The Complete Guide to Damp-Proof Courses

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Written by Warren Muschialli

Protecting a property from moisture damage and water ingress is crucial, but it doesn’t have to be complicated. There are widespread and simple steps that can be taken, such as installing a high quality damp proof course (DPC), that can help to safeguard a property against damp and the associated issues for the foreseeable future.

In this guide, we will cover everything you need to know about DPCs, including what they are, the different types of damp proof courses, the materials used, and how to choose the right one for your needs.

What is a Damp Proof Course?

A damp proof course acts as a barrier that prevents rising damp from permeating up through porous walls from the ground. It is typically installed between courses of brick and blockwork approximately 150mm above ground and is commonly used in modern construction to combat rising damp.

By preventing rising damp, a DPC serves as a protective barrier that restricts the infiltration of moisture upwards through the walls, preventing damage to internal wall coverings and finishes.

Unwanted moisture in properties can cause numerous problems, from deteriorating plaster and damaged decor, to black spot mould and even wet or dry rot in timber. And while most properties today come equipped with a DPC, it is still possible for these materials to fail over time or be bridged by high external ground levels such as pavement or driveway works. It’s therefore important to check that the DPC has not been bridged if you are experiencing internal damp issues.

What Causes Damp Walls?

Damp issues on internal walls aren’t only caused by water rising from the ground; they can also result from issues such as damaged roof coverings or malfunctioning rainwater gutters and downpipes. Other causes of dampness include defective external render or masonry, condensation problems, inadequate window and door sealing, plumbing leaks, defective drains in older buildings, and external flood events. In all such instances, a DPC would not be an effective form of protection against damp, so it’s important to correctly diagnose the cause of the problem before beginning to implement potentially costly remedial measures.

Types of Damp Proof Course (DPC)

The common types of damp proof courses include physical damp proof courses and chemical damp proof courses.

Physical damp courses are installed during the construction of the structural walls. Typically made from hard-wearing and durable polymers, and in a variety of widths depending on the depth of wall and whether a horizontal, vertical, or stepped damp proof course is required. The physical DPC is installed between courses of brick or blockwork approximately 150mm above ground level.

Chemical damp proofing, also known as an injectable damp proof course, involves injecting chemical agents or treatments at regular intervals into the mortar bed between courses of brick/blockwork, with the aim that the chemical will disperse within the porous material and create a new barrier to rising damp. Chemical DPCs are most commonly recommended and installed in older properties where a physical DPC was never initially installed, or in properties where the original physical DPC has since failed.

Damp Proofing Products from Newton Waterproofing

At Newton Waterproofing, we offer a wide range of damp proofing products, including:

• Sealing Mastic: Newtonite 801 Mastic
• 1200 Guage Damp Proof Membrane: DampSafe 802-DPM
• Non-Meshed Damp Proofing Membrane: Newton Newtonite
• 3mm Meshed Damp Proofing Membrane: Newtonite Lath Mesh Membrane and Newtonite, Non-Meshed Membrane
• Anti-Mould and Anti-Condensation Paint: Diasen C.W.C. Stop Condense
• Water Repellent Treatment For Exposed Walls: Diasen BKK
• High Performance Physical Damp Proof Course: DampSafe 809-HP DPC
• Ancillary Damp Proofing Products
• Damp Tolerable Epoxy DPM: Epoxy DPM

BBA Approved Damp Proof Membranes

Newton supplies a range of BBA approved damp proof membranes, coatings and ancillaries which are quick and clean to install and offer a permanent solution for damp proofing above-ground walls. In instances where internal damp is an issue but remedial DPC solutions are not feasible, or too invasive, then internal damp proof membranes can be a quick and unobtrusive solution to protecting your internal environment from structural damp.

Meshed and Non-Meshed Membranes for all Your Damp Proofing Needs

Newton supplies a selection of damp proofing membranes for above ground applications. These membranes isolate the new internal surfaces from any dampness within the wall, ensuring that it will never be affected by moisture or salts.

For example, Newtonite membrane is used where the internal wall is to be created using timber battens, a dry-lining frame or a block wall. On the other hand, the Newtonite Lath meshed membranes provide a mechanical key for plasters, renders, and dot and dab plasterboard.

Sealants and Ancillary Products

When installing damp proofing solutions, specialist ancillary products are critically important for achieving a correct installation. Newton’s comprehensive range of ancillary products includes all of the essential items such as fixing plugs, sealing tapes, and liners for joists, back-boxes and pipes.

Another example is Newtonite 801 Mastic, a multi-purpose product that seals penetrations through the Newtonite membranes, preventing a bridge between the damp substrate and the internal surface.

Preventing Mould & Water Penetration

Diasen C.W.C. Stop Condense is a white thermal coating for cold and poorly insulated surfaces. By warming the surface of the treated wall it prevents the formation of internal condensation and therefore also prevents the occurrence of mould.

Diasen BKK is a transparent and colourless wall coating that protects exposed external walls against driving rain and associated moisture penetration. The resultant dry wall is highly resistant to weathering and UV.

How Can Newton Waterproofing Help You?

We are dedicated to providing high-quality waterproofing services and technical support throughout the UK, and our team of experienced professionals and specialist contractors have the expertise to tackle even the most challenging projects. We adhere to industry standards and use proven methods, ensuring long-lasting results and peace of mind, so contact us today to get started.