A Guide to Damp Proofing Your Home

It’s supposed to be summer, but looking out of the window in front of my workstation at the driving rain tells a different story. Unpredictable and heavy rainfall seems to be becoming more prevalent and heightens the need to address damp proofing issues in many of our homes before damp sets in and costly repair and refurbishment will become a reality. Most of us have heard the term damp-proofing but it is a much misunderstood practice, so let’s take a look at how to go about damp-proofing your home.


The quick answer is – rising damp. This results from capillary action as ground water rises up through the fissures and pores in the walls of bricks and mortar buildings. In order to prevent this a horizontal damp-proof course is installed into the walls over 6 inches above ground level to ensure that rainwater does not splash over it. Another vertical damp proof course or membrane should always be added to walls that are abutted by unprotected walls. Damp proofing was not common practice until the 1950s, leaving many older properties unprotected.

Various types of damp-proof courses

There are a variety of types of damp-proof courses, each with pros and cons. The type of damp-proofing you choose will reflect your particular property, budget, climate and personal preference.


Choosing a chemical damp-proof course is ideal if you are after a less intrusive preventative solution to damp. This method involves the injection of silicone-based liquid into walls at a suitable height, creating a water-repellent layer. While it is undoubtedly the least invasive method, it can be a variably effective solution as it the silicone does not always pass through walls in an even manner and can leave holes that let water through. However, recent developments have led to cream chemical damp-proofing, which gives a far better consistency in results. It is also worth noting that liquid damp-proof courses will not work in non-porous walls, such as those constructed with breeze blocks.


This is the traditional method, in which waterproof materials including copper or polythene sheeting is introduced into the wall at a suitable height, forming a layer. This is the most reliable method, but risky in existing walls as the process of grinding out the mortar can weaken walls and there is the risk of cutting through pipes and electrical wiring. This, therefore is best left for new walls. Electro-Osmotic Damp Proof Course


Titanium electrodes inserted into the wall so that the negative cathode (attracting water) is at the bottom, meaning water’s natural proclivity to rising through the wall is reversed. This is relatively costly, but extremely effective. You end up with a power unit, plugged in and maintaining small electrical charges into the masonry. This method is often used in walls of apartments to solve damp issues in the building.

In addition to these ‘ultimate’ solutions to damp proofing, it is worth noting that the following three hacks can really help.

  • Run extractor fans in kitchens and bathroom, during and after use
  • Keep home above 17 degrees at night in winter
  • Open windows regularly during drier months.