Damp vs. Condensation: Identifying & Solving

We're pleased to welcome our partners Cosey Homes Chartered Surveyors to share their knowledge about the difference between condensation and damp, so you can spot the signs for yourself. If you're concerned about the standard of a property you're thinking of buying, especially with regards to damp, be sure to make your surveyor aware.



Dampness in buildings can be divided into three distinct types:

 

1. Rising Damp
2. Condensation
3. Penetrating damp

Rising damp 

Moisture from the ground rises through the small pores within the brick at ground level. This type of moisture creeps up the wall through a force known as ‘capillary action’. The best way to understand this is to imagine placing a sponge on a wet surface and watch the water creeping up the sponge against the gravitational force.

Bricks may look solid enough, nevertheless at closer inspection a brick is full of voids. At the same time the moisture is creeping up the brickwork the gravity is trying to pull the moisture back down. A fight between these two forces is very predictable though because the state of cease fire always occurs around 3 feet from ground level where both forces exhaust themselves.

This tells us there is no such thing as rising damp above approximately 3 feet, so if you find damp on walls at higher levels then you should be looking for other explanations.

Condensation 

This occurs in every building from time to time for example; every time you turn the kettle on as you are pumping moisture into the room. The same is true for cooking, running the hot water tap and all the normal everyday activities within a house. The guiltiest piece of equipment is probably the dryer. The lack of insulation, single glazing, the absence of extractor fans and background ventilation all contribute to condensation.

It is fair to say that if condensation rather than rising damp is responsible for causing dampness, then the moisture readings should be almost the same on all walls regardless of its height from the ground. If the moisture reading shows a higher level at 3 feet or below, then you are probably looking at rising damp.

Penetrating damp 

This type of damp can be found mainly on first floor ceilings and on the internal face of the external walls. Penetrating damp is rain water somehow finding its way into the building (except for leaks from internal pipes).

Solid brick walls allow so much moisture into the building depending on the density of the wall and strength of the mortar pointing. Moisture is likely to get into the property through perished and weak mortar pointing rather than the actual brick itself. Penetrating damp could also be the result of leaky gutters, broken tiles or defective flashing.

Therefore, when buying or moving home its always worth getting a Homebuyer or Building Survey done by a RICS regulated firm, the reports will highlight any damp issues and recommend if further investigations need to be done by a damp specialist.


Cosey Homes are a RICS regulated professional practice with a team of highly skilled Chartered Surveyors, structural engineers and building engineers. Their head office is in St Helens, Merseyside and they operate nationally across the UK.