do you notice any fungal development on timber?
  • Is the timber frail and crumbling?
  • Has the paint become flaky and comes out easily?
  • Does the room have a stale smell?

If the answer to most of these problems is positive, contact us immediately for a free inspection.

Dry Rot

Dry rot requires lower moisture levels to develop and can start spreading internally, masking the symptoms of the problem until itís too late. Mycelium (the vegetative part of the fungus) will spread and travel through masonry, brickwork and all mortars, transporting moisture from existing damp area to dry ones. The ever-developing hyphae can weaken the integrity of a construction and cause even more damage by penetrating the layers of the the construction,


Dry rot can help promote potential outbreaks to other wood-rotting fungus. The most prominent dry rot fungus is serpula lacrymans,which thrives in anaerobic conditions. Therefore, it will most likely appear in poorly ventilated places, such as attics and basements.

Here are some topics to consider whether you have a dry rot problem:

  • Do you notice discolouration and decay of timber?
  • Are there gray strands (hyphae) growing alongside timber?
  • Are there any white, wool-like growths developing from timber?


Damp proofing London provide the following remedial treatments:

Damp Proofing London has a specialist team used to spotting and treating the early and advanced stages of dry and wet rot. Our trained surveyors will determine the source of the moisture ingressgive you a detailed report, as well as suggestions to a proper course of action.

We will then find the best way to eliminate all sources of moisture so as to reduce all timber moisture content to a BBA standard of 20%. We can easily identify affected timber, carefully remove it all and replace it with new treated timber. We then follow up with either a spraylance or brush on fungicidal treatment to all remaining timber as a precaution against further problems.

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Contact us today on:        077 0908 4010

020 8378 0089

Unit 142 Culvert Court, Culvert Road, London, SW11 5AU