Page 172 - Construction Waterproofing Handbook

ABOVE-GRADE WATERPROOFING 3.61

FIGURE 3.49 Flood coat application of clear deck sealer.
(Courtesy of Saver Systems)

are chosen in much the same way as below-grade applications. These installations require
a protection layer, since these materials cannot be subjected to traffic wear or direct expo-
sure to the elements. As such, a concrete topping slab is installed over the membrane, sand-
wiching the membrane between two layers of concrete; hence the name sandwich-slab
membrane. Figure 3.51 details a typical sandwich-slab membrane.
In addition to concrete layers, other forms of protection are used, including wood decking,
concrete pavers (Fig. 3.52), natural stone pavers (Fig. 3.53), and brick pavers (3.54). Protected
membranes are chosen for areas subjected to wear that deck coatings are not able to withstand,
for areas of excessive movement, and to prevent the need for excess maintenance. Although
they cost more initially due to the protection layer and other detailing required, sandwich
membranes do not require the in-place maintenance of deck coatings or sealers.
Protected membranes allow for installation of insulation over waterproof membranes
and beneath the topping layer (Fig. 3.55). This allows occupied areas beneath a deck to be