The UK is no stranger to rain which is why efficient damp-proofing is essential

Depending on your age, the words ‘rising damp’ may conjure up images of Rigsby and Miss Jones in the hit TV series of the same name or, more likely, will have you fretting about ruined walls and another expensive household problem that needs fixing.

While it’s a problem that’s easily avoided, once you have rising damp, it can be costly to put right. It can usually be spotted at the bottom of walls and occurs when water from the ground is being sucked up by the masonry above. Visible water stains will make the problem obvious, as do ruined paintwork or wallpaper.

The most frequent cause is a lack of damp-proof course in the wall or floor – maybe because the house was built without one. Or it could be that the existing damp-proof course has broken down, been damaged or has been covered over by wall finishes, solid floors, soil or pathways. You may well have to splash out to install a new damp course but before you commit to this, call in a surveyor who will be able to recognise the problem and advise you on your
best course of action.

What is it?
A damp-proof course (DPC) is a physical barrier inserted into the fabric of a building to stop water passing from one place to another. It can be horizontal (preventing water from the ground being sucked up by the dry masonry above), or vertical (to stop water passing from the outside of a building, though the masonry, to the inside).

One of the earliest forms of damp proofing was the addition of a layer of slate during a building’s construction. While this method is still used today, the less expensive plastic version is more popular. A horizontal damp-proof course is usually placed six inches above ground level and used in conjunction with a damp-proof membrane, which stops water rising to any part of the ground floor from the ground. In many older properties a non-porous stone was used to build the first few courses of masonry. However, over the years, this stone can become porous allowing water to soak through.

Practically, removing a course of stone to place a plastic, lead or slate DPC in the wall is not a viable option, which is why new methods have been found. These generally require an injection of chemicals into the walls and, on a larger scale, should be done by specialists as complications can arise as a result of saturated plaster and the measurement of the chemical being injected.

Work it out
Installing a damp-proof course will involve some upheaval in your home as it is likely to mean lifting up flooring inside, which could mean kitchen units or bathroom appliances will have to be taken out for the work to be completed and plaster hacked off the walls. You will then have to pay for replastering and redecorating, too, once the job is done. You are looking at a few thousand pounds to get a professional to install a DPC, but treatments should last about 20 years. To find a reputable damp - proof expert visit the Property Care Association website (www.property-care.org). All members are accredited for quality of work and it will direct you to reputable companies that operate within your area.

A green solution
Holland Damp Proofing managing director Evert De Graaf talks about its green damp-proofing system.
Holland Damp Proofing offers an environmentally friendly way of damp- proofing your home.

How does it work? ‘It uses airflow to dry out walls, rather than toxic chemicals, which are used to install traditional damp proofing systems. It is a permanent solution, guaranteed for 20 years, so it won’t need replacing like normal damp-proofing often does after five to eight years.’

Why is it effective?
‘The system uses specially designed bricks to channel airflow, drying out the walls and removing the damp instead of trying to block it, which is how traditional damp-proofing works. Our system removes the damp so it won’t return. It also has the added effect of preventing wet and dry rot.’ What are the advantages of using this system over more traditional chemical damp proofing methods? ‘The airflow method is very effective and, unlike traditional damp-proofing, there are no toxic fumes. Installing traditional chemical damp-proof courses usually means that inside walls will need replastering because all old plaster has to be removed to a minimum height of one metre from the floor level. That means that if there is a kitchen or bathroom fitted against the wall it will need to be taken out. The Holland Damp Proof System is installed in the outside walls so there’s no need to replaster inside, and consequently there’s no mess either.’

What sort of houses is it suitable for? ‘Virtually all types. It is suitable for use on cavity, solid, brick and stone walls. It is particularly good for stone walls. Normal damp-proofing often has little or no effect because of the gaps between the stone, but our system works because it dries out the damp.’Is it a big job to install? ‘Because we work from the outside, the inside of your house won’t be turned into a building site and, with our trained engineers doing the installation, it only takes one to two days.’

What are the cost implications of installing an environmentally friendly DPC in your home, as opposed to the more traditional method? ‘The two are usually around the same but, with our method, you won’t have to pay to redecorate or have your kitchen or bathroom floor replaced, which makes us cheaper. Also, in the long-term we are much more cost effective because our DPC lasts longer and won’t need redoing for at least 20 years.’ For more information on the Holland Damp Proof System, go to www.dampproofing.com

Pictures: getty images