I am building a foundation for a 10x12 metal/vinyl coated shed. The foundation is ready with four 12" diameter concrete pillars and another three pillars down the center. I used concrete strong tie anchors in the wet concrete that accept a 4x4. I am using (3) 4x4's that I will place over and anchor to the concrete pillars. The pillars are elevated at least 12" on the high side and 4" on the low side for no ground contact and good drainage underneath. I plan on just placing the assembled 2x6 frame on top and nailing it to the 4x4's.

I was looking for some pointers on the following:

  1. How to make sure it's square?
  2. How to make sure the joists are level with the header boards
  3. Should I go 16 on center or 12 and what size nails or screws?
  4. Do I use joist hangers and hurricane ties (between joist & 4x4's)?
  5. Do I need to use blocking for better support?
  • Checking square is as easy as comparing the length of cross diagonals. – Skaperen Aug 12 '12 at 20:37
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    A picture or diagram would help. – BMitch Aug 12 '12 at 21:57
  • I'm concerned about your use of 4x4's here. Please add a diagram of some sort showing the exact layout of the foundation elements and your planned framing. – mac Aug 14 '12 at 18:45
  1. Measure the 2 diagonal distances to the corners. If the measurements are not the same, the floor is not square.

  2. Not sure what you are levelling to. A level, framing square, and careful measuring solves most layout problems.

  3. 16" spacing is fine as long as your sheathing is rated for 16" spans. Sounds like they are spanning about 6 feet? 16d common nails (3-1/2") are usually used for framing. I'm concerned with spanning 10 feet with 4x4s supporting 3 feet of contributing floor load. Plus wall dead weight and maybe supporting the roof? I'm pretty sure if you checked a load table, this is inadequate.

  4. Hangers are not needed since the joists sit on top of the 4x4s. Tie downs from joist to 4x4 is a really good idea. 32 inch spacing along each 4x4 should do it.

  5. Block between joists at all supports. This is a typical code requirement.

  • "Box" or "sinker" nails are typically used for framing, and they're usually cement-coated. "Common" nails have heavy, old-school shanks that are more likely to split lumber. – isherwood Feb 22 '18 at 21:26
  • Blocking is only required if tongue-and-groove sheathing isn't being used. – isherwood Feb 22 '18 at 21:27

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