As larger-sized dimensional lumber becomes harder to find, manufacturers have stepped up to fill the void. The result: a large breadth of engineered structural lumber products available to builders. It all depends on your preferences and your needs, but chances are there is a product out there for you.
"We have seen a high rate of acceptance for engineered wood I-joists," says Kevin Hayes, advertising and publicity manager for APA--The Engineered Wood Products Association in Tacoma, Wash. "I-joists are lighter in weight and have higher load-bearing capacities than solid-sawn 2x10s or 2x12s."
According to APA, engineered I-joists, which comprise top and bottom flanges of various widths united with webs of various depths, resist common bending stresses, and the web provides outstanding shear performance. Manufactured with solid-sawn lumber or structural composite lumber and plywood or oriented strand board, engineered I-joists allow manufacturers to make the most efficient use of wood.
Boise, Idaho-based Boise Building Solutions Manufacturing recently added such a new product to its family of engineered structural lumber. The AllJoist AJS 5 series features solid-sawn flanges made from black spruce--a denser wood than traditional species, making it more dimensionally stable. The product also has been purposely designed for greater shear capacities than 2x10 and 2x12 dimensional lumber joists, the company says.
Another type of structural joist that builders have at their disposal is the trimmable variety, which marries an open-web truss to a solid-web "I" section. The ends of these types of products can be trimmed up to 12 inches on the jobsite. "These joists have always been a custom product, but we now mass-produce them, which has greatly diminished the lead times for builders," says Barry Sanford, president of TrimJoist Corp. in Columbus, Miss.
Sanford says trimmable joists were used primarily in multifamily construction because fabricators preferred the large orders that big jobs tend to yield. Though residential builders liked the joists, they were turned off by the expense and the long time it took to have them delivered. "All kinds of problems could have come up by then," Sanford says, such as inaccurate measurements or changes in the floor plan, resulting in a product that did not fit.
But TrimJoist's TrimEnds allow the truss to be trimmed on site for an exact fit, and unlike solid-I-type joists, the product features strut webbing, which enables the builder to run plumbing, electrical, and duct work.
"You cannot overestimate the cost and time it takes to cut those holes in a solid-I joist," says Roger Gibbons, president of SpaceJoist in Arlington, Texas. "You often cannot control the trades in cutting those holes," he adds, "and there is often a lot of repair to do." Another benefit to open-web design, Gibbons says, is the elimination of drop-down ceilings. As a result, houses can have higher ceilings.
Trimmable joists generally cost about 5 percent to 20 percent more than traditional solid I-joists. That premium and the relative newness of the category mean the market share is small. "People think we are ahead of our time," Gibbons says, "and growth is expected to shoot right up in the near future."
What else does the future hold for structural lumber? Kurt Koch, general manager of the frameworks group at Trus Joist in Boise, says pre-assembled panels already are picking up traction with many builders.
"Builders can now order wall panels with all studs and rough openings pre-cut for the carpenter to assemble," Koch explains. These panels, he says, result in easier installation for a less sophisticated workforce--builders become assemblers rather than craftsmen--reduced cycle times, and a more consistent product, since pieces are manufactured in a controlled factory environment. The next step in the evolution of this idea would be floor panels that also come pre-assembled.
Trim down: The manufacturer's products feature ends that can be trimmed at the jobsite, strut webbing, and a 3 1/2-inch flange on top and bottom, which offers a wider surface for more glue and for more accurate nailing. Each end section also uses 23/32-inch-thick oriented strand board so the use of compression or "squash" blocks is almost entirely eliminated. The manufacturer says the joists are stocked at any authorized dealer, so there are no lead times. TrimJoist. 800-844-8281. www.trimjoist.com.
Open sesame: SpaceJoist TE is a product that combines the best features of an open-web floor truss and a wood I-joist. It can be trimmed up to 12 inches on each end to offer flexibility at the jobsite, and the open-web design allows builders to run wiring, plumbing, and HVAC components. It also has wide flanges that help eliminate squeaks, the company says. SpaceJoist TE. 800-521-9790. www.spacejoist.com.
Spruce up: The AllJoist AJS 5 series I-joist is the newest introduction from the manufacturer. The product has a solid-sawn flange made from black spruce, a much denser wood than traditional species, the company says. It is stiffer than dimensional lumber, which results in a higher floor performance, according to the manufacturer. In addition, it will not shrink or twist and can be used in continuous span applications. Boise Building Solutions Manufacturing. 800-232-0788. www.bc.com.
Jump for joist: The manufacturer's I-joist features laminated veneer lumber flanges and an oriented strand board web. Dimensionally stable, the product will not warp or bend and uses up to 50 percent less wood fiber than conventional lumber joist, the manufacturer says. The product is available in lengths of up to 66 feet, with flanges measuring 3 1/2 inches, and in various depths. Roseburg Forest Products. 541-679-3311. www.rfpco.com.
Flange candidate: TJI joists now feature flanges made from the company's TimberStrand laminated strand lumber (LSL). Unlike conventional I-joist flanges made from sawn or laminated veneer lumber, TimberStrand LSL is made from aspen and poplar that have been converted into high-strength, defect-free engineered lumber, the manufacturer says. The joists are available in a variety of depths and lengths for either floor or roof applications. Trus Joist. 800-338-0515. www.trusjoist.com.
For more product information, visit Hanley-Wood's interactive product catalog, ebuild on BUILDER Online.
Learn more about markets featured in this article: Boise City, ID.