Page 178 - Construction Waterproofing Handbook

ABOVE-GRADE WATERPROOFING 3.67
or structural movement of the topping slab.
This can cause the topping slab to crack,
leading to membrane deterioration. Refer to
Figs. 3.62 and 3.63 for proper detailing.
Membranes should be adhered only to
the structural deck, not to topping layers,
where unnecessary stress due to differential
movement between the two layers will
cause membrane failure.
Waterproof membranes should be ade-
quately terminated into other building enve-
lope components before applying topping
and protection layers. The topping is also
tied into the envelope as secondary protec-
FIGURE 3.59 Premanufactured drainage for sand- tion. Control or expansion joints are installed
wich-slab construction. (Courtesy of American
Hydrotech) along topping slab perimeters where they
abut other building components, to allow for
adequate movement (Fig. 3.64). Waterproof
membranes at these locations are turned up
vertically, to prevent water intrusion at the
protection layer elevation. Refer to Fig. 3.65
for a typical design at this location.
When pavers are installed as the protec-
tion layer, pedestals are used to protect the
membrane from damage. Pedestals allow
leveling of pavers, to compensate for eleva-
tion deviations in pavers and structural
slabs (Fig. 3.66).
At areas where structural slabs are sloped
for membrane drainage, pavers installed
directly over the structural slab would be
unlevel and pose a pedestrian hazard.
Pedestals allow paver elevation to be leveled
FIGURE 3.60 Topping slab with tile perimeter edge at these locations. Pedestals are manufac-
detail that permits drainage. Note drainage board tured to allow four different leveling applica-
over membrane, and provision to weep water out of
envelope at edge. (Courtesy of Schluter Systems) tions, since each paver typically intersects
four pavers, each of which may require a dif-
ferent amount of shimming (Fig. 3.67).
If wood decking is used, wood blocking should be installed over membranes so that nailing
of decking into this blocking does not puncture the waterproofing system. Blocking should run
with the structural drainage design so that the blocking does not prevent water draining.
Tile applications, such as quarry or glazed tile, are also used as decorative protection
layers with regular setting beds and thin-set applications applied directly over membranes.
With thin-set tile installations, only cementitious or liquid-applied membrane systems are
used, and protection board is eliminated. Tile is bonded directly to the waterproof membrane.