The term “rising damp” describes the process whereby ground water is drawn upwards through the mortar and masonry of a building by means of capillary action. Porous building materials such as bricks and sandstone are the most likely to be affected.
All building materials have complex pore structures and the smaller the pores, the higher the water can rise. This moisture often brings groundwater salts and other contaminants with it, and these deteriorate building materials and decorative fixtures and fittings.
In most cases rising damp is a slow process and may be present in a building for several years before any signs of a problem appear. The speed at which the moisture rises up the walls will depend on several factors including:
Ultimately there are only a few property problems that can result in rising damp. If your home has a damaged damp proof course, no damp proof course or the damp proof course has been bridged by the raising of external soil or the build up of debri in a cavity wall, then rising damp is a possibility. If none of these sounds likely, but you still have damp problems then it is more likely that your property is suffering from penetrating damp or condensation.
Many properties have a slate or bitumen membrane barrier installed approximately 150mm (6in) above ground level in the ground floor section of the wall to prevent rising damp. This is called a Damp Proof Course or DPC for short.
Unfortunately, these DPC’s can fail due to age, deterioration, or damage caused by factors like subsidence. Modifications to a building like an extension or conservatory that have been built without a damp proof course also increase the risk of rising damp.
A new installation like a flowerbed or new driveway can raise the ground level and bridge the DPC. Essentially this means that your rising damp barrier has been skipped over and the groundwater now has direct access through to the porous building materials straight into your home again.
Damp proof courses can also be bridged if debri in a cavity wall piles up above the height of the course.
It can be difficult to identify rising damp because some of its symptoms are easily confused with those of other damp problems such as condensation or penetrating damp.
That said, you can look out for the following signs that are typical of a rising damp problem:
The signs of rising damp listed above would typically be evident to a height of about 1 metre (3.3 feet) from the ground.
Treating rising damp can be a tricky task to take on independently due to the various potential causes and the accuracy with which the treatment must be applied to be effective. This is why we provide specialist rising damp solutions that are covered by a 30-year guarantee which can be passed on to future owners of the property for complete peace of mind.
The steps below cover what you can expect from rising damp treatment by Rentokil Property Care:
Rising damp survey - Using their extensive experience and expertise, a Rentokil surveyor will carry out a detailed survey to pin-point the most appropriate rising damp treatment for your property. This plan will include some combination of the treatment options below...
Install a remedial damp proof course - Dependant on the thickness of the walls, holes are drilled in the mortar/brick to a pre-determined depth and at the correct level and spacing. These holes are then injected with a low odour water based silicone damp proofing fluid (damp proof course) to reduce the movement of water through the capillaries.
Repair or replace a damp-proof membrane - Damp proof membranes can also be used in rising damp treatment. These membranes can be installed immediately after the injection or repair of a damp proof course and used as a key for any new plaster. The membrane will separate any new plaster from existing salts and other contaminants on walls.
Re-plastering - Once our team has completed treating your home for rising damp our technician will ensure any treated walls are re-plastered with a waterproof additive.
Most property owners identify a rising damp problem when they spot damp patches on their internal walls. Before any treatment for rising damp on internal walls can start, technicians will need to lift skirting boards around the affected area and remove any plaster that has been contaminated by hygroscopic salts.
Rising damp problems caused by elevated ground levels can often be solved by simply removing excess soil back below the damp-proof course - this would be the case if a raised flower bed was the culprit for example. When a more permanent fixture or alteration has bridged the damp proof course, a damp proofing solution that adapts to your property will likely be required. A qualified surveyor will be able to make the best recommendation.
Discover more about our cost efficient, fast acting, and long term guarantee backed damp proof injection solution.
There is a school of thought out there that suggests rising damp is a myth, this is simply not true. Water rising through porous stone and brick via capillary action has been observed for centuries and is easily replicated by putting common building materials into water.
The reason there is controversy around rising damp is due to the high number of tradespeople who lack the experience and qualifications to correctly diagnose and treat this damp problem.
When other problems like condensation or penetrating damp are treated as though they are rising damp it is inevitable that the treatment fails and the property suffers.
So, it goes without saying that where rising damp is the genuine cause of the damp problems in your property it requires a survey and treatment plan from qualified professionals.
If you are interested in a property that has rising damp listed on the home report it is certainly something you should have surveyed. The qualified and experienced surveyors at Rentokil Property Care will be able to establish why the rising damp is occurring and the best form of treatment to stop it.
Providing all of our customers with the highest quality of service is our highest priority. This is why we ensure all our surveyors are Certificated Surveyors in Remedial Treatment (CSRT) and our technicians are trained to Property Care Association (PCA) standards.
Our team of experts will assess and correctly diagnose the extent of your rising damp issue. From this, we provide recommendations on specific damp proof treatments for the most effective ways to treat your problem. You can contact our expert team at Rentokil Property Care today on 0800 0121 437 or click the button below to book a survey online.