Ardex SRO 834 Waterproofing Specification - Retaining Walls
Single Layer, Bituminous Sheet Membrane - Protected System
Single layer, bituminous membrane system applied in sheets to approved substrates to form a fully bonded, protected continuous barrier on retaining walls against water penetration.
This single layer membrane system is suitable for situations where the likelihood of water penetration is low such as:
On the positive side of retaining walls with foundations above the permanent water table
Below grade basement walls above the permanent water table level.
Suitable substrates for this membrane include:
Masonry (concrete block) walls
Brick walls with render smoothing coat.
Substrates to which the bituminous sheet membrane are to be applied must be structurally sound and free of all contaminants (e.g. laitance). The substrates must have completed the recommended minimum curing/drying periods (e.g. 28 days for concrete) with all holes/voids filled with cement based patching mortars (e.g. ARDEX BR120FC / ARDEX BR340 system) and all surface protrusions ground flat. All internal corners are to be shaped with a cement based coving fillet (minimum 50 x 50mm).
ARDEX WPM188 Bituminous sheet membrane
Prime all prepared substrates with ARDEX WPM240 Bituminous primer and let dry.
Membrane Installation - torch on membrane
Apply the sheet membrane to the prepared substrates using LPG or LNG torch techniques with sheet overlaps (75mm side-laps and 100mm end-laps) fully welded together
Begin application from the lowest points of the structure and work upwards to the highest points.
Once the bituminous sheet membrane has been applied, the top (free) edge terminations shall be secured by one of the following systems
ARDEX Pressure Seal mechanically fixed into position
Liquid applied flashing such as the ARDEX WPM179 Bituminous latex.
Protection The bituminous sheet membrane is to be protected from sunlight and mechanical damage by covering with suitable protective materials such as;
ARDEX Protection Board prior to backfilling
5mm Geotextile fabric prior to backfilling
Double layer plastic (250 - 300 micron thickness each layer with the top layer laid at right angles to the bottom layer) slip sheet prior to placement of a self-supporting screed at a minimum 40mm thickness