Durajoint EXPAND-Tite is a flexible concrete construction joint waterstop that is easy to install in non-moving joints. It is composed of bentonite clay and butyl rubber to withhold its physical integrity after expanding. EXPAND-Tite expands in a controlled fashion when exposed to moisture and will not expand beyond a point where the hydration process reduces the effectiveness of the waterstop. When installing EXPAND-Tite the concrete surface needs to be dry and free of contamination. EXPAND-Tite Primer is also recommended before the placement of the waterstop.