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oilersfan
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# Posted: 5 Mar 2013 15:37
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Hello everyone!!
I can't seem to find much info on beam sizing for small cabin type structures...hoping someone can help me out.
I am planning the following...
- 12x16 shed type cabin
- beam sizing - 2x2x10 (plan on 3 piers spaced along the beam so approx beam span would be 8ft.)
- joist sizing - 2x10 @ 16"OC (don't plan on an intermediate beam so joist span is 12ft which I think is fine)
The framing book i have notes that single story structures require beams 3-2x6s and up depending on the span. I haven't come across many cabin structures that seem to have a built up beam with 3 pieces of lumber. I would also consider installing 1 more pier to cut down the span but I don't want to overdesign if I don't have to. Anyone??
Also I wouldn't mind setting the beam directly on top of the piers however almost everything I see has the pier, post, and beam install. Any advantages to installing the post other than not having to worry about the levelling as much?
Thanks in advance.
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Anonymous
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# Posted: 5 Mar 2013 21:01
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you can't plan that w/o knowing about amount of snow if any or if there is a loft and if the floors are lightly or heavily loaded like in a typical full time residence, with 8 foot spacing you need at least 3 2x10 or 2x12 for beams down the sides and you want to have as few joints from footing up to the beam, pier post beam is badder than using pier to beam,
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oilersfan
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# Posted: 5 Mar 2013 22:19
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- Snow load is 70psf...Canadian rockies.
- Only weekend rec use.
- Small loft on 1 end of the cabin (5ft out)
If I add an additional footing reducing the span in half to 4ft, what beam design would suffice? I would rather have an extra footing then have to put together a monster beam.
Does anyone know where I can find additional information on the beam design?
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DungeonX
Member
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# Posted: 6 Mar 2013 08:40 - Edited by: DungeonX
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I just built a 16'x24'' cabin on three rows of cribbing with 3 beams spanning the cribbing. this winter we have had more snow that in the past 10 years and at one point I had clost to 2-3 feet on top of my tin roof.
Any way my beams are 3 laminated 2x8s and 2 layers of 3/4" plywood, glued and nailed at each layer. they havent moved or bowed at all. The plywood really adds alot of strength. It creats a beam that is 6"X 7.5" 24 feet long and i have 3 under my cabin.
XpXpX X=2"x8" p= 3/4" plywood
Hope that helps
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oilersfan
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# Posted: 6 Mar 2013 11:37
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Thanks DungeonX. I know in reality that my small shack even with the snow load doesn't need 3-2x10s laminated together. Everything I read sounds like complete overkill for a cabin type structure. At the end of the day this is a small weekend cabin used once or twice a month so I am not going to stress too much but always nice to get a second opinion.
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Rob_O
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# Posted: 6 Mar 2013 12:32
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Here's a link to the IRC page on girders.
URL
Looking at the numbers for a 28' wide structure with a center beam (essentially a double-wide version of your build) you are right on the edge of code with your 2* (2x10) beams and another set of piers.
I'd say you are good to go
Quoting: oilersfan If I add an additional footing reducing the span in half to 4ft
Adding an additional pier will reduce the spacing between post centers to 5-4. Code says your beam will span 5-1 so as long as your pier is a x6 you are code-compliant
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toyota_mdt_tech
Member
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# Posted: 7 Mar 2013 00:36
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A 12 foot joist span, you can use a 2X8 at 16" OC
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Press
Member
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# Posted: 7 Mar 2013 19:44
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I am planning something similiar, 16 x 24' with loft, in VA, rarely more than 24" of snow here, on three rows of double 2 x 10 beams running the 24' with posts 8' apart, and was also wondering if that was enough posts.
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