I'm currently building an 8' x 13.5' shed with a loft. Here is what it is supposed to look like (according to the plan):

planned shed floor

For a few reasons, the floor frame is too wide. I poured the piers slightly wide, and I couldn't find post-to-beam connectors for 6" posts to double 2x, so I used 6" to triple 2x.

I have already installed joists and blocking as shown in the picture above.

The 13.5'-long beams are each composed of three built-up 2xs. The distance between the outer edges of the innermost 2xs is 8':

shed floor

I assumed I'd be fine to build my 8'-wide shed on that red space and have a two-2x "lip" running along the sides of the shed. My next step would therefore be to screw 4x8 plywood subfloor so that it covered the innermost 2xs only.

However I'm wondering if this is safe. As I build up, will the load still be distributed laterally across the beam?

I'm hesitant to build to the full width because my materials were ordered with the 8' dimension in mind. I think building to the outer edge of the second 2x on both sides (total width 8'3") would be as far as I could go without pieces coming up short.

I don't need a building permit for something of this size, so I'm not worried about an inspection, just about structural integrity.

  • I read all that twice and still don't understand the problem. Please try to simplify a bit. What's the actual issue?
    – isherwood
    Oct 8, 2020 at 21:06
  • It would help if you'd use " for inches and ' for feet. I suspect some mismatch there. For example, a joist can't be 8 feet by 13.5 feet.
    – isherwood
    Oct 8, 2020 at 21:07
  • 1
    The piers are in but the deck is not built yet? You could put three 4"x 8" beams across your piers and then built your 13'.5" x 8' deck with joists the long way (13'.5"). Then you just have a little beam stick out on one or both sides. (and a higher then planned shed). Or just put lots of blocking in the first joist bay on the one side that does not fall on the supported rim joist and have 6" of extra deck sticking out. You do not show joists, you are planning on joists?
    – Alaska Man
    Oct 8, 2020 at 21:53
  • 1
    Sorry. Joists and blocking are in. I'll edit again.
    – fisherpeak
    Oct 8, 2020 at 21:56
  • 2
    Just leave 6" of decking protruding out one side, weather proof it and put 6' deep shelves on the outside of that wall. Everyone will think you are a genius who designed a shelf wall. (or 3' and 3" on each side for beer can collection).
    – Alaska Man
    Oct 8, 2020 at 22:17

1 Answer 1


structurally it looks ok. (assuming you'rte going to fill that 3/4" gap or put blocking in there)

8'x13'5 was going to take 4 sheets of plywood sheet 8'5x13'5 is still going to take 4 sheets.

Either use the off-cuts to fill the ends or join sheets end to end

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