A. Corresponding editor Paul Fisette responds: I would install the underlayment panels perpendicular to the joists, the same direction as the subfloor. It is a good idea to stagger the joints — both the end and edge joints — by at least 6 inches. Most handbooks do not require that you "hit" the underlying joists with the underlayment. Personally, I prefer to have the end-joint hit a joist, so I would offset the ends of the panels by 16 inches.
APA—The Engineered Wood Association has a good publication called The Design/Construction Guide: Residential & Commercial that has a lot of very good information about many floor, wall, and roof applications. The publication addresses recommended installation details, including nail spacing, for the installation of underlayment. To order the...
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