Page 67 - Construction Waterproofing Handbook

BELOW-GRADE WATERPROOFING 2.31

FIGURE 2.38 Spray, trowel, and brush applications of cementitious waterproofing. (Courtesy of Vandex)

It is advantageous to install negative cementitious systems after a structure is completely built.
This allows structural movement such as settling to occur before application.
A typical installation for all cementitious systems is elevator and escalator pits similar
to Fig. 2.39, which details the installation for this type application. Note that the system
calls for two coats with no protection course and the typical cove detailing at the wall-floor
intersection. This detailing would be improved by the installation of waterstop at these
intersections. Some cementitious manufacturers will permit the use of their product to sup-
plement protection of these intersections when waterstop is not used, as shown in Fig. 2.40.
In this detail, the cementitious product is installed continuously on the floor-foundation
slab under the wall area intersection. Further protection could be added by installing pre-
manufactured drainage systems on the walls and below-slab locations.
While not often recommended for below-grade applications subject to hydrostatic pres-
sure, concrete block walls are sometimes used as the wall component. The mortar joints are
the weak points in this design, and cementitious systems often are not able to protect against
the settlement cracking that occurs. Typically, fluid-applied membranes or sheet-good sys-
tems would be preferred; however, some cementitious manufacturers do provide detailing
for this type of installation, as shown in Fig. 2.41. Note that the cementitious system is
applied as a positive system in this situation, with two heavy slurry coats applied to afford
the necessary protection required. Also note that a cove cant is added to the exterior side
also at the wall-floor intersection in addition to the cove installation on the floor-wall neg-
ative application. Since waterstop is not applicable for the concrete block, the manufacturer
prescribes a detail coat of the material on the foundation before block is laid. A drainage