Page 232 - Masonry and Concrete

Footings, Foundation Walls, Basements, and Slabs
231
FOOTINGS, FOUNDATION WALLS, BASEMENTS, AND SLABS

3 /8" OR 1 /2" PARGE COAT
OF PORTLAND CEMENT MORTAR

DAMPPROOFING
DAMPPROOFING

DRAIN

GRANULAR FILL WRAPPED
IN FILTER FABRIC
FIGURE 6-38

Dampproofing. (from Beall, Christine, Thermal and Moisture Protection Manual, McGraw-Hill, New York).

parging. The first coat, called a scratch coat, should be roughened or
scratched to form a mechanical bond with the finish coat. The scratch
coat should be allowed to cure for at least 24 hours, then dampened
immediately before applying the second coat. This finish coat should
be troweled to form a dense surface, and a cove should be formed at
the base of the foundation wall to prevent water from accumulating at
the wall/footing juncture. The finish coat should be moist cured for 48
hours to minimize shrinkage cracking and assure complete cement
hydration.
Mastic or bituminous dampproofing can be applied directly to the sur-
face of concrete or masonry walls, but CABO requires that dampproofing
on masonry walls be applied over a parge coat. If a parge coat is to be
applied, mortar joints in masonry walls should be struck flush. If a bitu-
minous dampproofing is to be applied directly to the masonry, the joints
should be tooled concave. Mastic dampproof coatings can be either
sprayed, troweled, or rolled onto the surface. Some contractors apply
them by hand, smearing the thick, gooey mastic onto the wall with a

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