The greatest damp risk to a property is rot

The most virulent and damaging rot to a property is dry rot (serpula lacrymans). Dry rot can spread rapidly, but may only become noticeable when a fruiting body forms under biological threat, such as during a summer’s heat wave, loss of food or competition from another rot or outbreak of dry rot.

Brown rots are the most dangerous to structural timber, as they cause cuboidal cracking (cracking across as well as along the grain), such as cellar rot (coniophora puteana).

White rots, such as window rot (phellinus contiguus) are common, particularly around external timber frames. Generally there are no a structural problem.

Simple rules for rot

  1. Rot needs wet timber to exceed 28{f898b7ccba74aedaf6f9f165b1651d39d829939f1b62e7036dcda8fdc0245a9d} moisture to break open cells.
  2. Rot spores are omni-present (everywhere), so expect rot if you have wet timber.
  3. Lack of ventilation is the main issue with brown rots (e.g. dry rot).
  4. Rots (like humans) need oxygen and produce water as a by-product of respiration.
  5. So once a rot gets started only evaporation through ventilation will stop it.
  6. Stop the source damp and ventilate – the rot will die – even dry rot (but it may take a year).
  7. If there’s insignificant structural decay, then leave the timber to dry throughly (few weeks) then check strength again once dry.
  8. If there is structural damage then replace the timber that it damaged and look to support from sub-floor walls or brackets.
  9. Overall – no source of damp = no rot
  10. Overall – ventilate = no brown rot

If you look at a wooden post, the rot is only found a few centimetres from the ground, the area where there is sufficient water (minimal ventilation), but it gets sufficient oxygen to respire.

Damp Treatment Fails

Yesterday we surveyed two properties both with damage caused by a large chemical damp proofing company. Here’s a snippet of the Plc’s failures. Damp treatment failure Ask for more details of what goes wrong when damp is misdiagnosed and why it causes more problems than it solves. Please add your comments.

Estate agent

24hr turn around Ask us for a Priority Urgent Damp Report (Damp and Timber Reports) Vendors Buyer are unhappy to spend additional money on a damp survey. Builders (damp contractors) offer quotes for works, which they call damp surveys, so what do you expect…. a £10,000 estimate for rising damp and renegotiation. Agents are seeing …

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