Timber Size for Shed Roof

chrisell
Posts: 161
Joined: Fri Mar 02, 2018 12:37 pm
Has thanked: 11 times
Been thanked: 39 times

Timber Size for Shed Roof

Post by chrisell » Tue Dec 24, 2019 10:37 am

Its not really a shed but an internal box

Thinking of creating a gym and game room in the barn. Can't be bothered learning about metal framing so sticking with old fashioned timber frame. Internally I'll clad it with OSB walls and ceiling - externally probably just wrap it in DPM and only bother facing off the bit you'll see - and that'll be either more OSB or some cheap timber.

It'll basically be a big box inside the barn - or a big shed- but the space is pretty big and I'm only doing this once so probably in the region of 6 metres by 8 metres split into two maybe 3 rooms - one big room and a smaller narrower space. I could arguably use the existing walls - but seems more sane to just build a box that can be insulated before I have to start installing heating.

I figure Chevron or Demi Chevron for the framing and roof - am I skimping at Demi Chevron? I've stuck enough internal walls up with demi chevrons but they were always small. I'm guessing roof will need to be at least Chevron just so it doesn't sag when I slap a ceiling in - or do I have to go to 6x2 given I'm probably looking at 4 metre spans regardless of whether I want the roof to take any weight.

If the roof were to be load bearing - I assume I'd need to go up quite a bit in timber size - 6 x 2 for the roof beams and at least some of the uprights? It may be useful to keep the roof for storage - or just to stick a small studio up there.

All internal - no windows - no fixed heating - no paper to faff with - just don't want to have to fix it in a few years. I'll build a floor more to level the existing floor than anything else - but it'll sit on the existing rough timber and obviously use the joists of the barn to take the weight. I was hoping to just go Chevrons for the floor with yet more OSB

User avatar
just a Frenchie
Posts: 1910
Joined: Thu Sep 26, 2019 2:19 pm
Location: Vendée
Has thanked: 863 times
Been thanked: 581 times

Re: Timber Size for Shed Roof

Post by just a Frenchie » Tue Dec 24, 2019 11:30 am

I've found that for you:
http://charpente-total-bricoleurs.wifeo ... sibles.php
4 meters span... IMO, you will need more than chevrons unless you can have beams underneath to divide the length.
You learn from your mistakes but it's much quicker and cheaper to learn from the mistakes of other people ! :D

User avatar
Fitter
Posts: 2184
Joined: Thu Mar 01, 2018 7:17 pm
Location: Brittany 56
Has thanked: 46 times
Been thanked: 501 times

Re: Timber Size for Shed Roof

Post by Fitter » Tue Dec 24, 2019 11:36 am

Been there - done that! My workshop and store room inside big old cranky tin and timber barn.

it's 3.9 m x 7.5 m outside. The timber was 95 x 44 cls treated. Cladding is 11 mm osb double skin with rockwool between the skins.
The roof is 95 x 44 rafters at 600 centres. I tested these before building the roof by loading them for a week on the floor with concrete blocks over the length of the span and measured the deflection according to the load of the rafters+ osb + the rockwool in the roof = negligable deflection.

I've loads more pics if I can find them.
IMG_0168.JPG
IMG_0168.JPG
IMG_0171.JPG
IMG_0170.JPG
IMG_0169.JPG
IMG_0168.JPG
Attachments
PICT0034.JPG
“He who controls the past, controls the future; and he who controls the present, controls the past.”
George Orwell “1984”

User avatar
Fitter
Posts: 2184
Joined: Thu Mar 01, 2018 7:17 pm
Location: Brittany 56
Has thanked: 46 times
Been thanked: 501 times

Re: Timber Size for Shed Roof

Post by Fitter » Tue Dec 24, 2019 12:25 pm

You don't say what sort of barn you have - timber or stone etc.
A tip if it's timber like mine - don't build it supported or joined structurally to the barn timbers, wooden barns wriggle around in the wind and with temperature changes. I made my workshop an independent structure bolted to the concrete floor and any covering joins to the barn structure were made with sliding overlapping joints.
“He who controls the past, controls the future; and he who controls the present, controls the past.”
George Orwell “1984”

User avatar
Aardvark
Posts: 2692
Joined: Fri Mar 02, 2018 4:08 pm
Location: 22
Has thanked: 2262 times
Been thanked: 727 times

