Does Your London Home Need a Damp Assessment?

A damp assessment or a damp survey is something that is often done when you are considering buying or selling a property.  It is also a useful survey to have if you think that you may have a problem with damp in the property.  But what signs should you look for to indicate a survey might be needed?  And what happens during a survey?

Common types of damp

There are a number of ways that damp can affect a property and three that tend to be the most common – rising damp, penetrating damp and condensation.

Rising damp is where the moisture is absorbed from the ground and soaks into the bricks of the wall.  This is a normal process that is normally stopped by a damp proof course.  But if this is missing or broken, then the damp continues to rise to the internal areas of the house and causes damp.  Signs include peeling wallpaper and paint, damage to flooring and skirting boards and signs of black mould growing on lower wall areas.

Penetrating damp usually happens at the other end of the property – most commonly through broken tiles on the roof, broken guttering or cracked brickwork.  The water finds its way through the weakness to the internal areas of the house and causes damp patches, usually on the ceiling or the top of the walls.

Condensation is where warm moist air hits cold walls, releasing the moisture and causing condensation.  This is often caused due to poor ventilation with kitchens and bathrooms being the top causes.  Beads of water will appear on walls and on windows, even furniture if there is a condensation problem.

Problems caused by damp

While the look of damp patches is unsightly and can cause a problem with a sale if you are planning to sell the house, there are other bigger problems associated with damp that might mean you need a damp assessment.

For starters, damp allows black mould to grow and this can be a health risk.  It has been associated with problems such as asthma and respiratory conditions, making them worse.  The mould releases spores into the air and makes air quality poorer inside the house, meaning people breathe them in when they are in the house.

Dampness can also lead to fungal conditions that can cause serious problems.  Wet rot and its more dangerous relative dry rot can only thrive when conditions are damp enough and can cause serious damage to the house.  By effecting any wood in the structure, they can even cause the house to be unstable.

The damp assessment

When you need a damp assessment you should always look for an experienced and qualified damp expert to conduct the survey.  That way you know everything will be done to the highest standards.  

The assessment will start usually by looking at the basics of the property itself.  Things like the construction of the property, if it has cavity walls, rubble-filled or solid walls and if there is already a damp course in place are all important things to understand.

Looking at the surrounding land is also a part of the survey.  For example, if the land slopes towards the house, this can increase the amount of water that bricks are being bombarded with.  If the ground level has been raised in any areas since the house was built, this can compromise the damp proof course.

The external survey will also look at the typical causes of penetrating damp, such as blocked guttering, cracked roof tiles or problems with the render or brickwork.  Surface drains can also lead to problems if they are blocked and water cannot flow into them.  They may also cause water to pool against the house, causing rising damp issues.

Finally, ventilation will also be examined to see how air gets from inside the house to outside.  This might include vents or extractor fans in the kitchen and bathroom areas and looking to see if anything is blocking any vents – ivy growing up a wall is a common culprit.

Inside the house

The survey can then move to the internal areas of the house.  This will start with checking walls for obvious signs of damp such as black mould, tide marks or cracked or peeling wallpaper.  If there are any signs of visual dampness, and damp meters are used to find out just how much moisture is in the walls behind these signs.

Often if there were signs outside that could lead to damp, checks will be made in these areas to see if there are problems that haven’t caused visible signs yet.  A moisture profile will help to understand the problems within the property and outline what should be done.

Damp report

The damp report is the document produced after the assessment to help the homeowner understand what problems are affecting their home and what steps are needed to remedy them.  Recommendations can range from simple things such as removing plants from ventilation areas to allow better ventilation to the full-scale replacement of a damp proof course if this is malfunctioning.

Once you have received a damp survey, it is then up to the homeowner what to do with the recommendations.  Depending on the severity of the situation, work may be needed urgently or there may be some problems that are minor and can be done with a little less haste.  However, all issues that have or could lead to damp should always be dealt with as soon as possible.

If there are signs of serious conditions such as dry rot, then action will be needed immediately to prevent it from causing serious damage to the property and potentially leaving it uninhabitable.


A damp assessment or survey is a useful way to better understand damp problems in your property.  While they are often used around the selling of a property, if you think you may have damp in some form, then a survey is an ideal way to find out what the nature of the problems are and what should be done to deal with them.


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