Download PDF version (653k) Log In or Register to view the full article as a PDF document.

Drainage Plane Installation of the DuroScreen system begins with the base flashing, followed by the barrier paper (Figure 7).

stucco12.jpg (6393 bytes)

stucco13.jpg (8060 bytes)

stucco14.jpg (7525 bytes)

stucco22.jpg (5567 bytes)

Figure 7. Installation of the drainage plane begins with vinyl or metal base flashing (left). The building is then wrapped in felt paper or Stuccowrap, with 4- to 6-inch overlaps at the joints (middle), followed by staple-on mesh furring strips, which provide an air space behind the Durock (top right). Extra care is taken to make windows and other openings watertight (bottom right), using a self-sealing barrier tape where needed. On this job, we used 15-lb. felt paper. (As an alternative to felt paper, DuPont Stuccowrap was recently approved by USG for use with its systems. Similar to Tyvek, Stuccowrap is ribbed to encourage drainage.) The lowest course of felt is lapped over the upper leg of the base flashing, and successive courses are overlapped 4 to 6 inches. We pull the paper around outside corners and seal any holes with water barrier tape, a heavy self-sealing bituminous tape with a release sheet. At windows, doors, and other openings, we cut the felt paper horizontally at the top and bottom of the opening, then vertically down the center, and wrap it into the opening around the jack studs. To keep the drainage plane intact, however, it’s important not to wrap the felt paper around headers. Instead, we use a piece of starter track together with a special vinyl drip cap. When correctly installed, the felt covers the flanges of these flashings so that any water is channeled away from the building. Furring lath, when specified, goes on next. The special mesh strips are designed to be stapled on top of the weather-resistive barrier at each stud location to create a small gap behind the Durock. Many engineers will specify the furring lath as extra drainage insurance in a retrofit, but it’s not needed if the house is wrapped with ribbed Stuccowrap.