Black Damp Proof Membrane

Features & Benefits

• Black Damp Proof Membrane provides a durable, impermeable barrier for building, landscaping and general protection applications.
• Each complete roll opens to 4m x 25m (13.12ft x 82.02ft).
• The membrane is multifolded down to approximately 1m (3.28ft) wide for easier storage, handling and unrolling.
• The 1000-gauge polythene measures approximately 250 microns or 0.25mm thick.
• One roll provides a gross coverage area of 100m² (approximately 1,076.39 sq ft).
• The black polythene blocks light and prevents water from passing through the material.
• Some customers use the membrane as weed control where they want to prevent all plant growth.
• Unlike permeable weed-control fabric, this membrane will not allow wanted plants, grass or other vegetation to grow underneath it.
• The flexible material can cover large areas while also allowing installers to cut it around corners and obstacles.
• The black finish makes the membrane suitable for concealed groundworks and numerous outdoor applications.
• We sell this product per complete roll.
• Delivery is available throughout mainland UK.

Common Uses

• Creating a damp barrier beneath suitable ground-supported concrete floors
• General construction and groundworks
• Covering floors or materials during building work
• Temporary weather protection
• Lining and separating materials
• Suppressing weeds and all other vegetation in areas where no plant growth is wanted
• Covering unused ground before adding gravel or other suitable surface materials
• General landscaping and outdoor protection
• Wrapping or covering bulky items

Black Damp Proof Membrane 4m x 25m

Our Black Damp Proof Membrane is a heavy-duty black polythene sheet supplied in a complete 4m x 25m roll. It provides an impermeable barrier that suits a range of construction, landscaping and general protection applications.

The sheet opens to its full 4m width when unfolded. However, the manufacturer multifolds it down to approximately 1m wide on the roll. Consequently, the roll is easier to store, transport, handle and position before installation. The folds do not reduce the membrane’s full open width or overall coverage.

At 1000 gauge, the membrane measures approximately 250 microns or 0.25mm thick. Therefore, it offers greater strength and puncture resistance than lightweight polythene sheeting while remaining flexible enough to unfold, position and trim on site.

Black Damp Proof Membrane Specifications

How the Black Damp Proof Membrane Is Folded

Although the membrane opens to 4m (13.12ft) wide, it comes multifolded to approximately 1m (3.28ft) wide. This compact format makes the product easier to carry and position than a full-width 4m roll.

First, place the roll near the installation area. Next, unroll the required length while the material remains folded. Then, carefully unfold the layers until the membrane reaches its full 4m width. Finally, smooth the sheet into position without dragging it across sharp surfaces.

The multifolding only changes the packed width. It does not change the open dimensions, material thickness or gross coverage.

Using Black Damp Proof Membrane for Weed Control

Some customers use Black Damp Proof Membrane as a weed-suppression sheet because the black, impermeable material blocks light and prevents growth beneath the covered area. However, it suppresses all vegetation rather than selectively controlling weeds.

Therefore, the membrane will also prevent grass, flowers, crops and other wanted plants from growing underneath it. Only install it in places where you do not want any vegetation to survive or develop.

This product differs from woven or non-woven weed-control fabric. Permeable landscaping fabrics allow water and air to reach the soil, whereas this polythene membrane creates a non-permeable barrier. As a result, water cannot drain through the sheet and air circulation to the covered soil becomes restricted.

Do not place the membrane over plant roots or areas where trees, shrubs, flowers or grass need access to water and air. Instead, reserve it for locations where complete vegetation suppression is the intended result.

Drainage When Using Black Damp Proof Membrane Outdoors

Because the material does not allow water to pass through, rainwater may collect on top of the membrane or run towards surrounding areas. Accordingly, plan the fall and drainage of the installation before covering the sheet with gravel or another surface material.

Avoid forming low points where standing water could accumulate. Additionally, make sure runoff will not flow towards buildings, neighbouring land or areas vulnerable to flooding.

Weeds should not grow through intact membrane. Nevertheless, airborne seeds may establish in soil, dust or organic debris that collects on top. Punctures, uncovered joints and gaps around the edges may also allow new growth. Careful installation and routine surface maintenance will help reduce these problems.

Selecting a Damp Proof Membrane

A damp proof membrane helps resist moisture travelling from the ground into a floor construction. However, the correct material thickness and installation method depend on the building design, substrate and applicable project requirements.

This product is 1000 gauge, which equals approximately 250 microns. Some construction details specify a 300-micron or 1200-gauge polyethylene membrane. Therefore, check the project specification and confirm the requirements with the designer, contractor or building-control professional before ordering.

Do not assume that one membrane specification suits every building project.

Installing Black Damp Proof Membrane Beneath Floors

When the project specification permits a 1000-gauge membrane, the sheet can form part of a suitable ground-floor construction. The wide 4m format helps reduce the number of joints across many installation areas.

Carefully position the membrane over the prepared base and allow enough material for overlaps, junctions, upstands and trimming. Next, seal the joints with a compatible tape or jointing system that suits the application.

