Damp Problems

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Damp on walls

Given the amount of rainwater we are subjected to in the UK, it is no surprise that many of us have experienced problems with damp walls. Whether it’s moisture entering the building via rising damp, damp patches caused by water ingress, or simple condensation, there are a variety of problems that can cause wet stains on your walls.

Our guide will discuss the causes of damp walls, how to identify them and the best methods of treatment. For specialist advice call your local branch or contact our damp proofing team using the button below.

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What causes damp problems on walls

Understanding the cause of your damp walls, black mould growth, or excess moisture in the home is key to identifying the correct form of treatment you require to resolve the problem. The most common causes are:

Signs of rising damp on wall

Damp walls caused by rising damp

Rising damp is caused by capillary action and only affects ground floor walls. The biggest sign is a “tide mark” of moisture above the skirting. Another common symptom is white marks left by hygroscopic salts drawn out of the brickwork. The salts and moisture often cause damage to plaster, peeling wallpaper, and a damp musty odour.

Damp walls caused by penetrating damp

Penetrating damp refers to moisture ingress through a lateral wall. It can affect walls at any level of a property. If water management systems like guttering or downpipes on the outside of your property look damaged or blocked then they are likely the source of the problem. Defective pointing on the external wall pebbledash or render and leaks in plumbing can also cause penetrating damp.

On internal walls, penetrating damp can create moisture patches. These can damage plaster, leave water marks and cause a damp musty smell.

Condensation symptoms on damp walls

Dampness caused by condensation will typically manifest as black mould spots on paintwork, wallpaper and around window frames. Condensation problems are more likely to occur on outside facing walls but can affect any cold surface in the property. Condensation and mould problems are more common in the autumn and winter months when people close their windows and increase the humidity and are particularly prevalent in bathrooms and kitchen walls.

Gallery of damp on internal and external walls

The images below show the different effects dampness can have on the walls of a property. Although humid patches on internal walls are a common symptom of most types of damp, other signs such as internal salt marks appearing on brickwork or plaster can be an indicator that rising damp is likely the cause of your worries. 

If you recognise any of the signs in the picture below then you may want to consider contacting us for some professional damp proofing advice.


Damp on walls

Damp on internal walls

All of the three main types of dampness can result in some similar symptoms such as paint cracking or deteriorating, or damp patches snd stains appearing on the wall. Thankfully, however, there are some specific traits to look out for to help you identify the type of damp in the property.

The appearance of black spot mould is usually a giveaway that condensation is the problem. While rising damp is commonly accompanied by a tide-mark that can reach anywhere from just above the skirting board to up to 1 metre in height across the affected area of the ground level wall.

Meanwhile, water ingress can appear at any level of the house, accompanied by a corresponding defect on the external side allowing the water to penetrate through to the inside wall.

Damp signs on external walls

Damp stains will often display on external walls as well. In the same way that tidemarks display on the inside of the home, they will often be present on the external side of the property too.

Penetrating damp will frequently result in moss or vegetation growing on or around the source of the water ingress on the exterior of the building.

You may also be able to see salts that have been present either in groundwater or the building materials become visible on exterior walls.

How to treat damp on internal walls

Damp is one of the most unpleasant problems a property owner can encounter. Damp problems can make a property feel miserable and ugly. If they are left to fester they can lead to structural problems and potentially costly repairs.

Whether in old buildings or new properties, to fix the problem and repair your walls it is essential that you apply the right form of treatment. If you can identify the type of damp you have from the list above, then you can see the most popular form of treatment for each below:

  • Rising damp problems - The most popular solution is to install a water repellent remedial damp proof course (DPC). This involves injecting a damp proofing cream into the mortar bed of the ground floor wall. After replastering the DPC is invisible.
  • Penetrating damp - The first step is to repair the fault in the building that is allowing the water ingress and then you can deal with any damp issue or related problems like wet or dry rot on the internal side of the property. Occasionally this involves installing damp proof membrane to affected areas.
  • Condensation patches and mould on walls : Condensation problems are caused by a lack of ventilation, our dedicated page has a list of DIY and professional solutions you can use.

You can read more about installing a damp course and the different forms of damp treatment available using the buttons below.

Does cavity wall insulation cause damp?

Many properties in the UK have cavity wall insulation, and while it is perfectly functional most of the time, certain circumstances can lead to a link between cavity wall insulation and penetrating damp.

To find out more about damp problems created by poorly or innapropriately installed cavity wall insulation you can visit our dedicated damp and insulation page.

Cleaning the house after repairing damp walls

Fixing damp problems caused by rising damp, penetrating damp or even condensation, will often necessitate that our specialist team have to drill through brick and mortar walls or hack off sections of plaster.

To ensure that we leave your home in walk-in condition after any treatment, our teams are equipped with top of the range Hilti dust extraction units to minimise the amount of dust created during these installations.

Contact us to treat your damp walls

If you are considering damp proofing walls in your property, we would always recommend a damp survey from a qualified professional. Our surveyors are experienced, CSRT certified and their damp proofing techniques are backed by the accreditation of Which? Trusted Traders and more. The surveyor will draft a custom treatment proposal for you and if you are happy to go ahead then we have a team of local technicians ready to get started installing your damp treatment.

To speak to a Peter Cox damp specialist, call your local team today. Alternatively, if you would rather contact us online then you can do so using the button below.

Book a Survey Online for a £25 Discount

Next Steps

*Survey enquiries for your local branch will be directed to our dedicated central survey control teams across the UK. Calls to 0800 and 0808 numbers are free unless you are calling from a business phone, in which case the rate will be set by your provider.