Page 236 - Masonry and Concrete

Footings, Foundation Walls, Basements, and Slabs
235
FOOTINGS, FOUNDATION WALLS, BASEMENTS, AND SLABS

Concrete walls may be dampproofed with any of the dampproofing or
waterproofing materials listed above. Waterproofing membranes must
be protected from punctures and tears during the backfilling process.
Some materials such as polyethylene sheets are particularly vulnera-
ble to damage. Special protection boards can be erected over the mem-
brane, or insulating drainage mats can be used for this purpose.
For wet soils with a high water table or a water table which may
fluctuate seasonally or under severe weather conditions, and for deep
foundations in multistory below-grade structures, Figure 6-41 illus-
trates appropriate drainage and waterproofing techniques. Slabs can be
waterproofed in different ways, depending on the type of membrane
being used. Horizontal membranes for below-grade slabs are often cast
on a thin “mud slab” and the structural slab is then cast on top, or the
membrane is installed on the structural slab and a topping slab added
as a wearing surface. This provides a stable subbase to support the

BITUMINOUS
WATERPROOFING
MEMBRANE SEALANT

DRAINAGE MAT
STRUCTURAL SLAB

WATERPROOFING
GRANULAR FILL MEMBRANE
WRAPPED IN
FILTER FABRIC

MUD
SLAB
DRAIN DRAINAGE BED
AND CAPILLARY
BREAK

OPTIONAL WATERSTOPS
FIGURE 6-41
Waterproofing. (from Beall, Christine, Thermal and Moisture Protection Manual, McGraw-Hill, New York).

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