Add cross-framing under toilet?

[speede541]

As part of my little project I'm replacing a small square of rotted floor under a toilet -- a double layer of 3/4" ply, in fact -- spanning about 14" between parallel joists.

Do any of you routinely install cross bracing to span between the joists for a bit of extra support under the toilet? It seems pretty beefy without, but I'm curious about best practices.

[jadnashua]

Ply is strongest if it spans at least two bays (i.e., attached to three joists). So, since you'll have some edges unsupported, consider blocking along those edges.

[jimbo]

I agree with jad's comments. I have found over the years, that for a drywall repair, or a flooring repair....a bigger patch is actually easier, stronger, and ends up better on the cosmetic front.

A 14" square of plywood, just supported by a 3/4" lip at the joist, will be prone to sag along the open edges,and pry up on the supported edge.