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What is a Damp Proof Course? Tackling Rising Damp

Dampness in buildings can cause structural damage and health risks. Moisture can infiltrate walls, floors, and foundations without a damp-proof course, creating damp patches, mould, and dry rot. This damages the building and makes residents sick. Preventing these issues and guaranteeing a building’s durability and habitability requires a properly installed and maintained, damp-proof membrane or damp-proof course or DPC. 

Buildings use damp-proof courses (DPCs) to keep moisture and Dampness from entering. It prevents rising Dampness, lateral wetness, and condensation. DPCs are put near ground level at the base of walls to prevent moisture from growing through walls.

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What is a Damp Proof Course?

A damp proof course (DPC) is a barrier added to the interior walls of your property to prevent rising damp, which occurs when water is soaked up from the ground through capillary action. It then begins to travel up the walls, floorboards, skirtings, and joists, causing plasterwork and timber to rot.

This protective layer is therefore typically installed in the lower parts of the walls to stop moisture from leaving mould to fester.

Damp proof courses are one of the most effective and popular forms of protection amongst our customers here at Advanced Damp, especially in properties where the existing barrier has failed to prevent moisture from rising. When installed properly by damp proofing experts, they can last for as long as 25 years!

Types of Damp Proof Course

Rising damp problems can be solved with one of three types of damp proof courses. The main remedial solutions that you have to choose from are therefore as follows:

  • Damp Proof Course Injection – This long-term treatment involves injecting a silicone-based cream straight into the wall via small holes, which are drilled around 150 mm above ground level. The cream then operates as a physical barrier against rising damp, therefore stopping it from working up the wall.
  • Electro Osmotic Damp Proof Course – A positive electrical current is run through the wall using copper and titanium wiring, which keeps rising damp below the course. We’d recommend this as an effective non-chemical option for older buildings with thicker wall structures, especially those filled with stone or rubble.
  • Damp Proof Membrane – Thin plastic sheeting creates a moisture-resistant barrier by being placed under a building’s concentre slab. Choose this physical damp proof course option to tackle moisture in properties with earth retaining walls.


Ultimately, the solution you select will depend on whether or not the property’s brickwork is suitable for a chemical damp proof course.

Get in touch with Advanced Damp and our experts will recommend the form of damp proof coursing that is best for your home or property. We have over 20 years of experience in dealing with damp, so let us help you make the right decision today.

Damp Injection
Damp Proof Membrane

What is a Damp Proof Course?

o protect and keep moisture out of walls, floors, and foundations, structures use damp-proof courses (DPCs). Its main function and property, the wall, is to block water and humidity from rising through the system or entering the wall from outside. A DPC wall also keeps the structure’s interior spaces dry and healthy by blocking moisture.

DPC materials (bitumen, PVC, chemical-based)

Distinct damp-proof course materials have different qualities, commercial properties and benefits:

  • Bitumen: Common DPCs employ a thick, waterproof asphalt membrane. They are water-resistant and temperature-resistant.
  • Polyvinyl chloride (PVC): DPCs are flexible, easy to install, and moisture-resistant. Rolls or sheets of PVC DPCs make application on various surfaces easy.
  • Chemical-based: Chemical DPCs inject or apply damp-proofing solutions or creams into building walls. These compounds react with brickwork to repel water. Chemical-based DPCs are utilised for building retrofits.


DPC material cost varies on building requirements, wetness, budget, and local construction rules. A damp-proofing cost specialist can help you choose the best DPC amount for your damp-proof membrane take-out project.

4 Benefits of Damp Proof Courses

Properties situated in wet and cold climates, especially those here in the UK, can benefit hugely from damp proofing as they are highly susceptible to damage caused by heavy rainfall. Here are some of the other reasons why damp proof courses are ideal for long-term moisture protection:

Stops Wet Rot

Wet rot typically grows in buildings with unprotected timber by feeding on moisture and nutrients. This fungus causes decay in everything from carpets to wallpaper, and can be stopped by treating the effective area.

However, installing a damp proof course also addresses the root cause of wet rot by preventing moisture ingress.

Prevents Structural Damage

Dry rot is another issue that damp can potentially cause and leads to crumbly timber. This is arguably even more serious than wet rot, as it spreads through interior spaces into neighbouring properties and harms the integrity of their core structure.

Damp proofing will stop this form of rot in its tracks and prevent it from weakening over time, so you can feel confident in the knowledge that your property will remain safe.

Keeps Inhabitants Healthy

Two of the biggest problems created by damp conditions are mould and mildew, which release toxins that can be incredibly harmful to your health.

You may therefore experience signs of an allergic reaction, including, wheezing, eye irritation, nasal congestion, and respiratory infections. These symptoms are especially dangerous for those with asthma or weakened immune systems, which is why effective damp proofing is so vital.

Enhances Property Appearance

It can be tempting to simply cover patches of mould or damp with paint to quickly get rid of the problem in your home. However, while this may offer a short-term solution for improving the appearance of walls, these patches will begin to break through again at some point.

A damp proof course can eliminate the issue of cracked paint, therefore leaving your walls with a much smoother canvas to paint over.

Maintaining a damp-free property can also be handy if you’re thinking of selling, by ensuring that it remains appealing to potential buyers and doesn’t lose any monetary value.

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Damp Proof Course Installation

The building must be assessed for its need before establishing a damp proof course (DPC). Consider the building’s age, construction materials, location, external ground level, and wetness. A competent damp proofing carried re-proofing specialist can assess the building renovation requirement for a DPC and recommend a solution.

