Projex Shockmat was chosen because a high-strength, robust yet flexible protection medium was needed (one which could withstand the bar reinforcing being dragged over it & the placement of the reinforcing cages directly onto it). Shockmat fulfilled these criteria.
The Shockmat was laid over the membrane below the floor slabs and against the membrane on the outside walls of the basement prior to backfilling.
5mm thick Projex Shockmat was the preferred protection medium for the completed membrane works.