Case 2

Good Practices

Pipe Penetration

Design

Service penetrations are weak points and are vulnerable to leakage. They should be grouped, preplanned
and boxed out to minimise penetration through waterproofing. Install penetrations in cast-in-situ sleeves to allow independent movement of pipes and reduce coordination between different trades in accordance with BS 8102, SS 637 (formerly CP 82) or other relevant and equivalent standards. (SS 652: A.3.2.1)

Waterstop should be installed to protect the waterproofing system.

Waterproofing design details such as angle fillet provision, upturns and overlaps of membrane at the pipe penetration should be emphasized. A minimum of 150mm lap is important at the fold junction of pipe penetrations. Angle fillets must be used where sharp turns are encountered such as wall pipe junction. Size of fillets should be around 25mm x 25mm.

Construction

Ensure there are no congestions around pipes for easy pouring and vibration of concrete. Additional reinforcement is recommended to counteract the concentration of shrinkage stress, especially at corners
of openings, in accordance with BS 8102 and SS 637 (formerly CP 82) or other relevant and equivalent
standards. Conduits should be made in order not to allow water leaks in the basement. (SS 652: A.6.2)

The application of any membrane should begin at a corner diagonal to the entrance and upturns at wall floor junctions to avoid stepping on the applied area. Rollers or brushes can be used for the application
of the membrane in most locations. Rollers with the same width as the upturn could achieve an even and uniform application. However, critical locations where pipe penetrations and wall joints exist should be waterproofed using a brush to ensure good coverage.