Audrey
Are you considering getting a damp proof course for your home? Have you started to notice damp problems around the property? Here’s what you need to know about damp proof courses.
What is a damp proof course?
A damp proof course works as a protective barrier against rising damp issues in properties. A good damp proof course can save homeowners and property management organizations lots of money by preventing damp related damage which can add value to a home. The damp proof course works as a literal barrier, preventing rising damp from travelling up the property, and is installed on the ground level to protect everything above.
Most properties will have been built with an existing damp proof course, but sometimes these expire. In which case, a new damp proof course will be needed to replace the original damp proof course.
There are two main types of damp proof course: chemical damp proofing and electro osmotic damp proofing. The former is the most common, and involves injecting a solution into your walls to create a barrier and damp proof your home. Electro osmotic damp courses are less common, and work by using electrical currents and to prevent a movement known as capillary action.
How do you know if you have a damp proof course?
According to Drycore the original damp proof course used during construction will usually consist of a large, visible protective barrier in the form of a large plastic strip. This will generally be sandwiched between bricks a few rows up from the ground. This method of damp proofing has been around since the 1970s and is considered to be effective against most rising damp on ground level properties.
In older properties, you may not be able to tell if you have existing damp proofing, as the method prior to this was engineered using brick, slate or bitumen and mortar. This method was also generally considered ineffective, as the damp proof membrane was not guaranteed to work. Should your property have this kind of damp course, you will likely need to install a new one to protect your interior walls from damp rising.
Will a damp proof course stop rising damp?
So long as a damp proof course is installed correctly, it should be an effective method of damp proofing. Most homeowners find that chemical damp proofing works very well when it comes to forming a damp proof membrane. If you’re looking for effective results from your damp proofing, it’s important to make sure the job is done correctly in order to prevent moisture and penetrating damp, though, as otherwise you may still suffer with damp issues.
How long will a chemical damp proof course last?
If correctly installed, chemical damp proofing can last as long as 20 years. Some professionals may even provide a 20 year guarantee with their work to ensure your property’s safety from moisture.
How long will electro osmotic damp proof courses last?
There is no specific lifespan for electro osmotic damp proofing, but many professional installers will provide a 10 year guarantee with their product.
How do I know if I need a damp proof course?
As mentioned above, older properties that have not recently had a damp proof course installed are likely to benefit from some form of damp proofing. This is especially important if the property is on the ground level or in a particularly damp area.
You might also need a damp course if you begin to notice what might look like a tide mark on your walls. You may see your paint beginning to gain texture or flaking from the wall, and may also notice a sudden prevalence of mould or mildew. All of these are signs of moisture rising through your property and causing a damp problem.
If you choose to leave these, your home may develop issues with its structural integrity and, in some situations, you may experience dry rot. Rising damp can be really detrimental to properties, and so it’s very important if you’ve not got a damp course to get one as soon as possible! Chemical DPC injections are a great option for those who need a new damp proof course, as they are installed through small halls in the wall behind the skirting boards, meaning there is minimal upheaval.
What can cause a damp course to fail?
According to Damp Hero if a damp proof course has not been installed correctly, it is less likely to be successful or to last the full 20 years. After having the damp proof course installed, owners will need to re-render external walls around the course, too, otherwise there is the risk of existing moisture above the damp proof course causing damp problems, which the chemical damp proofing course cannot tackle.
How much will a damp proof course cost?
The cost of a damp proof course will depend on a number of things. It will depend on the size of the property, where the issues with damp are, and which type of damp proof course you opt for.
For an initial damp survey, you can expect to pay between £100 and £200. This will allow you to pinpoint the exact issue, making it easier to target the damp issue with an effective water repellent barrier.
From there, you can expect to pay from £100 per meter of wall treated with a chemical dpc for interior walls. For exterior walls you will need to budget for more than this, as you may have to also dig gravel out or remove soil.
To find out exactly how much your damp proof membrane installation will cost, you will need to contact a professional, as each property will have different needs and subsequently different costs.
