I'm going to lay my 3/4 plywood sheathing subfloor perpendicular across my floor joists. My floor is 10x16.

I've read to use full sheets and avoid using half/cut sheets as well as not having the seams all line up between the sheets and needing the seams to stagger.

Since sheets are 8' and my building is 16' it seems (no pun intended) there's no great way to not have one big seam run down the middle of the floor. Or cut into smaller sheets to avoid?

  • Half sheets are correct for every other row here. Tongue and groove edges will also help, if you can get them.
    – Ecnerwal
    Commented Jun 16, 2023 at 16:17

1 Answer 1


It seems the general practice is to avoid 'running' seams at all costs. Cut some panels down: enter image description here

  • 3
    The general idea is to use the long dimension of the plywood to maximum benefit by joining as many joists as possible to one piece. In this picture, assuming the joists go side to side, you achieve the best compromise. Every joist is joined to SEVERAL adjacent joists on both sides by a long piece of flooring at least somewhere along the joist. No joist has a seam along its entire length. No board is cut very small. You want to achieve that balance.
    – jay613
    Commented Jun 16, 2023 at 14:48
  • thank you, this is perfect. it sounds like a few more seams is the lesser of evils Commented Jun 16, 2023 at 21:42

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