DPC Installation (Injection, Insertion, Membrane)

Depending on the building and DPC, numerous damp-proof membranes, course full-proof and new damp-proof course installation procedures exist. Common damp course installation methods:

  • Injection: Drill holes in the walls and inject damp-proofing liquid or cream—the injected agent bonds with the porous material to prevent moisture.
  • Horizontal Installation: A DPC can sometimes be installed horizontally into walls above ground. A waterproof membrane or other suitable materials are placed in the wall structure during building or remodelling.
  • Waterproof Barrier Application: This method of retrofitting existing structures entails applying a waterproof barrier like bitumen or PVC sheet to the affected surfaces. It forms a continuous coating that keeps moisture out of walls.

The installation procedure relies on various types of dampness severity, accessibility, money, and what is a well-proofing course specialist’s advice. Each damp-proof installation method has pros and downsides, proof course, so examining the building’s needs is necessary.

DPC Installation Considerations

Planning is needed to retrofit existing damp walls and proof and proof courses in old buildings. Some key considerations:

  • Building Materials: Construction materials can affect DPC and installation procedures. Some materials need particular preparation before installation.
  • Disruption: DPC retrofitting may disturb building occupants. To minimise disruption, assess the impact on daily activities and plan accordingly.
  • Professional Help: DPC retrofitting is complicated and requires specialised equipment. We recommend hiring a damp-proofing specialist to install and use the DPC properly.

The installation process can be done efficiently to prevent rising dampness and reduce moisture by carefully assessing the need for a DPC, choosing the right installation technology, and considering the unique challenges of retrofitting in older buildings.

Damp Proof Course Failure Signs

An inefficient damp proof course (DPC) might show numerous indications of damp proof and damp course side problems. The symptoms may include:

  • Damp spots or stains on walls, ceilings, or flooring.
  • Deteriorating paint or wallpaper.
  • Damaged regions smell musty or damp
  • Growth of mould or mildew in corners or under furniture.
  • Salt deposits on walls or masonry are efflorescence.
  • Plaster or mortar crumbling.

These signs indicate moisture penetrating the ground-level DPC, causing Dampness in the ground-level building’s structure and interior and exterior walls. These indicators must be addressed immediately to avoid future harm and health risks.

Damp Proof Course
Maintaining A Damp Proof Course

Signs That Your Property Requires Damp Proofing

Unsure whether investing in a damp proof course is worthwhile? Here are some signs that your property may not be properly protected against rising damp:

  • Unpleasant musty smell
  • Peeling wallpaper
  • Crumbling brickwork
  • Visible black mould growth
  • Damp stains or dark patches
  • Dry rot on skirting boards
  • Tidemarks on walls caused by evaporation
  • Rusting iron

If you spot any of these signs, it’s crucial to contact a damp proofing specialist as soon as possible. The longer the problem goes untreated, the more time it has to progress into serious structural issues. So, contact Advanced Damp today to kickstart the process with a comprehensive damp survey.

Does My Home Have An Existing Damp Proof Course?

Many modern homes are protected by a damp proof membrane, which you can find at the bottom of the walls. Identifying this membrane is pretty simple; you should see a small plastic strip enclosed between two bricks, which indicates that the property is already designed to prevent rising damp.

However, your damp course may require re-rendering with sand and cement, along with a replastering additive, if it was installed more than 20 years ago. 

Although the course will successfully block any moisture from entering the property, it will not get rid of hygroscopic salts, which can suck more moisture into the walls. You may notice white marks on the walls as a result.

Resolve Your Rising Damp Problems Today

At Advanced Damp, we’ve been damp proofing homes and commercial properties for more than 3 decades. That’s why we understand that accurate damp proof course installation is the key to keeping rising damp at bay and avoiding unnecessary expenses later down the line.

For instance, we use only high-quality techniques like damp proof membranes and state-of-the-art tools to ensure that your home remains safe and comfortable for years to come. Plus, every damp proof course that we install is designed with durability in mind as part of our 20-year guarantee.

Call us today at 0300 3737 7251 for your free damp proof course quote and check out our full range of services to discover exactly how we can protect your property today.

The Bottom Line


Damp-proof courses (DPCs) are essential for building protection. A properly designed and maintained DPC protects the building and offers a healthy living environment by avoiding rising Dampness, regulating lateral Dampness, and reducing condensation.

Maintaining, repairing, or replacing a damp-proof course requires professional help. Professionals have the skills, experience, and instruments to handle complicated dampness concerns. Consulting a damp-proofing specialist ensures DPC integrity and building damage prevention.

We cannot stress the importance of a working DPC. Regular inspections, maintenance, and professional advice can safeguard your building from dampness and excess moisture-related issues!

Frequently asked questions

Picture of Jake Fitzgerald - Damp Surveyor

Jake Fitzgerald - Damp Surveyor

Surveyor of Timber & Dampness in Buildings (CSTDB) & ( MRICS ) Chartered Quantity Surveyor

Jake is a qualified chartered quantity surveyor and experienced damp specialist with a unique skill set in thermal imaging. With a focus on effective solutions, Jake combines his expertise in quantity surveying and thermal imaging to accurately assess and address damp-related issues. He utilises advanced technology to identify hidden moisture sources and develop targeted strategies, ensuring comprehensive and cost-effective solutions for his clients. With a commitment to open communication and client satisfaction, Jake delivers cutting-edge solutions that tackle damp challenges head-on.

Connect with him on Linkedin...

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Welcome to Advanced Damp, where we bring over 30 years of professional expertise in damp treatments to homes and businesses across the nation.

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