Building Preservation

At Cook Group we have over 45 years experience in dealing with damp and timber problems in buildings. We work with all kinds of properties, new and old, as well as having a proven track record in treating historic buildings.

If you think your property is suffering from rising damp, penetrating damp, strange damp patches, salt crystals appearing through decorations, wood-boring insects, wet rot or dry rot or uneven and bouncy floors, we can advise you on the appropriate course of action.

If you are buying a property and are concerned about damp or timber problems, our unrivalled knowledge can enable you to make an informed decision or maybe even assist you in negotiating the purchase price.

For a small fee we will carry out a damp and timber survey during the sale or purchase of your property or new home, conducted by our qualified surveyors. All of our surveyors either have or are working towards the highly-regarded qualification ‘Certified Surveyor in Remedial Treatment’. All our surveys are covered by Professional Indemnity insurance too.

Estate agents and building professionals (such as chartered surveyors, architects, engineers etc) regularly refer customers to us: a testament to our excellent reputation.

All of the chemical treatments we use are as environmentally friendly and low odour as we can possibly make them.

And remember, when it comes to Building Preservation, the bottom line is we will give you the same service, professional work and advice, whatever the job’s requirements; a small damp patch or an entire building affected by rot.

© Copyright Cook Group Ltd


  • Rising Damp Technical Paper – This is our rising damp technical paper which tells you a bit about rising damp and how we treat it.

Types of Rot

Dry Rot

Dry Rot (Serpula Lacrymans) is a brown rot. The fundamental difference between True Dry Rot and all the other wood rots is that it has the ability to seek out new timber to attack through inorganic ‘barriers’ such as brick walls, underneath concrete etc.
The fungus is also able to control the moisture levels in any new timber it finds, so if the moisture content in a new piece of timber is too low the fungus will transfer moisture from its source to allow the fungus to thrive. Correspondingly if a piece of timber is too wet (i.e. there is not enough free oxygen inside the cells of the timber) the fungus will extract moisture from the timber to allow it to ‘consume’ it.
Severe structural damage to timbers in buildings can result and specialist treatments are always required.
The picture below shows a fruiting body growing through the wall string of a staircase, notice the red spore dust

Wet Rot

There are hundreds of different types of wet rot, and dozens that can affect buildings.
One of the most common by far is ‘cellar fungus’ (coniophera puteana), damp conditions under a floor of a property are ideal for this fungus.
The actual type or species of wet rot more often than not doesn’t actually make any difference to the treatment required.
Most cases of wet rot are treated in the same way.
Treatments usually rely on removing the source of moisture and the removing and replacing decayed timbers. Chemical treatments are not usually required. Replacement timbers are either pre-treated or treated on site, this is because it is not always possible to remove all moisture or the potential for moisture in an area of a building.


The first stage of dealing with any outbreak of dry rot is to carry out a survey of the affected area in the property. Initially to make sure it is dry rot!
The first thing and most important task is to identify the source of moisture for the outbreak and stop / control it.
Then we need to determine the full extent of the outbreak, this in itself can be a very difficult task and can usually only be done after you start stripping out the affected areas.
Once we know the full extent we can recommend a course of action to include the following
  • Steps to control the moisture or water ingress
  • The full extent of repairs & reinstatement works necessary
  • The extent and type of chemical treatments necessary


We use chemical treatments to help new timbers or remaining timbers withstand levels of residual moisture, which otherwise might restrict the reinstatement process.
Masonry sterilisation works are almost always carried out to ‘kill’ any of the remaining ’active’ outbreak

Building Preservation 9th January 2019