So, if you have a damp problem, get a damp specialist to survey your home as soon as possible. They’ll be able to diagnose the cause of damp and help you successfully treat the problem. It may turn out that you need a damp-proof course (abbreviated as DPC) installed in your home. Before you jump in the deep end, however, you should know exactly what a damp proofing course is.
What is a DPC?
A Damp Proof Course is a type of barrier (made of solid material or produced via chemical injection) designed to span across the length or width of your walls to prevent the onset of rising or penetrating damp. There are three main types of DPC to choose from:
- Solid DPC – a solid DPC is a horizontal or vertical barrier, usually made of some kind of waterproof material (such as bituminous felt, copper sheet or polythene) raised above the damaged wall, designed to divert rainwater and prevent the absorption of moisture and most specifically the onset of rising damp. It is usually fitted at least 150mm or six inches above ground level (in accordance with the British Standard Code of Practice for Instillation of Damp-Proof Courses BS 6576:1985). Solid DPC’s are considered the most reliable form of preventing groundwater ingress, but are really only suitable for newly erected walls; fitting them onto already built walls adds the risk of cutting through pipe-work or wiring, which could cost you more money later on.
- Chemical DPC – a chemical damp proof course, also known as a DPC injection or DPC injection cream, is specifically designed for walls that weren’t pre-treated with waterproof chemicals and are therefore more vulnerable to damp. It involves the ‘injection’ of an environmentally friendly, easy-to-use silicone based liquid (or ‘chemical cream’) straight into the affected wall to help fight off excess moisture.
- Osmotic Electric Treatment – this involves inserting special wires (usually titanium cathodes and anodes) into the wall to temporarily provide a heat-source that will dry out any lingering moisture. Power is drawn from the main household source via a 13-amp socket and the entire system is professionally ‘earthed’. This treatment can take time and is often quite expensive – but generally it’s the most effective for extreme cases of damp.
Do I need a DPC?
Just because you’ve spotted mould or the first signs of damp in your home doesn’t necessarily mean you will require a damp proof course or injection. Sometimes ‘surface mould’ can be cleaned away by hand before it sets in, and sometimes only a small portion of old plaster might need replacing, rather than an injection of the entire wall. To assess whether or not you need a DPC injection you can contact a damp proofing specialist.
You may want to hire someone who belongs to the Property Care Association (PCA) for free advice, or hire an inspector affiliated with the Certified Surveyors in Remedial Treatment (CSRT) or the British Wood Preserving and Damp-Proofing Association (BWPDA) – the latter will charge for a preliminary survey, but if it solves the problem quickly it can still help you save a lot on unnecessary spending.
How much is a Damp Proof Course?
The cost of a DPC depends on a number of different factors, including the type and extent of the damage that requires treatment, and the type of DPC you require (solid, chemical or electric). As a result, prices can’t really be generalised, and you are best off getting in touch with companies and potential contractors for free quotes rather than making obscure speculations.