Car park lining in Staffordshire

Ground that shouldn't take the water

Permeable paving is a natural fit for car parks, but much of Staffordshire is ground the drainage engineer won't let it soak into. On former mining and industrial land around Stoke-on-Trent and Cannock, infiltration could move contamination. In the Trent and Dove valleys, a shallow water table leaves little room between the sub-base and the groundwater. On the mudstone, the water simply wouldn't go.

Lining answers all three. The stone layer acts as a shallow reservoir, with the rain held on a welded sheet and metered out through a restricted outlet to whichever sewer or brook the drawings name.

Where we line

Staff and HGV parking at distribution sites along the A38, A50 and M6, retail and leisure car parks in the Potteries, parking courts on housing around Lichfield, Stafford and Burton, and public car parks at schools and health centres. Where the sub-base can't hold the full design volume, it often links to a crate tank, which we install as well.

In the Trent valley, where water sits close below the surface, the formation for a lined car park is often kept shallow, and the engineer may check the liner for uplift. Our concern is the bed itself: it has to be firm and dry enough to weld on, and we won't line over standing water.

The lining sequence

Digging, and shaping the falls, is down to your groundworker. If something's wrong with the bed, we say so before a sheet goes down.

• Formation checked for level, falls and sharp stone
• Fleece cushion laid wall to wall and lapped up the sides
• Membrane panels in LLDPE, HDPE or PP, heat-welded on site
• A test weld made and recorded
• Outlets, overflows and penetrations sealed into the sheet
• Upper geotextile placed to protect the liner

Scope and records

Our work ends at the upper fleece. Stone and surfacing are for your team, and the sooner they follow us the less chance a dumper finds the bare sheet. You keep the weld test records and handover documents for building control and the drainage file.

If kerbs, gullies or lighting bases pass through the liner, let us know early, so each one is sealed into the sheet rather than cut round afterwards.