Page 329 - Construction Waterproofing Handbook

EXPANSION JOINTS 6.29
settlement during or immediately after construction. As such, these joints do not require the
movement capability of those described in the previous sections.
Often the joint is used in combination with a waterstop system as described in Chap. 2.
Figure 6.33 details the use of a foam sealant used in combination with waterstop for primary
and secondary protection. The foam sealant system can also be used in lieu of regular sealant
systems, when used in combination with waterproofing membranes as shown in Fig. 6.34.
Sheet systems are also used, including products that are designed specifically for use
over yet-uncured concrete to facilitate the construction schedule. Figure 6.35 details a typ-
ical sheet system application for below-grade applications. The sheet is some type of vinyl
or synthetic rubber and is applied directly to the concrete substrate using a cemetitious
adhesive. This system can be used where waterstop has been inadvertently left out of a
below-grade expansion joint area. Figure 6.36 shows a typical sheet system being applied.

EXPANSION JOINT APPLICATION

All joint systems require that substrates be free of all dirt, oil, curing compounds, and other
containments. Joints should be smooth, level, and straight to allow functioning and move-
ment of expansion materials. With remedial applications, irregular areas should be sawn
out, leveled, and chipped where required. If a ledge is necessary for installation, it must be
free of all fins, sharp edges, and honeycombing.
Most joint systems, with the exception of those placed into concrete, require that the substrate
be cured and dry. The various expansion systems require unique installation procedures as rec-
ommended by the manufacturer. Sealant and T-joints are applied as described in Chap. 5.
Other expansion systems are factory manufactured and require only installation of
adhesive or polymeric nosing.
Primers are generally required for horizontal sealant and T-joint applications. Polymer
adhesives may require a solvent wipe or solvent primer before application. Rubber, com-
bination, and metal systems require the installation of a blockout in the concrete substrate.
A typical blockout detail is shown in Fig. 6.37. Note that the total width is the expansion
joint system width plus 2 in for tolerance and space to adhere the joint to the substrate.
Expansion joint systems have movement limitations. If deflection or shear movement is
expected, use only materials expressly approved for this type of movement.