Car park lining in the West Midlands

Ground that rules out infiltration

Mercia Mudstone underlies much of Warwickshire, Worcestershire and eastern Birmingham, and it barely drains. The Black Country and the Cannock coalfield add Coal Measures clays and made ground, some of it contaminated, where letting water percolate would move pollution downwards. Even on the sandstone, engineers can choose to keep paved-area runoff away from foundations.

For all of these, a lined permeable pavement keeps the surface-level benefits of SuDS while storing the water in a sealed layer, much like a shallow tank spread under the bays.

Source control under the 2025 standards

England's 2025 national SuDS standards, read alongside the NPPF, favour dealing with rain close to where it lands. A permeable car park does exactly that, and a liner lets the same idea work on ground that can't absorb the water.

• Supermarkets and retail parks on the edges of the region's towns
• Staff and visitor parking at distribution sites along the M6, M42 and M54
• School, college and health-building car parks
• Park and ride sites and station parking

What our crew does on the formation

The groundworks team digs out and shapes the base to the engineer's levels. We then check it is firm, clear of anything sharp and falling towards the outlets before laying anything. Fleece goes down first, then the impermeable sheet, joined by hot-wedge welding along every seam, with that day's trial weld tested and entered in the log.

Outlets and overflows are sealed through the membrane, edges are dressed up to level, and an upper fleece protects the liner from the stone that follows. The aggregate and the paving blocks are then laid by others.

Large retail and logistics car parks are usually lined in bays, so the stone can follow us across the site rather than waiting for the whole area to be finished. Each bay's welds go on the same record, so the finished car park has one continuous log however many visits it took.

Adding crate storage

Where the design volume exceeds what the aggregate can hold, crates are often built in below the bays. We install crate tanks across the region as well, including a 500m³ tank in welded HDPE at Bournville, so the lining and the tank can be one install with a single set of records.