Page 87 - Construction Waterproofing Handbook

2.50 CHAPTER TWO

FIGURE 2.63 Application of premanufactured drainage board in lieu of protection board to protect mem-
brane. (Courtesy of Webtec, Inc.)

Vulcanized rubbers
Vulcanized rubbers are available in butyl, ethylene propylene diene monomer (EPDM),
and neoprene rubber. These materials are vulcanized by the addition of sulfur and heat to
achieve better elasticity and durability properties. Membrane thickness for all rubber sys-
tems ranges from 30–60 mil. These materials are nonbreathable, and will disbond or blis-
ter if negative vapor drive is present.
As with thermoplastic materials, vulcanized rubbers are available in rolls of varying
widths. Seam sealing is by a solvent-based adhesive, as heat welding is not applicable. A
separate adhesive application to vertical areas is necessary before applying membranes.
Vulcanized rubber systems incorporate loosely laid applications for horizontal installations.
Although other derivatives of these materials, such as visquene, are used beneath slabs as
dampproofing membranes or vapor barriers, they are not effective if hydrostatic pressure
exists. Material installations under slabs on grade, by loose laying over compacted fill and
sealing joints with adhesive or heat welding, are useful in limited waterproofing applications.
This is a difficult installation procedure and usually not specified or recommended.
Loosely laid applications do, however, increase the elastomeric capability of the mem-
brane, versus fully adhered systems that restrict membrane movement.

Rubberized asphalts
Rubberized asphalt sheet systems originally evolved for use in pipeline protection appli-
cations. Sheet goods of rubberized asphalt are available in self-adhering rolls with a