In the simplest terms, damp is the presence of moisture that has built up within a property. On the surface, this may not sound all too serious, however if left untreated and allowed to persist, damp can cause major structural damage and even cause health problems. There are three main types of damp: rising, penetrating and condensation. Each type can vary in severity and has different causes.

Rising Damp:

Rising damp is a result of moisture rising from the ground and up into the building. This can be prevented if a Damp Proof Course (DPC) is in place in the building, however if this is absent, or it has been compromised, moisture can rise into the walls up to a level of 1 meter. Most properties built from the 1980s onwards are fitted with DPC and it is mandatory for all new-builds, however older properties, especially ones from Victorian and Edwardian eras are susceptible, regardless of location.

You can identify rising damp as it will appear as wet looking stains on the lower sections of walls. If left untreated, rising damp can cause serious structural damage to walls. The cost of installing DPC is therefore just a fraction of what it would cost if you had to undertake repairs to the structure of the property.

Penetrating Damp:

This is caused by moisture penetrating the walls from the side. For example, a leaking gutter splashing water onto the side of the property or driving rain could result in penetrating damp.

This type of damp might generally be found higher up the walls than rising damp and will look like wet patches. Unlike rising damp which moves vertically, penetrating damps tends to move horizontally. More serious cases can appear as black marks, sometimes with mould growing off it.

If caught early, repair costs can be minimal however if left untreated it can become very costly.


Arguably the most common type of damp, condensation is the result of water vapour and warmer air condensing on colder surfaces. It is more prevalent during the colder months due to difference in temperature between the air, windows and walls.

It usually appears as mould and water droplets on window frames and doors. Condensation is easier to deal with than more ingrained damp and can be wiped away with a cloth and anti-mould cleaning products. To prevent it, you can buy dehumidifiers that suck moisture out of the air and prevent it condensing on surfaces.

So how serious can it be?

As previously mentioned, if dealt with early on, damp can just be an inconvenience, however if left to fester, damp can damage the structure of the property and cause serious health issues. A knock-on effect can be rotting timbers. Dry rot specifically can be serious, causing timber to become dry, brittle and structurally useless. It can result in wide damage that can penetrate bricks and mortar.

The mould produces allergens, irritants and sometimes toxic substances. It can lead to asthma, allergic reactions, reduced lung function and even depression.

Prices for fixing damp in general can range from the hundreds to the thousands.

Can damp affect the sale of my house?

Unfortunately, damp can have a big impact when it comes to selling your house. It can lower the value of your property and make it more likely that you will receive lower offers. If it is noticeable to buyers who view your property, it could completely put them off.

Even after an offer has been accepted, a buyer may use it to try and knock down their offer if they’ve had a surveyor’s report that has highlighted damp. If serious enough and where it has affected the structure of the property, mortgage lenders may refuse to lend, and it could result in a sale falling through.

What are the best preventative measures?

There are a few home improvements which can help mitigate the emergence of damp.

Double glazing can help reduce condensation by increasing the temperature of windows inside. Extractor fans help remove warmer air and water vapour from rooms, and as previously mentioned, Damp Proof Courses can prevent rising and penetrating damp building up. DPC will vary in cost depending on the supplier and the property involved, however you can expect to spend approximately £80 per meter of wall, or about £300 per wall. A more cost-effective measure, simply opening the windows, will also help by increasing the airflow inside the property.

It can often be hard to identify damp, especially if hidden behind appliances or furniture. The best preventative measure is, therefore, to have a detailed report carried out by a property surveyor who can assess the extent of any damp and suggest the appropriate action going forward.

This article was written by a free online estate agent, House Sales Direct. If you are wondering “how can I sell my house fast?”, head to the House Sales Direct website for more information relating to all property-related enquiries.