|
Raised Floor Foundation Under the Project House
The 2002-2003 Project House is a 5,800 square foot Mediterranean style custom
home, designed by the Evans Group of Florida.
Due to the expansive nature of the soil in the area in which we're building,
our engineer recommended that we build the house on a classic pier and beam
foundation.
We partnered with the Southern Pine Council and a number of their member companies
to construct a raised wood floor foundation that will not only stand the test
of time, and whatever stresses the expansive clay soil can throw at the house,
but will also ensure that the family living in the home will have a comfortable
surface to live on, one that is solid and stable, but has a little give and
is never damp.
Construction of the Foundation
We leveled the lot to a depth of one foot, then a drilling crew came in and
drilled 105 piers, 12 inches wide, to a depth of 13 feet. After the initial
hole was drilled, the crew went back in with a "belling tool" and
hollowed out a 36" bell-shaped area at the bottom of the pier. Then, the
pier holes were filled with concrete and reinforced with rebar. This "bell"
shaped bottom gives the piers greater resistance to the up and down motion of
the expanding and contracting clay soil.
Forms were set atop the piers around the perimeter of the house and in the
interior where load bearing walls would rest. Concrete was poured into the forms,
and when the concrete hardened, the forms were removed and the house was ready
for wood.
Southern Pine Glulam Beams and Pressure Treated Trusses
Anthony Power Beam® glued laminated beams were used to support
the load-bearing areas in the home's interior. These massive beams are made
by gluing and stacking 2"x4" or 2"x6" Southern Pine finger-jointed
boards together, applying pressure, then drying, shaving, and laminating the
resulting beam, which can be custom-cut to lengths up to 60 feet. This type
of engineered wood construction, using easily renewable "new growth"
trees, is much easier on the nation's forest resources than cutting massive
solid-sawn structural beams from old-growth timber.
Between the Powerbeam® glulam beams, we placed custom-built
pressure-treated Southern Pine parallel chord trusses using wood from the Georgia-Pacific
Corporation and Alkaline Copper Quat (ACQ) treatment from Chemical Specialties,
Incorporated. The trusses were built by American Truss Systems, Inc. to dimensions
specified by our foundation engineer.
Alkaline Copper Quat is a new-generation wood preservative that is EPA-approved
and extremely suitable for residential uses. The primary active ingredient in
ACQ is copper, which gives the treated wood a marked greenish tint. We used
treated lumber in the trusses for protection against termites and mold.
The top chords of the trusses are 3 ½ inches across, which will give
us an exceptionally stable surface area for supporting the subfloor.
The spaces between the chords allow the plumber and electrician to run all
utilities between the truss chords, which will allow for easy access and maintenance
in the coming years. There is a 19" crawl space between the bottom of the
trusses and the ground. We covered the ground under the truss system with a
poly plastic barrier, topped by two inches of pea gravel.
Once the trusses and glulam beams were in place, our framing crew glued, nailed
and screwed into place the ¾ inch "Oxtreme" Sturd-I-Floor Oriented
Strand Board subfloor from the Potlatch Corporation, completing our custom-engineered
Southern Pine raised floor foundation.
Contact Information:
Anthony Forest Products Company
(800) 221-2326
Georgia-Pacific Corporation
(800) BUILD-GP
Chemical Specialties, Inc.
(800) 421-8661
American Truss Systems, Inc.
(281) 442-4584
Panel Truss Texas, Inc.
(903) 657-7000
Southern Pine Council
(504) 443-4464
Truss Manufacturers Association of Texas
(608) 274-4849 x19 |
