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subfloor

Of interest, we just discussed this issue. According to an APA spokesperson, subflooring (and here we assume plywood) generally runs perpendicular to the joist direction. This is the best structural situation. However, where there is a change in joist direction, for instance at a cantilevered situation where there are different forces being applied to the supporting joists or beams, for architectural reasons, it is best to have the plywood subflooring span over the change in joist direction. By spanning over the change, one reduces any potential difference in deflection of the adjacent joists. However, the unsupported edges of the plywood that would normally fall on a joist must then be supported by additional blocking.