Direct answer
Raft waterproofing fails at pile heads when generic field patches do not bond to steel or concrete cut-offs, or when raft membrane stops short of the collar. Sequence: approved pile cap finish, compatible grout or fillet, primer, PetroSelfGrip or SBS reinforced patch, then field raft sheet welded to the collar with lap inspection.
Any Lahore contractor installing PetroGrip or other membranes must detail pile heads on the shop drawing—Unicorn, Roof Power, and manufacturer-direct installs share the same engineering requirement.
Detail checklist
- Pile cut-off level per structural drawing
- Surface prep and corrosion treatment where applicable
- Collar height above raft membrane line
- Self-adhesive transition where torch is restricted near cut-off
- Probe lap before concrete screed or protection