Re: Timber Size for Shed Roof

Post by Aardvark » Tue Dec 24, 2019 12:45 pm

I'd give a kidney for a barn half that size.
R.I.P. UK

User avatar
Fitter
Posts: 2184
Joined: Thu Mar 01, 2018 7:17 pm
Location: Brittany 56
Has thanked: 46 times
Been thanked: 501 times

Re: Timber Size for Shed Roof

Post by Fitter » Tue Dec 24, 2019 3:19 pm

Aardvark wrote:
Tue Dec 24, 2019 12:45 pm
I'd give a kidney for a barn half that size.
Half that size would be about 50 feet x 20 feet inside! And there's another 14 foot cantilever overhang outside covering where the original sawmill machinery was, long gone before we bought it unfortunately.
It's a bit of a mixed blessing is the big barn - it's a bit like the forth bridge for maintenance - you think you've finished for a month or two and then a wriggly tin sheet comes loose in a gale and then your're up on the roof again!
“He who controls the past, controls the future; and he who controls the present, controls the past.”
George Orwell “1984”

chrisell
Posts: 161
Joined: Fri Mar 02, 2018 12:37 pm
Has thanked: 11 times
Been thanked: 39 times

Re: Timber Size for Shed Roof

Post by chrisell » Tue Dec 24, 2019 6:49 pm

Fitter wrote:
Tue Dec 24, 2019 12:25 pm
You don't say what sort of barn you have - timber or stone etc.
A tip if it's timber like mine - don't build it supported or joined structurally to the barn timbers, wooden barns wriggle around in the wind and with temperature changes. I made my workshop an independent structure bolted to the concrete floor and any covering joins to the barn structure were made with sliding overlapping joints.
Stone barn with wooden beams/floors. Its ground floor on one side and 1st floor on the other side. The plan was completely separate from the walls - literally a freestanding box - I was pondering whether to just build it "floating" and level up "inside" on something approaching true with the worst bits just packed out well or fix and level to the wooden floor. My idea of level isn't exact mind - I'm good at level'ish and straightish and really good at that'll be fine.

chrisell
Posts: 161
Joined: Fri Mar 02, 2018 12:37 pm
Has thanked: 11 times
Been thanked: 39 times

Re: Timber Size for Shed Roof

Post by chrisell » Tue Dec 24, 2019 6:54 pm

Aardvark wrote:
Tue Dec 24, 2019 12:45 pm
I'd give a kidney for a barn half that size.
And then you just fill it with tat. If I don't do something useful with the various bits of barns/building I've got they'll just end up full of crap I don't need.

chrisell
Posts: 161
Joined: Fri Mar 02, 2018 12:37 pm
Has thanked: 11 times
Been thanked: 39 times

Re: Timber Size for Shed Roof

Post by chrisell » Tue Dec 24, 2019 6:57 pm

Fitter wrote:
Tue Dec 24, 2019 11:36 am
Been there - done that! My workshop and store room inside big old cranky tin and timber barn.

it's 3.9 m x 7.5 m outside. The timber was 95 x 44 cls treated. Cladding is 11 mm osb double skin with rockwool between the skins.
The roof is 95 x 44 rafters at 600 centres. I tested these before building the roof by loading them for a week on the floor with concrete blocks over the length of the span and measured the deflection according to the load of the rafters+ osb + the rockwool in the roof = negligable deflection.
That'll take an earthquake.

User avatar
Aardvark
Posts: 2692
Joined: Fri Mar 02, 2018 4:08 pm
Location: 22
Has thanked: 2262 times
Been thanked: 727 times

Re: Timber Size for Shed Roof

Post by Aardvark » Tue Dec 24, 2019 7:24 pm

chrisell wrote:
Tue Dec 24, 2019 6:54 pm
Aardvark wrote:
Tue Dec 24, 2019 12:45 pm
I'd give a kidney for a barn half that size.
And then you just fill it with tat. If I don't do something useful with the various bits of barns/building I've got they'll just end up full of crap I don't need.
Maybe so but I'd still enjoy being able to work on something without having to bring it into the house or wait for a non-rainy day to do it outside. I have a workshop about the size of most people's bathroom. With the compressor, welder, sawbench, pillar drill, grinding wheel, polishing wheel, 2 rolling tool cabinets and a rack of powered hand tools there's no room left to do anything. :?
R.I.P. UK

Post Reply