Partner Products

We're relying heavily on various kinds of Southern Pine wood trusses to support the floors and roof of the Project House. We chose to build with trusses because they can be custom engineered to the exact specifications called for by our architect and structural engineer, at specific lengths and to carry specific loads. We chose Southern Pine trusses because of Southern Pine's high strength, durability, consistent quality and ready availability.

To build the raised floor foundation, we used open web pressure-treated Southern Pine trusses from American Truss Systems, treated by Georgia-Pacific with a copper-based preservative supplied by Chemical Specialties, Inc. The treatment for the trusses, Alkaline Copper Quat (ACQ) is a "new generation" of copper-based preservative wood treatment that is EPA-approved for residential use. Pressure-treating the lumber gives us protection against termites, rot, fungus and mold.

The open-web design of the trusses allows us to run the plumbing and ductwork through the trusses without having to cut any holes. Plus, the top chords of the truss are 3.5 inches across. That means that fewer nails will miss the nailing surface, and the gluing surface is wider and more secure. This will provide a floor sheathing connection that will be less creaky and virtually squeak-free.

To support the second floor, American Truss Systems built trusses using Southern Pine lumber supplied by Potlatch. Because trusses are not prone to shrink, warp or twist, our second floor will be solid, stable and secure. The open web structure of the trusses will be extremely convenient when it's time to run all the HVAC, electrical wiring and plumbing for the second floor. No drilling and boring will be necessary — all our mechanical elements will fit nicely through the open webs of the trusses.

To support the roof, American Truss provided custom-built trusses using Machine Stress Rated (MSR) and Machine Evaluated Lumber (MEL) from Weyerhaeuser Corporation.

At the milling stage, lumber is selected and graded using a variety of methods.

"Visually graded" lumber is assessed based on a visual inspection by a trained professional, who uses the appearance of the lumber to determine the anticipated strength properties.

Machine graded lumber, which includes both MSR and MEL, is assessed by applying forces to each piece and using mechanical stress rating equipment to measure its stiffness. MSR and MEL are basically interchangeable. The difference is that the "modulus of elasticity" (MOE) for MSR lumber is limited to .82 times the grade mean value, whereas for MEL lumber, it is limited to .75 times the grade mean. The result is that the two products will have slightly different compressive capacities. (Source: Canadian Wood Council).

Every piece of Machine Stress Rated and Machine Evaluated Lumber must also pass a visual inspection.

The bottom line, for the Project House, is that we know that every piece of lumber in the roof trusses is top-quality, high-performing Southern Pine lumber that, when built into a truss, will easily handle whatever load the truss is engineered to carry.

The American truss industry is about 50 years old, and over that time there have been significant advances in truss design. Early on, trusses tended to be simple triangular forms, providing a solid support for a roof, at whatever pitch was required, but with a uniform straight bottom chord.

The bottom chord of trusses can now be formed into curves that allow the architect to create dynamic interior spaces - like barrel vaults and sloping arches. The ability of trusses to give structural support across wide spans fits today's trend to interior designs that accentuate wide-open spaces within the home, uninterrupted by posts columns and other means of support.

Contact Information:

American Truss Systems, Inc.
(281) 442-4584

Panel Truss Texas, Inc.
(903) 657-7000

Truss Manufacturers Association of Texas
(608) 274-4849 ext.19

Southern Pine Council
(504) 443-4464

Wood Truss Council of America
(608) 274-4849

Georgia-Pacific Corporation
(800) BUILD GP

Potlatch Corporation
(888) 785-2824

Weyerhaeuser Company
(800) 643-1515

Chemical Specialties, Inc.
(800) 421-8661