One of the questions that inevitably surface at my EIFS seminars involves the use of joints at floor lines in wood-frame buildings. This particular detail, although not difficult to construct, is so aesthetically objectionable to some people that they simply refuse to include them on the building. Not using floor-line joints is risky but sometimes you can get away with it. This month’s column discusses why they are needed and various options for using, or not using, them.
Horizontal joints are needed at the floor line in wood-frame buildings for the simple reason that wood changes its dimensions as its moisture content changes. The change in dimension of the wood causes forces to be developed in the EIFS that can lead to cracking. This issue does not exist when metal framing is used because the dimensions of the metal remain constant throughout its life.