Page 418 - Construction Waterproofing Handbook

10.20 CHAPTER TEN

FIGURE 10.20 Sealant used for penetration, transition, detailing. (Courtesy of Emseal)

properly as described in Chap. 5. Figure 10.24 shows the correct use of sealant as a ter-
mination detail for waterproofing membranes.
Precast panel construction with porous finishes allows water transmission directly
through the panels, bypassing joint sealants. Absorption of water through panels is further
enhanced by negative air pressure between the exterior and interior areas. This uneven air
pressure causes water to be drawn into a structure by a suction process. Likewise, wind-driven
rain forces water through minor cracks and fissures in a masonry or concrete structure.
These natural phenomena are addressed by double-sealing joints, with sealant being
applied to both exterior and interior sides of panelized construction. This double sealing
allows air pressure in wall cavities to remain relatively constant by pressure-equalizing the
sealed space between exterior and interior areas. Double sealing also provides additional
air-seal protection for buildings, reducing heating and cooling costs.