Damp Proofing Explained

Have you ever wondered what the holes in the lower level of bricks are on some properties? And, if you are buying a home that has these holes - usually two per brick along the length of the building - is it something that should be cause for concern?

The immediate answer is “no”, although there are some caveats that we'll come on to.

Older properties were built without a damp-proof course, which is a thick membrane on one of the lower level courses of bricks, which prevents moisture from the foundation soil rising through the structure. This means that, without adequate ventilation or other preventative measures, the property will be susceptible to problems with damp.

This is usually identified on the outside by growths of mosses and lichens and other plants that like shade and a lot of moisture. On the inside, damp patches can appear on the walls, with a rusty brown staining being common, which will need more than a simple coat of paint to eradicate.

One of the remedies in such situations is for the installation of a treatment known as a Chemical Damp-Proof Course Injection. A specialist firm drills these holes in the wall, inserting nozzles into them and injecting a special chemical formula, which spreads through the cavity and the active ingredients in the damp-proofing penetrate the substrate of the building. The chemical lines the capillaries in the construction material, giving a tough barrier for moisture and effectively operating in the same way as the damp-proof course membrane in more modern buildings.

The holes that have been drilled are either filled with specially-made plugs or a concrete filler (both of which can be seen in our picture). If the injection of the special chemical has been done properly, the effectiveness should last for between 20 and 30 years, since it is subject to the natural wear and tear of its environment.

From a dampness perspective, the effectiveness of the treatment will be obvious from the signs of any dampness that can be seen on the walls inside. The reason for getting a reputable firm involved is not only the amount of mess involved with the drilling but also the knowledge of the right constitution of the chemicals to be used, which are dependent on the suitability of the construction material into which it is injected.

When it comes to buying a home, you'll want to know if there is any evidence of problems with damp and, where there is a membranous or chemically-injected damp-course in place, how effective it is in stopping the damp from rising up through capillary action.

That is why it is so important to order a suitable survey, so that a qualified and experienced chartered surveyor can analyse the condition of the property you are thinking of buying, an assessment which will cover investigations into the handling of dampness and the extent of any damage identified that's been caused by dampness.

If you are looking to buy your next property, it makes good financial sense to take out a survey so that you know exactly what you can expect in taking your plans forward - and perhaps use the information to reopen negotiations with the seller if there is something critical identified. At Surveyor Local, we only work with chartered surveyors who are members of the Royal Institution of Chartered Surveyors, ensuring the survey you get is always professionally delivered.
They will work hard to identify all kinds of problems, including the impact of prior flooding on the structure of the property.
Call to get your no-obligation survey quote started, or to discuss your concerns with the acquisition of your planned property.
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