- Q.A client has asked me to
build a practical outbuilding with a wood floor system.
For simplicity's sake, I'd like to place it on a
Sonotube foundation and use continuous-span wood
I-joists. The bottom of the I-joists will be about 16
to 24 inches off the ground, and the perimeter joists
will be completely protected from the weather by the
siding and water table. Is it okay to use I-joists in
this situation?
A.Jeff Olson, an engineer
with Boise Cascade in White City, Idaho,
responds: Although it's always best to consult
with your local building official, I know of no
limitations on the use of I-joists in this
application. Many homes built on pilings in coastal
areas have I-joist floor systems; raised
pier-and-beam foundations (using either engineered
or sawn lumber floor framing) are a popular
alternative to concrete slabs all along the Gulf
Coast. Keep in mind, however, that floor joists
should be no closer than 18 inches to grade, and
beams and girders should be no closer than 12
inches to grade. Local jurisdictions may have
additional requirements for flood-plain areas.
For more information on raised-floor framing
techniques, go to www.raisedfloorliving.com, a Web
site sponsored by the Southern Pine Council.