Change comes slowly to the construction industry, as builders often stick with what they know best to lower their risks. But change does come, and the current labor shortage is encouraging builders to use products that make tighter, more energy-efficient building enclosures in less time. Industry analysts call it “multi-functionality” or the “systems approach,” but the result is enhanced sheathing, insulation, and weather-resistive barriers (WRB) that help builders do more in less time by combining several steps into one.
At the same time, manufacturers are introducing products that help builders meet growing expectations for tighter, better-insulated enclosures. “Anything you can do to take time off the application of a product ... a builder is likely to look at it,” says Nancy Musselwhite, an industry analyst with Principia.
Sheathing That Does More
Huber Engineered Woods has had a runaway bestseller with its Zip System sheathing for both walls and roof. It combines structural sheathing and a coating that eliminates the need for a separate WRB. When used with a proprietary sealing tape, the sheathing is an effective air and moisture barrier.
Huber dominates this part of the sheathing market, but it’s not alone. Georgia-Pacific introduced a product called ForceField. There also are entries in the coated sheathing category from Ox Engineered Products (Thermo-Ply) and Roy O. Martin (Eclipse, a radiant barrier).
Using these products saves a builder time. They make it easier for contractors to meet air-tightness standards in newer model building codes and pass green certification standards. The treated sheathing also provides an integral layer of moisture protection; unlike roofing shingles and roofing underlayment, it probably won’t blow off in a big storm.
Huber now offers a version of its Zip sheathing that comes with a layer of polyisocyanurate insulation to reduce thermal bridging. Zip System R-sheathing, which comes in four thicknesses and with R-values of up to R-12, is the fastest-growing product in its portfolio.
Manufacturers continue to broaden WRB offerings that are applied beneath the cladding, a category that DuPont started with the commercialization of Tyvek 50 years ago. Other manufacturers in the category include James Hardie, Fiberweb, CertainTeed, Owens Corning, and Dow.
RainDrop 3D in Kingspan’s GreenGuard product line is a newer entry. RainDrop has a textured surface that enables any water getting past the cladding or flashing to drain away, even when siding has been nailed tightly against it, according to the manufacturer. The product would appear to be aimed at builders who now apply cladding over a vented rainscreen, as it combines two steps (applying a WRB and then furring strips) into one. Flashing and sealing tapes also are becoming more widely used.
What’s New in Insulation
Developments in thermal insulation are more about incremental changes rather than revolutionary steps, but green-building advocates have to be pleased with announcements from both Rockwool (formerly Roxul) and Owens Corning that binders containing formaldehyde are being phased out of some of their products.
This spring, Rockwool said the changes would initially affect its light-density AFB batt insulation, in part to allay concerns among builders and designers that formaldehyde off-gassing from mineral wool insulation posed health risks.
Owens Corning said the no-added formaldehyde binders would be used in its Thermafiber insulation. Those steps will be welcome news for anyone trying to meet the rigorous requirements of certification programs such as the Living Building Challenge, or gain air quality points under the Leadership in Energy and Environmental Design (LEED) and similar programs.
Manufacturers of fiberglass batt insulation have already moved in that direction. Look for a bigger push into U.S. markets from Rockwool with a new $150 million, 150-employee plant in Jefferson County, W.Va., due to open in the first quarter of 2020, says Musselwhite.
Firestone Building Products is set to launch a reformulated polyisocyanurate board insulation that improves low-temperature performance. Insulation Product Manager Edward Klonowski says its rebranded Isogard and Enverge boards test at R-6.3 per inch at 40 degrees while the R-value per inch in earlier versions dropped to R-5 per inch at that temperature.
CertainTeed has introduced two new types of fiberglass batt insulation: EasyTouch, which comes with a perforated plastic film coating to reduce dust and make installation less itchy; and SmartBatt, which incorporates a smart vapor barrier to limit vapor transmission into wall cavities when humidity in the walls is low.
Framing Developments
Basic framing doesn’t change quickly—witness the painfully slow adoption of optimum value engineering—but manufacturers have updated several products that improve durability or save time.
Weyerhaeuser introduced a new coating for its Trus Joist Eastern Parallam PSL beams and columns that curbs moisture absorption while in the yard and during construction. Eastern Parallam PSLs are available east of the Mississippi and are made for interior use.
Boise Cascade increased production of its AJS 24 FMJ I-joists, designed for use in unfinished basements. The I-joists have a foil coating to meet the ASTM fire test, and have no specific top and bottom orientation to make installation a little easier.
Louisiana-Pacific hopes rising framing lumber prices will convince more builders to use its LSLs in selected areas of the house—on kitchen walls, for example—where straight and plumb are worth a few extra bucks. Reid Williams, an application engineer at LP, says the company’s biggest challenge is to convince builders to use a value-added product. But when LP gets a chance to engineer a job and save the builder money, he adds, “it’s usually a slam dunk.”
Rising lumber costs should make light-gauge steel framing more competitive, but even the head of the Steel Framing Alliance doesn’t see a dramatic change in its residential market share of 1% or less.
More Prefab Ahead?
A more fundamental change may come with wider adoption of panelized building components. The Modular Building Institute would like to double the current 3.5% prefab market penetration by next year, says Principia’s Susanna Ross. That would be a big improvement, but still would leave the U.S. far behind Canada and Europe.
Once derided, “prefabrication has become a rather sophisticated method of manufacture to improve lead time, quality of construction, and availability of labor,” she says.
