A. John Edgar, senior technical services manager at Sto Corp., a manufacturer of EIFS systems, responds: When EIFS is installed on a wood-frame building, EIFS manufacturers recommend the installation of a horizontal joint in the sheathing at floor lines (see “Success With EIFS,” 11/01). The purpose of the joint is to accommodate the cross-grain shrinkage in the floor joists, as well as any settling. (This type of shrinkage can cause problems with many types of cladding, including EIFS, brick veneer, and vinyl siding.) In addition to providing a gap in the sheathing, a flexible joint is provided in the EIFS cladding, to accommodate the movement that occurs as the sheathing joint closes.
This standard detail is problematic when the sheathing spans the floor line to structurally tie the upper floor to the lower floor, as is often the case in seismic zones and high-wind coastal areas. In such cases, the EIFS joint should be installed at the nearest horizontal joint in the sheathing, even if that is not at the floor line. As the...
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