OSB subfloor notches moi$ fighting inno

dust or adhesive, and allows water to drain even if the panels are not properly gapped. Preventing standing water reduces water absorption and helps maintain the floor system's integrity.

"The new Down Pore technology removes the need to sweep pooled rainwater off the floor or drill holes to let it through," said Bob Olson, engineering & technical director for Weyerhaeuser OSB. "Our new self-draining panel design removes water quickly, reducing the drying time needed before installing finishing materials. That can save several days or more during construction. Plus, our proprietary edge sealant also saves builders time and money since they do not need to sand panel edges to achieve a smooth surface."

Other recent enhancements to Edge Gold panels include a proprietary edge seal formulation that significantly reduces edge swell, and extension of Weyerhaeuser's "no sand" guarantee for the panels from 90 days to 200 days.

tTtHe KNocK oN OSB has traditionally been its susceptiI Uitlty to moisture. When the panels get wet, their edges swell. Consequently, home builders often must sand OSB subflooring to ensure their floors are flat.

But moisture-fighting innovations over the last several years have helped OSB take over a majority of the subflooring market. And, the upgraded panels have dealers again marketing OSB as a premium, instead of a commodity, product.

Most recently, Weyerhaeuser has added another feature to its premium Edge Gold flooring panels to further enhance the panels' resistance to rain and moisture. The company's new Down Pore self-draining technology channels water from the panels' surfaces and drains it off the joists below. Along with a high-performance edge seal, this helps reduce construction delays for contractors during inclement weather.

The Down Pore technology consists of three specially shaped drainage grooves on one of the narrow ends of each 4x8 panel. The unique design resists clogging from saw-

The move follows on the heels of Ainsworth's introduction last year of its PointSIX subflooring. It features a patented tapered-edge technology whereby a thin layer of the highly compressed fiber along all four edges of the OSB panel is milled off, removing the part of the subfloor that's most prone to swelling. PointSIX takes its name from research results indicating a .6mm taper depth to be the most effective in reducing edge swell.

The taper on PointSIX is almost imperceptible, and it's a dimension that won't require sanding. With moisture, the wood fibers expand to essentially "fill up to flush" the micro-taper. If no moisture contacts the engineered subfloor, it does not require any filler or mastic. APAapproved for structural integrity, PointSlX features a precise tongueand-groove profile for a secure fit.

According to Mark Sutherland, Ainsworth's general manager of marketing, "We created PointSIX and its patented edge taper to accommodate the effects of moisture and put an end to a problem that builders have long struggled with: OSB edge swell. The industry response since the product's introduction has exceeded our expectations, with our dealer partners reporting positive feedback from customers who no longer have to factor edge sanding into labor and budgets. More important has been what we haven't heard: Since introducing pointSlX, we've received noticeably few callbacks due to edge swell or other moisture-related problems."

Huber has long marketed its AdvanTech, Norbord its Stabledge, and LP its TopNotch subflooring as premium products that offer minimal water absorption, SO-year warranties, and guarantees against the need for sanding. (TopNotch, in fact, gets its name in part from its RainChannel notch system that helps protect the OSB against moisture absorption and edge swell.)

They and other OSB manufacturers continue to improve their resins, sealants, and manufacturing processes, committed to making OSB a maximum-value-added building product.

By Carla Waldemar