Gas membrane installation in Birmingham

Where the risk comes from

The city's regeneration areas are old industrial land: Digbeth and Eastside, the Jewellery Quarter, the canal corridors, Tyseley and the Tame valley around Aston and Nechells. Gasworks, foundries, metal finishers and filled-in canal arms leave made ground that can give off ground gas or hold hydrocarbons and solvents.

The gas risk assessment, under BS 8485, sets a protection level for each building. It may call for a gas-resistant membrane on its own, or a membrane as one part of a wider scheme the designer has set out. We install whatever the specification names.

Piled buildings and dense details

Taller buildings on city plots are usually piled, and every pile, pile cap and ground beam is a route for gas past a badly finished membrane. We collar and seal each penetration individually, along with drainage pipes, ducts and service entries, and treat lift pits and level changes as details in their own right.

On a Digbeth or Jewellery Quarter slab, each joint between sheets is welded or sealed to the specification, in the way the maker prescribes for that sheet. If rain or a cold snap would stop a joint forming properly, that bay waits.

• A smooth, clean substrate of blinding or slab
• Pile caps and service positions fixed before we lay
• A plan to protect the membrane once it's down

Proving the barrier works

Gas protection is buried under concrete within days, so the record matters. On higher-risk Birmingham plots the warranty provider or the council will often want a validator to see the membrane before the pour, and integrity testing can be arranged alongside that. Whether or not a validator attends, the warranty file gets our installation records.

City-centre logistics

Inner-city slabs come with loading bays, booked deliveries and a frame contractor waiting to pour. Membrane rolls are small enough to carry by hand to a basement or podium, and we lay in step with the pour plan so each area is finished, sealed and inspected before the steel fixers move in.

Once down, the sheet is vulnerable to boots, barrows and dropped bar. We agree with the site team how it will be protected until the concrete covers it.

Gas protection and drainage from one installer

Brownfield plots in Birmingham often need a lined attenuation tank as well as gas protection. We install both, so the same firm stands behind the membrane under the building and the welded tank under the yard.