Damp & Water Proofing

Damp & Water Proofing – Essential Protection for Walls, Floors & Foundations

MGN Builders Merchants offers a complete selection of damp proofing and waterproofing products tailored to tackle moisture intrusion in homes, extensions, basements, and new builds. From high-performance damp proof courses (DPCs) to reliable cavity drain membranes and versatile bitumen emulsions, this category includes everything you need to protect and prepare internal and external structures from rising damp, penetrating water, and condensation damage.

Whether you’re working on a retrofit or specifying a waterproofing layer for a new structure, our carefully selected range balances performance with ease of application. These products are commonly used beneath concrete slabs, behind retaining walls, on masonry, and in flooring systems where long-term water resistance is essential.

Installation: Reliable Solutions Made Simple

Damp proofing solutions in this category are designed to be effective while keeping installation practical for both professionals and experienced DIYers. Most damp proof membranes and DPC rolls are installed between brick courses or beneath concrete floors, forming a barrier that blocks rising moisture from reaching interior finishes or timber structures.

For cavity wall applications, cavity drain membranes offer an advanced solution. How do you install a cavity drain membrane? These membranes are typically fixed to internal walls using special fixing plugs, then covered with plasterboard or other finishes. Their dimpled surface creates a controlled cavity behind the wall lining, allowing moisture to move freely into a designated drainage point or sump system without penetrating into the living space.

Experts at mgnbm.co.uk recommend installing cavity drain membranes as part of a full waterproofing system in basements or below-ground extensions, where traditional tanking methods can fail due to hydrostatic pressure.

Not Just Barriers – What These Products Actually Do

Damp proofing is more than stopping water, it's about preserving building integrity, preventing health issues, and enabling high-quality finishes to last. When left unaddressed, damp can cause rot in timber, mould growth on walls, and long-term structural damage to masonry. Proper waterproofing stops these issues at the source.

Among the most versatile solutions are bitumen emulsions, liquid-applied coatings that form a flexible and water-resistant membrane on contact surfaces. What is bitumen emulsion? It’s a stable mixture of bitumen and water, enhanced with emulsifying agents to make it easy to apply to masonry, concrete, or timber. Once dried, it leaves behind a durable and seamless waterproof layer.

How bitumen emulsion is made involves dispersing bitumen in water using surfactants and high-shear mixing, creating a fluid that can be brushed, rolled, or sprayed on surfaces. This composition gives it excellent adhesion and flexibility, even in areas subject to minor movement or vibration.

Where to Use These Products for Maximum Impact

From residential to light commercial applications, the items in this range are suitable for:

• Cavity walls, to manage moisture movement behind internal finishes

• Concrete floors, to block rising damp from ground level

• External walls and retaining structures, where moisture may seep laterally

• Wet rooms, kitchens, and bathrooms where vapour control is critical

• Below-ground spaces including cellars and basements

mgnbm.co.uk recommends using DPC rolls and bitumen emulsions in combination to create multi-layered protection where conditions are especially humid or wet. For example, pairing a membrane with a liquid-applied coating improves reliability around joints and corners.

Range Highlights and Specialist Options

We stock a wide variety of damp proof courses in multiple widths and thicknesses, from basic polyethylene DPCs to robust high-load versions ideal for cavity walls. Our cavity drain membranes come in roll or sheet formats with compatible accessories such as sealing tapes and plugs for ease of use. Bitumen emulsions are offered in 5L and 25L containers depending on the scale of your project.

To improve airtightness and performance, our selection also includes high-grip jointing tapes, primer coatings, and drainage outlets. This gives you a complete toolbox for both basic and complex damp proofing applications.

Experts at mgnbm.co.uk advise selecting the right membrane and emulsion combination based on the substrate type, expected water load, and installation environment, especially in older buildings where moisture patterns may be unpredictable.