400 micron yellow polythene membrane providing a long-term barrier against radon gas, CO2, methane and ground moisture beneath solid concrete ground floors. Supplied in 4m wide rolls.
Size
Price
QTY
4m x 20m
£94.90£113.88
4m x 12.5m
£79.90£95.88
This yellow radon gas barrier roll is a 400 micron polythene sheet membrane designed to protect buildings from radon gas and ground moisture beneath solid concrete floor slabs. Radon is a naturally occurring radioactive gas that seeps up from certain ground conditions, particularly in areas of granite bedrock, and prolonged exposure indoors is a recognised health risk. Installing a proper barrier before the slab is poured is the most effective way to deal with it, and this is exactly what this membrane is built for.
The 400mu gauge gives you a meaningful thickness that holds up during the concreting process. Thinner membranes can be a frustration on site — workers walking across them, rebar being placed, concrete being poured. At 400 microns you get a material that can take a reasonable amount of site handling without turning into a patchwork of tape repairs before the pour has even started. Yellow colouring also makes it easy to identify on site and confirm continuity of coverage at a glance.
What the Yellow Radon Gas Barrier Roll Protects Against
Beyond radon, this membrane also acts as a barrier against CO2, low-level methane and ground moisture. That makes it particularly relevant on brownfield sites or in areas with a history of coal mining, landfill, or similar ground gas risk. It does a combined job: ground gas exclusion and damp proofing in a single installed layer. That is a sensible arrangement when you are pouring a slab anyway, since laying a separate DPM afterwards is not an option.
Sizing and Coverage
Available in two roll sizes, 4m x 12.5m and 4m x 20m, giving coverage of 50 or 80 square metres respectively. The 4m width suits most domestic ground floor pours without requiring excessive overlapping, though laps should always be taped and sealed correctly at joints. Supplied in yellow for easy site identification, this barrier is intended to be installed within the concrete slab construction for the lifetime of the building.
Suitable for new build ground floor construction where the ground risk assessment or local building regulations indicate a radon or ground gas precaution is required.
Pro Tip: Always tape and seal all laps with a compatible gas-resistant jointing tape, not standard polythene tape, any unsealed joint is essentially a gap in your radon protection and will fail an air test.
This yellow radon gas barrier roll is used in new build ground floor construction wherever a ground gas or radon precaution is required. It sits within the floor build-up, installed beneath or within the concrete slab, providing a continuous sealed membrane across the full footprint of the building. Common applications include housing on granitic soils, sites near former coal workings, brownfield developments and any project where a site-specific risk assessment has identified elevated radon or ground gas levels.
Groundworkers, builders and flooring contractors on residential and commercial new builds will use this type of membrane as a standard part of the floor specification in affected areas. It is also appropriate where building control or a structural engineer has stipulated a gas-resistant DPM as a precautionary measure.
Best For
Radon gas protection in new build ground floors
Low-level methane and CO2 exclusion
Ground moisture and damp proofing
Brownfield and former mining sites
Areas with elevated radon risk assessments
Compatible With
Solid concrete ground floor slabs
Gas-resistant jointing tape at laps
Standard concrete pour processes
Residential and commercial new build construction
Key Specifications
Gauge: 400 microns (400mu)
Colour: Yellow
Width: 4 metres
Available sizes: 4m x 12.5m (50m²) or 4m x 20m (80m²)
Material: Polythene sheet membrane
Lifetime performance within installed slab
Not suitable for: Not suitable for use as a retrofit barrier in existing floor voids or suspended floors where access is restricted. This product is intended for installation within new concrete slab construction and is not a repair solution for existing floors.
The barrier should be laid across the prepared sub-base before concreting begins, with the membrane running continuously across the full floor area. All laps must overlap by a minimum of 300mm and be sealed using a gas-resistant jointing tape. Take care around penetrations such as pipes and service ducts, since these require specific sealing details to maintain the integrity of the barrier.
Once the membrane is in position and all joints and penetrations are sealed, the concrete slab is poured over the top in the usual way. The yellow colour helps confirm full coverage before the pour begins. Avoid dragging sharp objects such as rebar directly across the membrane surface during fixing, and inspect for any damage or punctures before the pour starts.
Clear and compact the sub-base, removing any sharp stones or debris that could puncture the membrane
Unroll the yellow radon gas barrier across the full floor area, working from one end to the other
Overlap all joints by a minimum of 300mm and seal immediately using a compatible gas-resistant jointing tape
Seal all edges carefully where the membrane meets walls or upstands, turning the membrane up and taping to the wall face
Cut neatly around pipe penetrations and service entries, then seal using purpose-made pipe boots or gas-resistant tape to maintain continuity
Inspect the entire membrane surface before concreting for any punctures, tears or unsealed laps
Pour the concrete slab over the sealed membrane in the normal way, taking care not to drag sharp fixings or formwork across the membrane surface
Does this membrane need to go above or below the insulation in a ground floor build-up?
It depends on the floor specification and the type of insulation used. In most domestic builds the radon barrier sits directly on the sub-base below the insulation, with the concrete slab above. However some specifications place it above the insulation as part of a combined DPM arrangement. Check your architect or structural engineer's floor build-up drawing, as the position affects how joints and upstands are detailed.
What size roll should I order for a standard house footprint?
The 4m x 20m roll covers 80 square metres, which suits a typical semi-detached or detached house ground floor in a single roll or with minimal joining. For smaller extensions or single rooms the 4m x 12.5m roll at 50 square metres is usually sufficient. Factor in your laps and upstand allowances when calculating coverage, and it is always worth having a small amount of additional material on site.
Manufactured from polythene sheeting at a 400 micron gauge, this membrane provides resistance to radon gas, CO2, low-level methane and ground moisture. The yellow pigmentation aids site identification and confirms installation continuity. At 400mu the material offers a practical balance between puncture resistance during construction and workability on site. Intended for permanent installation within a concrete slab, the membrane is designed to maintain its barrier properties for the lifetime of the floor construction.
Reviews
There are no reviews yet.