The membrane should form a continuous barrier. Therefore, pay close attention to edges, corners, service penetrations and connections with other damp-proofing components.

Preparing the Base

Before laying the Black Damp Proof Membrane, remove sharp stones, exposed fixings, broken materials and other objects that could puncture the sheet. Level the surface where necessary and make sure it offers continuous support.

Avoid dragging the membrane across rough ground. Instead, carry and position the roll carefully before unfolding it. Where the substrate presents a higher puncture risk, consider adding a suitable protective layer as required by the project design.

Good preparation reduces damage and helps the membrane remain continuous throughout installation.

Overlaps, Joints and Edges

Allow sufficient material at every joint so the sheets can overlap in accordance with the project specification. Then, clean and dry the joining area before applying a suitable sealing tape or approved jointing method.

Press the joint firmly and check it along its full length. Furthermore, prevent wrinkles, trapped debris and tension from affecting the seal.

At edges and wall junctions, connect the membrane to compatible damp-proofing components where the design requires it. A continuous installation helps prevent moisture from bypassing the barrier.

Service Penetrations

Pipes, ducts and other service penetrations require careful detailing. Cut the smallest practical opening and seal the membrane around the service with a compatible system.

Large, rough or poorly sealed openings can weaken the installation. Therefore, inspect each penetration before later construction work covers the membrane.

Protecting the Black Damp Proof Membrane

After installation, protect the membrane from heavy foot traffic, dropped tools and sharp materials. Do not use the sheet as an unprotected working surface.

If contractors need to cross the area, provide suitable temporary protection. Additionally, inspect the membrane before placing insulation, reinforcement or concrete above it. Repair any punctures, cuts or damaged joints with a compatible method before continuing.

Calculating the Number of Rolls Required

Each roll provides a gross area of 100m² (approximately 1,076.39 sq ft). However, the usable coverage will be lower after allowing for overlaps, upstands, junctions, penetrations and trimming.

To estimate the required quantity, calculate the total area and then add an allowance for installation waste and detailing. Complex layouts, numerous penetrations and irregular room shapes will generally require a larger allowance.

For example, a simple rectangular area may use less additional material than a floor with several corners, columns and service entries.

Other Uses for Black Damp Proof Membrane

The strong black polythene also suits many general-purpose applications. Customers may use it to cover building materials, separate different surfaces, line suitable areas or protect large items from dust and moisture.

However, the material creates an impermeable barrier. Therefore, always consider condensation, trapped moisture and ventilation before wrapping or covering moisture-sensitive items.

For long-term or safety-critical applications, confirm that the product meets the specific technical requirements of the project.

Ground Gas Limitations

This product is sold as a general damp proof membrane and heavy-duty polythene sheet. We do not describe it as a certified radon, methane or ground-gas membrane.

Where a site assessment identifies radon, methane, carbon dioxide or another ground-gas risk, use a purpose-designed and appropriately certified membrane system. In addition, follow the project designer’s installation and ventilation requirements.

Cutting and Handling Black Damp Proof Membrane

Use suitable cutting equipment and work on a stable surface. Keep the sheet away from sharp edges while measuring and trimming.

Because the material opens to 4m wide, two people may find it easier to unfold and position in windy conditions or confined areas. Furthermore, place unused material back into secure packaging to keep it clean and reduce accidental damage.

Repairing Damage

Inspect the sheet for punctures, cuts and tears before covering it. If damage occurs, clean and dry the affected area before applying a compatible repair material.

The repair should extend beyond the damaged section and create a secure seal around it. For construction applications, follow the project specification and obtain professional advice where necessary.

Storage

Store the roll in a clean, dry place away from sharp objects, excessive heat and direct sunlight. Keep it on a stable surface and protect the edges from impact.

Additionally, retain the original packaging until you need the membrane. Clean material is easier to join, seal and inspect during installation.

Also Known As

This product may also be described as:

• DPM
• Damp proof membrane
• Black polythene membrane
• 1000-gauge DPM
• 250-micron polythene sheet
• Heavy-duty black polythene
• Black plastic sheeting
• Impermeable weed-suppression sheet
• Ground-cover membrane

Food Safety

We have not confirmed this product as food-contact approved. Therefore, do not place it in direct contact with food unless you have completed the necessary suitability checks for the intended application.

PPWR

The EU Packaging and Packaging Waste Regulation (PPWR) introduces requirements that affect packaging placed on the EU market. If you intend to use this product as packaging for goods supplied into the EU, assess the complete packaging format and confirm its suitability for your application.

See the European Commission’s packaging waste information for further guidance.

Sample Requests

A small material sample may be available where stock and cutting arrangements permit. Samples help you assess the colour, thickness and flexibility, but they do not demonstrate the full 4m open width or complete roll format.

To request a sample, email sales@expresspackaging.co.uk or call 0121 622 2347.

Illustration Only

Product photographs are for illustration only. Colour, finish, folding, roll dimensions, core size, packaging and appearance may vary slightly between manufacturing batches. Please use the written specifications when checking suitability.