Page 55 - Construction Waterproofing Handbook

BELOW-GRADE WATERPROOFING 2.19
Testing of failed joints usually reveals that failures were either the cause of improperly
positioned material, Fig. 2.28, (folded over during concrete placement) or where directional
changes occurred in structure that the waterstop did not conform to. Whenever heat welding
is used, the material is adversely affected at this point and its properties are not equal to the
original material. Therefore it is recommended that whenever major directional changes are
designed into a structure, the contractor should secure prefabricated fittings. Waterstop man-
ufacturers will usually provide a variety of premolded splice pieces for directional changes,
as shown in Fig. 2.29. Also, most manufacturers will offer to custom-make the required
splices to ensure the successful applications with their material.
At all penetrations in below-grade slabs or walls, waterstop should also be installed contin-
uously around the penetration to protect against water penetration. Figure 2.30 details the use
of waterstop installed continuously around a structural steel column that penetrates the concrete
slab over the foundation.

FIGURE 2.25 Securing PVC waterstop for second con-
crete placement. (Courtesy of Vinylex Corp.)

FIGURE 2.26 Placement procedures for end bulb waterstop. (Courtesy of Tamms Industries)