A shed will have roofing felt applied, so it will need to support the weight of one human to do that. The roof planks are 1.6 metres long, how thick should the be to support (let's say) 90kg of human?
- posted
10 years ago
A shed will have roofing felt applied, so it will need to support the weight of one human to do that. The roof planks are 1.6 metres long, how thick should the be to support (let's say) 90kg of human?
3x2 should be plenty... (depends a bit on how far you have them spaced)
Peter Percival scribbled...
You can support the roof when you're working on it with an acro or some lengths of 3x2 wedged with boards under the roof timbers. No point in over building a shed when you're not going up there again.
Until you have to refelt it. But it doesn't take much to support somebody. Of course if you make the roof stronger for that it also makes it stronger for hanging things from :-)
Wind and snow loadings are the main factor.
The pitch of the roof will also affect its load bearing capacity. If you are worried it may be too light then increase the purlins in thickness or number and put diagonal bracing in the end bays.
I would think if that is the only issue you could get away with a single
2x1.Of course it isn't the only issue...
Clive George scribbled...
I dread to think what you get up to in your shed.
harryagain scribbled...
Did I miss the part about building this shed in the Artic ?
You obviously missed last Winter here, then.
On Thursday 25 July 2013 09:34 The Natural Philosopher wrote in uk.d-i-y:
Indeed. Oversizing the timbers will make screwing a lot easier (remember, crappy flat pack sheds are nailed and stapled together).
A self drilling screw will have no trouble holding and not splitting 2x2,
2x3 or 2x4. 1x2 however would be nightmare to work with IME.
Designing a structure, any structure, to resist wind loading is very import ant even in this country. ISTR snow loading has to be able to account for the dreaded 150 year loading. (i.e.) The worst possible case. I've seen ent ire commercially built chicken sheds take off in high wind and they weren't particularly exposed. Some years back a local bus company while building a bus garage had a wall blown down on them before they could brace it proper ly.
obvious seasonal error corrected
that sounds like poor design as the walls should be self supporting, how else will they stay up with the roof adding more loads.
Yes it was bad design or bad building practice. The walls were very tall.
Not sure what you mean by roof planks, if you mean the horizontal running planks, length is unimportant, its section & span of rafter underneath is key. Assume you are buying C16 grade timber ...
at 400 c/s a 38x97 will be good for up to 1.92m span that assumes you are having a flat roof (slight slope)
or if you want to do 600 c/s a 44x97 will be good for 1.79m
If it's a pitched roof between 10 and 22 degrees at 400c/s a 38 x97 is good for 2.11m (44 x 100 gives you 2.36m)
or if you want to do 600 c/s a 38x97 will be good 1.94m
5 degrees maybe.
The roof slopes by about 5 degrees. The distance between the walls is
1.6 metres. The planks will be laid across the walls, with no other support. I have some planks that are 47 mm thick, so I'm wondering if I can use them and buy more of the same thickness. The planks go across the slope not down it.Excuse my ignorance, but c/s means nothing to me.
Did you mean to call yourself after cold northern climes, or was that a typo?
Andy
Guess c/s means centre spacing (i.e. distance apart). Shed I built has a roof span of ~3m, pitch 10-20 degrees and I used 2x3s C16s prob about
45-60cm apart. Took my weight when roofing without any issues (I was always supported by boards across multiple rafters though.)I'm guessing you're proposing completely boarding the roof with the planks. At 2" thick and ~5' span I'd guess you should be just fine assuming you fix the planks down before getting on them. And assuming they aren't rotten!
(The flat-pack shed I bought had an incredibly flimsy roof, and took my very large mate's weight when felting. I wasn't prepared to get up there given how flimsy it was!)
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