Hardwood Flooring February March 2018

AT THE SITE

By Brett Miller

In many situations, the installation method calls for an installation of a wood subfloor over a concrete subfloor. Different methods may be necessary depending on the subfloor system and/or the flooring being installed. Always follow the flooring manufacturer’s recommendations for adequate and recommended subfloor system requirements below their flooring. The wood subfloor panels used in these scenarios should conform to most current U.S. Voluntary Product Standard PS1, Construction and Industrial Plywood and/or most current US Voluntary PS 2, Canadian standards CSA 0151 or CSA 0121, and/or Canadian performance standard CAN 0325 (Reference: R503.2 of the 2015 IRC; 2305.1.5 of the 2015 IBC). Wood structural panels suitable for use as subflooring material should be plywood or oriented strand board (OSB) with a bond classification of Exposure 1 or Exterior. Alternative wood-based structural panels are permitted if recognized in a current evaluation report from an approved testing source as satisfying the requirements for subflooring in the governing building code. Do not use pressure treated plywood unless it has been kiln dried after treatment (KDAT), and moisture content coincides with the in-use environment of the facility in which the flooring is being installed. Amoisture control membrane is recommended any time a wood subfloor is installed over concrete. In on-grade and below-grade installations, moisture control systems are always recommended, and required when calcium chloride readings are greater than three pounds, or when relative humidity readings are greater than 75 percent. These general rules hold true for all three of the following subfloor installation methods. Installing Wood Subfloors Over Concrete Tech Troub l eshoo t i ng

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