Rising Damp Treatment

Rising Damp Treatment in the South West

Rising damp is not the most common form of damp in buildings. It’s surprisingly rare compared to issues such as excess condensation.

If left untreated, rising damp can lead to decorative damage such as peeling wallpaper and blistering paint, breakdown of masonry due to salt contamination, and increased heat loss as damp walls lose insulating performance.

Where rising damp is suspected, our team at Biocraft South West provide expert damp surveys and inspections, followed by tailored damp proofing solutions to identify the cause and protect your property long-term.

Contact our team today – we’re always happy to help.

Worried about rising damp? Contact us and we’ll deliver safe, effective, and long-lasting damp-proofing solutions for your home.

What Causes Rising Damp?

Rising damp commonly occurs when moisture from the ground is sucked into the porous building materials from which walls are constructed through a process known as capillarity.

The potential height, to which moisture can rise in a masonry wall, largely depends on the absorbency of the components from which the wall is constructed. The pore structure of certain types of materials such as lime mortars can result in a high degree of absorbency and therefore are likely to be more susceptible to rising damp.

The flow rate of water through the structure is largely dependent on the pore size, shape and connectivity. The pore size in brick/mortar can be as small as 0.001mm radius, which in turn provides us a theoretical height of rise of around 1.5m high. Therefore rising damp can be found to have risen well in excess of 1.0m, the height commonly claimed to be the maximum.

Hygroscopic Salts

Rising damp is inextricably linked with other forms of dampness, such as hygroscopic damp.

Subsequently, due to rising damp hygroscopic (moisture attracting) salts, such as Chloride and Nitrate contaminate the plasterwork. Once present in the fabric of the building they can result in dampness by attracting and absorbing moisture from the atmosphere.

When hygroscopic damp affects a wall it becomes a cause of dampness in its own right and can continue to be a persistent problem, even in the event that rising damp has been successfully rectified i.e. by installing a new chemical damp proof course (DPC). This is why it’s imperative to carry out specialist replastering as part of the treatment process.

What’s The Cure For Damp?

For successful treatment and eradication of rising damp you must first stop the source of dampness. This is commonly achieved by introducing a new chemical damp proof course into the base of the wall.

Following the installation of the damp proof course, it will then be necessary to replace the existing damp affected plaster internally with a new specialist cement-based render which will be suitable for use in damp conditions and subsequently hold back any residual moisture and hygroscopic salts that remain present within the wall structure, and will also prevent slats from migrating through to the surface of the new plaster.

To successfully prevent the progress of rising damp through a wall structure, it is necessary to have a suitable and effective damp proof course. A damp proof course is a horizontal barrier located at the base of the wall which in turn prevents the upward flow of moisture.

Many older buildings were constructed with a physical damp proof course; however the materials which were utilised in early 20^th century, such a pitch and bitumen were very thin and overtime would become brittle and deteriorate which in turn would lead to ineffective barrier against rising damp.

All Biocraft South West surveyors are CSRT and CSSW certified, possessing a wealth of expertise in industry standards.

Installing a new physical damp proof course into existing walls can be hazardous, expensive and not to mention impractical. Today the most practical and effective way to eliminate rising damp is to install a chemical damp proof course, commonly achieved by injecting thixotropic creams into the wall, which subsequently turns the existing mortar bed into a waterproof barrier.

The new chemical damp proof course should be installed no less than 150mm above external ground level in order alleviate the risk of splash back from the external surfaces which in turn could potentially lead to bridging of the damp proof course and subsequent low level penetrating damp.

When installing a new chemical damp proof course it is imperative that treatment is carried out in strict accordance with BS8215: 1991 Code of Practice for Design and Installation of Damp-Proof Courses in Masonry Construction.

Biocraft South West is an established damp proofing company, with extensive knowledge in the diagnosis and successful remedial measures proven to eliminate rising damp.

To arrange a survey of your property or for further information regarding remedial damp proofing, contact us today. We cover Wiltshire, Somerset, Oxfordshire and Gloucestershire.

Rising Damp FAQs:

Rising damp occurs when groundwater moves upward through walls, often caused by a missing or faulty damp-proof course. The location and height of the damp patches typically help identify whether the issue is penetrating or rising damp.

Penetrating damp happens when water enters a building from external sources, such as leaking roofs, damaged gutters, or cracks in walls. It usually affects walls and surfaces exposed to rainfall or moisture from outside.

No. Rising damp won’t disappear without professional treatment. Left untreated, it can damage plaster, paint, skirting boards, and structural elements.

Drying alone won’t fix the problem because the moisture source is groundwater. After professional treatment, walls can dry naturally with good ventilation, dehumidifiers, air circulation, and the removal of wall coverings.

Walls may take several months to fully dry, especially thick masonry. Avoid painting or decorating until the wall is completely dry to prevent trapped moisture.

Rising damp is permanently treated by addressing its source and protecting the walls from further moisture. Professional solutions typically include:

Chemical damp-proof course (DPC): A water-repellent cream is injected into the wall mortar, creating a barrier that stops groundwater from rising.
Physical DPC installation: A solid membrane can be inserted into the wall to provide a long-term waterproof barrier.
Tanking and replastering: Walls may be coated with a waterproof slurry and replastered using salt-retardant or breathable materials.
External adjustments: High ground levels or poor drainage around the property may be corrected to prevent water from bypassing the DPC.

After treatment, walls are allowed to dry naturally. Ventilation, dehumidifiers, and air circulation can help speed up the drying process. Professional treatment ensures lasting results and prevents structural or cosmetic damage caused by rising damp.