A Guide To Dry Rot

What is dry rot?

Dry rot is a type of fungal decay, which is caused by spores that are present in existing structures within the home, including timber frames. Spores spread in contact with moisture causing wet and dry rot. Dry rot is a term that causes heart rates to rise. Dry rot is never good news. Whether you are selling your home, or you’re hoping to buy and a house survey has identified signs of dry rot, it’s wise to know what to do next.

Dry rot can start to develop when the moisture content of the surface, usually timber, reaches 20%. Wet rot develops once moisture levels reach 50%.

Signs to look out for

Dry rot can be difficult to spot because it tends to develop in areas that are not visible or accessible, such as behind walls, under flooring and in basements and attics. Signs a surveyor may look for when doing a house survey include:

  • Cotton-wool like structures, which are either white or grey: this is known as mycelium
  • Warped timber and shrinkage
  • Damp, musty odours
  • Fruiting bodies, known as sporophores, which resemble large mushrooms
  • Deep cracks in the timber
  • Patches of yellow-orange spore dust

Is it possible to stop dry rot?

Research conducted by the Property Care Association suggests that dry rot is becoming more commonplace in the UK. As timber accounts for up to 70% of the framework and fabric of most houses, and our homes are exposed to moisture and damp through frequent rainfall, it’s no surprise that dry rot is common.

The best way to treat dry rot is to prevent it from accessing moisture and food. The first step is to check for a source of excess moisture, such as a leak or damp caused by damage to the roof or a faulty pipe. Once moisture levels fall, the second step is to remove and replace the damaged wood. New wood should be sanitised and it’s wise to contact professionals to undertake this job. Experts will inspect the timber and discuss how much needs to be removed and give you a quote. Once you have treated dry rot, you can follow advice and instructions to minimise risks in the future and protect your home.

When dealing with dry rot, it is essential to seek expert advice. If you are selling your home, it is a good idea to get the issue checked out before you accept an offer and a buyer arranges a building survey. If you are buying a property and the house survey identifies signs of dry rot, consult your surveyor and get quotes for dry rot treatment. You might decide that you don’t want to proceed with the sale, or you may want to renegotiate with the seller.


Dry rot is one of those terms that send buyers and sellers into a panic. Dry rot is not good news, but there are ways to treat and manage the problem. If you spot signs of dry rot in your home, or your house survey flags issues, seek expert advice.


Author: Chris Bloor MSc MRICS is a chartered surveyor and RICS Registered Valuer as well as being the founder and Managing Director of CJ Bloor Property Consultants – a property consultancy based in the Northwest of England. Prior to establishing CJ Bloor in 2019, Chris worked as a senior professional consultant in another firm of chartered surveyors based in Newton-le-Willows.