BBA approved 1000 gauge polythene DPM at 250 microns thick. Suitable for use as a damp proof membrane under concrete slabs and screeds, or as temporary protection sheeting on site. A straightforward, proven solution for moisture control.
A 1000 gauge polythene DPM is the standard choice for most ground floor applications where you need to stop moisture rising from the sub-base into the floor construction above. At 250 microns thick, this membrane sits at the heavier end of general-purpose DPM sheeting, giving it the durability to survive the rough end of a construction site without picking up punctures during pour and screed work. BBA approval means it has been independently assessed and meets the requirements for use as a damp proof membrane in new-build and renovation projects across the UK.
Damp proof membranes are one of those products that do their job invisibly for decades — or cause expensive problems if the wrong one gets used. The 1000 gauge specification is widely specified by structural engineers and building control for domestic ground floors, and it is the figure you will see referenced in most building regulation guidance for DPM installations beneath concrete slabs and floating screeds.
Where 1000 Gauge Polythene DPM Gets Used
On a typical new-build or ground floor renovation, this goes down over the hardcore and blinding layer before the concrete slab is poured. It creates a continuous barrier between the ground and the floor build-up, stopping moisture from working its way up through the slab and damaging floor finishes, timber, or insulation. It is also used as temporary protection sheeting to cover materials, freshly laid concrete, or finished surfaces on site during construction.
Temporary Protection Applications
As a protection sheet, polythene at this gauge is tough enough to take foot traffic and resist tearing when draped over materials or laid across finished floors during subsequent trades. It is the kind of thing that gets used in a dozen different ways on any active site, which is probably why most builders keep a roll of it on the van.
The BBA certification gives this 1000 gauge polythene DPM the independent backing required for projects where building control sign-off depends on specified materials being used correctly and documented. For groundworkers, builders and self-builders who need to tick that box, it matters.
Pro Tip: Always lap DPM sheets by at least 150mm at joints and tape them with a compatible jointing tape to maintain a continuous vapour barrier, because an unjointed edge effectively means no DPM at all.
This polythene DPM is used primarily as a ground-bearing floor membrane, laid under concrete slabs and sand and cement screeds to prevent moisture transmission from the ground into the floor construction. It is a standard material for groundworkers, builders and main contractors working on domestic extensions, new builds and ground floor refurbishments. Secondary use as temporary protection sheeting is common across all trades on active construction sites, covering materials, finished surfaces, and plant during poor weather or between trades.
Best For
Ground-bearing concrete floor slabs
Sand and cement screeds
Floating floor build-ups
Temporary site protection sheeting
New-build ground floor construction
Ground floor renovation and refurbishment
Key Properties
1000 gauge thickness
250 microns
BBA approved
Moisture and vapour barrier
Puncture resistant for site use
Suitable for use beneath concrete
Works With
Concrete slabs
Sand and cement screed
Rigid insulation boards
DPM jointing tape
Hardcore and blinding layers
Not suitable for: Not suitable for use as a structural waterproofing membrane in tanking applications or below water table conditions. Not a replacement for specialist radon barrier membranes where radon protection is required.
Prepare the sub-base by laying and compacting hardcore, then blinding with sharp sand to create a smooth surface free from sharp edges or protruding stones that could puncture the membrane. Roll the DPM out over the blinding layer, ensuring it laps up the internal face of the perimeter walls by a minimum of 150mm to tie in with the vertical DPC.
Where sheets need to be joined, lap by at least 150mm and seal with a compatible DPM jointing tape. Keep the membrane as flat as possible before the concrete is poured to avoid creating voids. For temporary protection use, simply unroll and position over the area to be protected, weighting the edges to prevent wind lift on exposed sites.
Compact and blind the hardcore sub-base to remove sharp edges and stones
Unroll the DPM over the blinding layer, working from one side of the slab area to the other
Lap the membrane up the internal faces of all perimeter walls by a minimum of 150mm
Where sheets must be joined, overlap by at least 150mm and seal with a compatible jointing tape
Check the membrane for punctures before pouring and patch any damage with an off-cut taped in place
Pour and screed the concrete carefully to avoid displacing or tearing the membrane during the pour
Is this DPM suitable for use under underfloor heating screeds?
Yes. A 1000 gauge polythene DPM is suitable for use beneath both sand and cement screeds and liquid screeds used with underfloor heating systems, provided the screed mix and depth specified by the UFH supplier are followed. The membrane provides the moisture barrier required beneath the screed regardless of what is embedded in it above.
What does BBA approved mean for a DPM, and does it matter for building control?
BBA stands for British Board of Agrément, an independent certification body that tests building products against defined performance standards. For a DPM, BBA approval confirms the product has been assessed as fit for purpose in its stated application. Many building control inspectors and engineers will ask for evidence of product suitability, and BBA approval is widely accepted as meeting that requirement on domestic and commercial projects.
This damp proof membrane is manufactured from virgin or recycled low-density polythene (LDPE) to a thickness of 250 microns, equivalent to 1000 gauge. At this thickness the sheet provides effective resistance to moisture vapour transmission from the ground while remaining flexible enough to handle and lay on site. BBA certification confirms it meets the requirements of BS 8102 and related guidance for use as a ground floor DPM in UK construction.
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