Drain Tile. Waterproofed walls should be blanketed
with coarse rock, underlain at foundation level with perforated
drain tile connected to adequate sumps or existing storm water
systems. Drain tile must be sloped to outlets. The top of the
drain tile should not be higher than 2 inches (51 millimeters)
below the bottom of the interior floor slab.
Slope of Concrete Slabs. All horizontal surfaces
should have slope of 1/4 to 1/2 inch per foot (2 to 4 percent) in
the monolithic pour if possible. Dead level slabs are often
Walls. Walls may require nailers to secure the top of
the membrane 6 to 8 inches (152 to 203 millimeters) above grade.
Horizontal nailers should be provided at 6-foot (1829-millimeter)
elevation intervals, set in a bed of bituminous material and
waterproofed with additional layers of fabric and bituminous
cement. Plies of felt or fabric should run vertically.
Expansion Joints. These joints must receive preformed
neoprene rubber gaskets, properly flashed.
Membrane Selection. The membrane may include use of
felts, fabric and/or proprietary-coated fabric set in hot or cold
bituminous material or proprietary adhesive. System should be
multiplied, with sufficient plies to withstand the anticipated
hydrostatic pressure. The following table offers guidelines for
determining the number of felt and/or fabric plies and moppings
needed to resist different hydrostatic pressures:
BITUMEN APPROX. TOTAL
If single-ply sheet-applied membranes, such as PVC,
neoprene, butyl, EDPM, Hypalon, etc., are elected, great care
must be taken in the provision and testing of the lap seams
before covering or back filling. All systems must be protected