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Boards are used as shelf decking. Each end rests on beams that have a 7/8" lip. We use 2x8", 2x10", and 2x12" pine boards of approximately 40" in length. I have not been able to locate a formula for pine laid flat. If anyone can point me in the right direction that would be helpful. Diagram below.

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FreeMan
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Dennis Cahalane
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  • Not quite sure where to find it, but maybe look for load bearing of steps. With 1 1/2 thick wood, a 2x, would feel quite safe walking and maybe taking small jumps on it at 40 inch spans. So maybe a plus 200 pound standing/dead load. – crip659 Apr 06 '22 at 11:28
  • I meant a spread out load, not one that is at a point or very small area. – crip659 Apr 06 '22 at 11:53
  • if you have a formula, you just need to use the right numbers for it being "flat" rather than the assumed vertical loading. this one is useful in practice for shelving, since sag becomes objectionable well before breaking: https://woodbin.com/calcs/sagulator/ or – Ecnerwal Apr 06 '22 at 12:00
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    Here's one where you can flip the dimensions around to make it flat, for uniform loading, with "easy input" species data. Same place also has various point loading setups but you have to input the lumber data. http://www.timbertoolbox.com/Calcs/ddsimplebeam.html – Ecnerwal Apr 06 '22 at 12:52
  • Those boards should be able to hold **a lot**. Typical shelving for books (which are quite a heavy load) is 3/4" or 1", and you've got 1-1/2" – manassehkatz-Moving 2 Codidact Apr 06 '22 at 14:57
  • Thanks everyone for the quick help. – Dennis Cahalane Apr 06 '22 at 17:04

1 Answers1

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I recommend checking out the Sagulator.

You can use it to determine approximate load bearing capacity of almost any wood type for any span and weight. The Sagulator will report the expected deflection under a given load amount and type and will report whether it's considered acceptable or not. Of course, final judgement is up to you.

Do bear in mind that wood is a natural product and that no two boards will be exactly the same. I'd imagine that these are somewhat conservative numbers, but I haven't read all the fine print at their site to be sure of that.

You indicate 2" x 10" (or 12"). When plugging your numbers into the Sagulator, be sure to specify 1.5" by 9.5" or 11.25" if you're using standard dimensional framing lumber since that's sold as a "nominal" 2x10 or 2x12. You'll want the calculations to be based on actual lumber sizes.

FreeMan
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    Sagulator is nice except for its traffic light judgments. As you say ... conservative. The bar seems to be "imperceptible sag" which is often desirable but often unnecessary. – jay613 Apr 06 '22 at 15:07
  • I'll be certain to use the addressed down size of the wood. Thanks for the top. – Dennis Cahalane Apr 06 '22 at 17:05