Finger-Jointed Studs

A.Paul Fisette, director of Building Materials and Wood Technology at the University of Massachusetts Amherst and a JLC contributing editor, responds: Besides being resource-efficient, the use of finger-jointed wall framing provides straighter, better walls — but if your studs are rated "for vertical use only," then the short answer is no.

While the IRC (2006, R602.1.1) allows graded finger-jointed lumber to be used interchangeably with solid-sawn members of the same species and grade, "for vertical use only" means this engineered product is equivalent to "stud"-grade lumber (the grade stamp should also indicate "stud"). Stud-grade lumber can have knots and other strength-reducing characteristics that compromise performance under bending stresses but not in compression. Both finger-jointed and sawn studs are strong enough for short-term bending or tension loads (from wind, earthquakes, and impact, for instance), but not for long-term exposure.

Practically speaking, continuously supported bottom plates and top plates with upper-level joists or rafters oriented directly over studs are not subject to continuous bending loads, so you could try to seek approval for this use of stud-grade lumber on a case-by-case basis from your building inspector. But the material is not meant for this purpose, and it comes in only 10- and 12-feet lengths, which is not ideal for most plate applications. If you want to use finger-jointed top plates, it's better to specify structural finger-jointed lumber (labeled "CERT EXT JNTS").

A final caveat: Finger-jointed studs can't be used in fire-rated assemblies unless they are labeled HRA (heat-resistant adhesive).