carpentry question

[Art]

We are replacing part of a bathroom floor along side a non support wall. This is because the floor was not installed level and also suffered water damage. The carpenter said we should put blocking under the wall between joists since we will be cutting the plywood subfloor next to it and the wall might eventually sag without the blocking. I certainly agree. The question I have is should the plywood be just laid and nailed on top of the blocking or should we add blocking perpendicular and between those first blocks so the cut edge of the plywood has something to sit on. Thanks for your advice.

[Joseph Meehan]

Assuming that it is the usual 16" OC, it really should not be a problem. There will be no such blocking where two plywood panels meet in the middle of the room.

[Joe]

The more edges you tie together in floors, walls, whatever, the stronger the structure will be. Applies to drywall, too. Your intuition on this one is absolutely correct. Keep in mind that construction adhesives add tremendously to overall quality and that is why more and more quality homes are being litertally glued together thse days. HTH

Joe

[Art]

We will not have the advantage of tongue and groove fit though as would be normal where plywood panels meet in the middle of the room in new construction so that is why I am concerned.

[dpb]

Even in new construction w/ T&G or not the edges of subflooring (that _is_ what you're talking about, right?) are not "left hanging" between joists in any reasonable construction--the sheets are trimmed to meet on a joist.

If your retrofit can't cut back to an existing joist for some reason, then certainly there should be blocking at the joint(s) of adjacent sheets to avoid the otherwise inevitable springiness that a cantilevered sheet edge would otherwise be. It seems unlikely in most cases one couldn't simply go back to the next joist, however.

If you're talking cross-joists and not with the joist direction, then you're only talking a 16" span and probably can get by, but if there's access to insert blocking, can't hurt and can't cost much.

imo, ymmv, $0.02, etc., etc., ...

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