I’m redoing my garage roof, which has a 12” slope over 14’. I have left over SYP 2x4’s and some microlam beams, but only enough to set at 36” OC. Can I span 36” with 2x4 SYP as my decking instead of standard sheathing at a smaller span.(Ie: 24”OC)? This has to carry a 20psf snow load.

  • P. S. I’m in a southern snow load zone 20 psf
    – Bruno
    Commented Aug 28, 2021 at 12:34
  • 1
    Think the 36 inch spacing of beams is too much in most cases. The 2x4s will be okay, but with less beams, the roof might be too weak. Your local building official would be the best person to ask. Sheeting would be too weak at 36 inches.
    – crip659
    Commented Aug 28, 2021 at 19:45
  • Depends on your applicable code, if any, and your roofing. Some types of metal roofing are self-supporting for that much span. Many are not. But most metal roofing is not suited to your less than 1:12 slope.
    – Ecnerwal
    Commented Sep 27, 2021 at 16:07

1 Answer 1


If you could, you wouldn't want to; the 36" spacing won't line up with the edges of sheet materials, like plywood for the roof or gypsum board for a ceiling. That's why 16" and 24" are the standard.

  • Think it is the other way around. Standard spacing is 16 or 24, so sheeting size matches up to those dimensions.
    – crip659
    Commented Aug 28, 2021 at 19:19
  • Chicken, meet egg, @crip659. :) Actually, I'd imagine that your way is actually the right way - stud spacing was probably standardized long before the sheet goods became available.
    – FreeMan
    Commented Sep 27, 2021 at 16:05

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