Brownfield materials matched to contamination class.
Ground gas membranes, geotextile, structural waterproofing, contaminated fill, and remediation materials matched to your site's BS8485 characteristic situation (CS1–CS6). BBA certificate references included — your verification test passes first time.
B1 through B6 — full brownfield coverage
Ground Gas Membranes
BS8485 compliant gas membranes for CS1–CS6 sites. Wrong grade for contamination class = verification test failure.
Radon Sumps & Vent Systems
Sub-floor ventilation, radon sumps, pipe penetration seals. Complete gas protection system.
Geotextile & Separation Layers
Chemical-resistant geotextile, drainage cell, separation layers for contaminated ground.
Structural Waterproofing
Type A, B, C waterproofing per BS8102. Basement conversions and below-ground structures.
Contaminated Fill Classification
Certified clean fill suppliers, Environment Agency waste classification compliance.
Remediation Materials
Lime stabilisation binders, soil treatment, contamination capping materials.
Most CS2 sites use the wrong membrane grade
The classification problem
BS8485:2015+A1:2019 classifies brownfield sites from CS1 (lowest risk) to CS6 (highest). Most UK brownfield sites are CS2 — Amber 1 under NHBC. The required membrane grade and sub-floor ventilation differ significantly between CS1, CS2, and CS3 — and developers consistently buy CS1-grade products for CS2 sites.
The cost of getting it wrong
Wrong membrane grade means verification test failure under CIRIA C735. Failed verification means NHBC LQ03 condition not discharged — your warranty is refused. Units cannot be sold. We match your contamination classification to the correct certified system before procurement.