What reglet height is typical?

Consultant drawings vary; common practice exceeds the expected water line and local code minimums. Petroseal submittals show upturn heights per project—do not copy a generic 150mm without checking the spec.

raft

Raft-to-Retaining-Wall Waterproofing Detail

Continuity at the horizontal–vertical junction: reglets, fillets, lap direction, and PetroGrip SBS sequencing on Pakistani basements.

Petroseal Technical TeamSeptember 202610 min read

Direct answer

The raft-to-retaining-wall junction is a three-dimensional lap problem. Horizontal PetroGrip SBS on the raft must turn up the wall; vertical wall membrane must overlap that upturn with full torch weld or self-adhesive transition per detail. A missing fillet, cold joint without waterstop, or wall membrane starting below the raft upturn creates the most common basement leak path on Pakistani sites.

Draw the detail before rebar congestion prevents access. Petroseal recommends coordinating with structural drawings for construction joint location so PVC waterstops align with the membrane plane.

Sequence checklist

Raft concrete cured; primer on horizontal field
Primary raft SBS with upturn to marked reglet height
Internal fillet (where detail requires) before wall sheet
Wall SBS overlapping raft upturn—minimum lap per method
Probe welds before protection board and backfill

Double-layer at the junction

When double-layer SBS is specified, stagger laps so no single vertical line aligns through both plies at the inside corner. Both plies remain SBS unless exposure schedule changes at grade. Domestic manufacturers including Petroseal and Roofline supply multiple thicknesses—detail consistency matters more than brand at this junction.