How to Identify and Remedy Timber Decay

How to Identify and Remedy Timber Decay

Did you know that damp patches appearing on ceilings or walls can be a warning sign of timber decay? If you’ve noticed them in your home, you should investigate further by going up into your loft and taking a look at the timber beams. If they are damp or wet, they may eventually be affected with wet or dry rot or even another fungi type. All of these can cause significant problems if they aren’t adequately treated.

Why does timber decay happen?

How to Identify and Remedy Timber Decay - why does timber decay happen?

Timber decay is a result of several different things. It happens when wood becomes damp and also when exposed to oxygen and specific nutrients. However, the wood needs to be at least 20% wet for an extended period for decay to happen. When all these factors are present, the right environment for fungi exists, causing it to grow. From here, the timber then starts to decay due to a biological attack. 

Recent research shows that timber decay is likely to increase alongside changes in weather. So it’s important to find out more about it and how to spot it.

Do different types of fungi exist?

Yes, there are several different types of fungi, all of which can wreak havoc with timber. Undoubtedly, the most common is Serpula Lacrymans, otherwise known as dry rot. There’s also Coniophora Puteana, otherwise known as ‘cellar fungus’ or wet rot as well as Poria Vaillantii, which is pore or mine fungus. The most damaging type is dry rot because it spreads quickly and can cause severe damage to timbers. Wet rot tends to be less harmful because it only affects the damp portion of the wood.

How do fungal attacks work?

how does timber decay happen?

Where water leaks or dampness exist, this provides the perfect environment for fungi to thrive. Timber is an ideal source of food for many different types of organisms. Fungi germinates on damp wood, forming clumps of growth called mycelium. This is responsible for breaking the wood down for food. As the fungi grow, the wood will turn dark and begin to disintegrate, causing the wood to become unstable. 

Signs your home could be prone to timber decay

As already mentioned, the leading cause of timber decay is damp conditions. Therefore, any area of your home which is leaking or allowing in water could be susceptible. 

Here is what you need to look out for if you’re concerned your home could develop timber decay.

  • Roof (Outside). Blocked or broken gutters. Damaged or missing roof tiles. Damaged flat roof, chimney or flashing.
  • Roof (Inside). Damp or wet timbers.
  • Exterior Walls. Damaged brickwork mortar. Blocked air bricks. Damaged damp proof course. Leaks from water tanks or cisterns. Leaking waste or water pipes. Damaged flashings around window frames.

What to do if you suspect timber decay

You will need to contact a specialist who will investigate the problem further. Some will use insecticidal, fungicidal chemicals. However, they’re not always the best choice. They’re not good for the environment or humans, and they also mean that some timber sections will be lost. Better options include fibre optic or electronic precision-measurement devices. Or, the use of air scenting search dogs which are trained to sniff out timber decay.

Once you’ve had the remedial work completed, you could consider an electronic system that keeps an eye on moisture content in a particular area. It means that if problems re-occur, they can be more quickly dealt with. Plus, overall maintenance costs and home insurance costs may be lowered.


The best things to do if you suspect timer decay is seek professional advice. CJ Bloor are specialists and can help you identify timer decay and diagnose the root cause. Get in contact today for friendly, obligation-free advice.

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