Mold on wood - what you should know

Mold does not only occur on walls - other materials can also be attacked by mold. In addition to leather, paper and textiles, this also includes wood. When a mold on the wood is particularly dangerous, where it occurs frequently, and what you can do about it, learn here.

Wood and molds

Basically, wood moistens more easily than other building materials. Since moisture is the main cause of mold, you can find the mold there quite often. In addition, wood contains very high-quality nutrients for many types of mold. Many molds feed on cellulose, which is abundant in wood.

hazard categories

It is necessary to distinguish in practice where the mold has settled. This creates different risks:

  • Mold on load-bearing timber components (very high risk, because under some circumstances the required load-carrying capacity of the timber component is no longer guaranteed)
  • Mold on non-load-bearing wooden components (lower risk, but destruction of the wooden component possible)
  • Mold on all other wooden components (such as furniture, wood paneling, or the like) - usually only visually problematic

As load-bearing components in buildings are particularly endangered:

  • roof trusses
    Standswerk in Holzständerbauweise
  • Timber framing
  • ceiling beams

It is important to be extremely careful in these areas. In the case of long-term infestation with certain types of mold, it may be necessary to assume that the load bearing capacity of these components no longer exists, because the mold can completely destroy the internal structure of wood.

moisture content

An important criterion for the risk of infestation is the moisture of the wood. In general, wood is only used with low residual moisture (below 20%). This is usually too low for the establishment of mold. Only moistures of more than 25% allow the fungus to settle on the wood.


The best prevention is therefore to always keep the wood dry. As long as there is no moisture penetration or soaking of wood due to building damage or other influences, it is safe from mold. Earth-contacting wood parts (if unavoidable) should always be protected by suitable means against mold and insects. Facade parts that may be subject to driving rain also require additional, effective protection, which should be regularly renewed.

Remove mold from wood

Only with very small infestation points one should try to remove the mold from the wood. For all larger sites, or in case of infestation of several places at the same time, a specialist should be consulted.

Tips & Tricks

A not to be underestimated danger for wood is besides also the dry rot. He is not a mold, but a classic tube mushroom. The dry rot can cause massive damage to wood in no time. It destroys the load bearing capacity of wood components even faster than molds.

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