Page 57 - Construction Waterproofing Handbook

BELOW-GRADE WATERPROOFING 2.21

FIGURE 2.28 Improperly positioned, placed, and secured waterstop. (Courtesy of Coastal Construction
Products)

FIGURE 2.29 Typical manufactured PVC waterstop splices and transition pieces. (Courtesy of Tamms
Industries)

It is imperative that the hydrophilic and bentonite materials are not left exposed to rain-
fall before concrete is placed. If this occurs, the material will swell and lose all its capabil-
ity to seal the joint after concrete placement. The photographs in Fig. 2.33 show a typical
waterstop installation using a swelling material that is adhered to the substrate with sealant.

CAPILLARY ACTION

Construction details must be included to prevent natural capillary action of soils beneath
foundations or below-grade floors. Capillary action is upward movement of water and
vapor through voids in soil from wet lower areas to drier high areas. Capillary action is
dependent upon the soil type present. Clay soils promote the most capillary action, allow-
ing more than 10 ft of vertical capillary action. Loose coarse gravel prevents capillary
action, with this type of soil promoting virtually no upward movement.