What is a damp proof course?

A damp proof course (DPC) is a form of damp proofing installed in a property to prevent rising damp and associated problems. There are various methods to install a DPC so our guide will help you to understand the different types of damp proof course available,why a DPC might fail, and how to fix a broken DPC.   

If you are worried that your damp proof course has failed or if you have spotted the signs of rising damp in your home, then our specialists surveyors are on hand to attend the property to diagnose the issue and get started on a treatment plan for you.

Simply put, homes that do not have appropriate damp proofing measures installed are more likely to take on excess moisture. A functioning damp course is an essential part of any property in order to prevent moisture from the earth and soil rising up the walls through capillary action (also known as rising damp) and  damaging the property as a result.
 
A broken or missing DPC will result in problems such as damp walls on both the internal and external sides of the home, and without treatment to correct this, rising damp problems can deteriorate into destructive wet rot and dry rot issues.

Thankfully there are a number of damp proof course solutions available so that whatever the underlying cause of your rising damp problem, we have an effective solution for any type of property.

This is the most common solution to solve rising damp caused by a failed or broken damp proof course. Sometimes called a ‘remedial’ damp proof course, this process involves the injection of a ‘damp proof cream’ made from a silicone-based liquid that reacts with the silica in the masonry to produce a water-repelling layer within the wall.

The damp proof injection is applied at no less than 150mm from the base of the wall and is often a more practical solution than other “solid” damp proof courses.

Another option for resolving damp problems, particularly when dealing with thicker stone rubble filled walls would be our Electro Osmotic solution. With this damp treatment, any water rising up through your wall is driven back down to the ground with a positive electric charge. They are widely used in historic and older buildings.

Damp proof membranes can be used to form part of a damp proof course. The damp proof membrane is positioned underneath a concrete slab with the intention of protecting the concrete from any moisture and therefore making it damp proof.

This form of damp proofing is often used to protect properties from penetrating damp problems when the home has earth retaining walls.

A damp proof course is a typical feature of most contemporary properties. Generally during the construction of the property, there will be a mortar course with a damp proof material inserted into the structure just slightly above ground level.

These in-built damp proof courses are usually very effective, however, the widespread use of DPC’s only came about in the 1920s. As a great number of houses in the UK are older than this, so it is possible that your property does not have a damp proof course. If your property was built after 1920 it is also possible that your current damp proof course has weakened and failed over time to allow water ingress and potential rising damp problems.

There are many reasons a damp proof course can fail. Some of the most common include: subsidence causing the building to move - creating a break in the original DPC, building renovations that raise the ground level above the current damp proof course, and breakdown due to age and deterioration.

In circumstances such as this, we would always recommend a professional inspection of the faulty damp proof course to evaluate any necessary repairs.

We understand the need to feel confident and secure in the knowledge that once installed, your damp proof course will continue working to prevent rising damp recurring in the property. That is why any damp proof course treatment provided by our team is backed by a long lasting guarantee of up to 25 years, providing you with complete peace of mind and reassurance that in the unlikely event of something going wrong then we will be there to put it right.