Jameshow
Established Member
Why not use 18mm plywood with 3x2 lapped framework.
Put it ply on outside temporarily and then reverse and clad on the outside.
Shed build, many many questions...
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Put it ply on outside temporarily and then reverse and clad on the outside.
Nope I did not, I just brought the epdm around the side of the roof and pinned underneath with a small Barton to act as a drip edge. The trims were expensive I thought and served little purpose as there is no guttering on my shed so no issue where the run off happens.
I think it is local usage- here in Australia metal roofs are the standard for sheds (and since the 1970's houses as well)Side question:
Can anyone explain (in laymans terms), why felt / rubber etc., are suitable for low pitch roofing but (seemingly impermeable) sheet steel is not? I can't quite get my head around this, I must be missing something obvious - wind?
Especially colourbond (powdercoated) sheeting- my entire shed is made of it- 35 year guarantee- on the powdercoat not coming off or discolouring... the roof itself will outlast me by a considerable margin...
Leaks are practically unheard off (usually only after a cyclone or something damages the roof beforehand)- I have seen US manufacturers saying they put the screws in the valley- so relying on the rubber washers to do sealing- where ours here are the exact opposite- that voids the warranty for leakage- as they say to put them on the 'tops' of the ridges- so unless your rain is of 'Noah's loading the ark' levels, then the possibility of leakage is next to none- the entire 'gully' has to be filled up to the level of the ridges- even on a flat roof thats unlikely... (and the rubber seal on the screw has to have deteriorated as well)
As for wind, my shed is cyclonic rated, and i know from experience they hold up extremely well to cyclones, A shed from the same company survived with no damage at all, unlike the house (old fibro farm house) that needed quite a few sheets on the walls replacing (its metal roof was fine however)
Metal roofing is by far the best option imho
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Molynoox
Established Member
That's interesting. Makes total sense fixing it on the peaks.
What about the condensate issue, is that not a problem in Australia?
Martin
We don't worry about it for most sheds, but houses use a combination fiber insulation/silver sarking sheet under the roof itself- mine I had it installed as this will be a working shed, and we get 40C plus temps in summer- so insulation stops the worst of that
That's the 'backside' of the triangular wall in the first pic, taken inside the main shed, the first was a 'leanto' that will eventually be my machining workshop proper
clogs
just can't decide
I've built steel sheds n workshops all over the world.....
Here in Crete the go to sheeting is double skinned steel with 40mm of high density foam....
It is self supporting at 3m between joist and thats exactly what I use for my caravan and new shed build....plus on my caravan roof there is a solar water system and I reg walk over said roof it to inspect it....on the new shed (160m2) I will use an extra purlin, thats for the photo elec cells, (were going off grid) reason for the extra support is the high winds we get in winter not the weight.....
no condensation or leaks......
had a steel scaffold pole hit the roof in a maj storm it ripped the outer skin but still no leaks..........
Cant understand why people use felt or wood.....as steel is the same price or better.....
fast, easy contsruction methods for a shed /mini barn is a steel frame, with walls n roof with the above steel sheeting...u can specify quite a few colours now......plenty of used roofing in the UK...Oh, u lucky people....
done correctly all the framing is bolted together, welding and cutting is on the floor.....
pour the pad set the studs and with 2 guys it can be water tight in a weekend....
PLUS u can take it down if u need too (moving) or to add on an extra room....
Also u dont need heavy girders providing u frame properly......
I use 150x50x 3mm thick hollow box.....any small welding firm will cut and weld the gussets.....galv is nice but paint will suffice.....
this is 7.5mx7mx 4mH...and no the front legs are not drunk....hahaha....
a mate and myself assembled this in a weekend...just a temp cover for the crates....quite a bit more steel will be used in the final shed....
spent a week making the frame (welding and drilling).....it's now double this size....
caravan cover is 11mx7.5mx3.5m.....notice a steel box frame for the terrace....cheap...
those roofing sheets are just a 1m covering (wide) and 2 of us can man handle a 7.5m length.....they make a special shaped washer for the fixing screws.....
(NOTE, fixings on the ridges of the sheet not the valleys.....)
I did use my forklift to get em up there tho....
but a little shed, they can be carried easily and even down the side of the house....along with the frame.....simples.......
the roof pitch is 5 deg on mine as we never get snow....at least 10deg min but 15 is ideal for UK......
when finished they will get hand made HD guttering for the monsoon rains in winter....
I did make the storage shed to use an extra 3 legs but to get the crates in it was easyer to leave them off.....that has stood for 3 years now....
note, the 1 ton bags of stone to hold it down.....hahaha...
good luck...
ps, the wood for the decking, 7mx4m was almost €800 three years ago....
here gazebo's etc are now made from steel.....wood is just mental money.....
5mLx150x 50mm joist, rough sawn c@rp was over €40 each 2 years ago....now.....??????
Here in Crete the go to sheeting is double skinned steel with 40mm of high density foam....
It is self supporting at 3m between joist and thats exactly what I use for my caravan and new shed build....plus on my caravan roof there is a solar water system and I reg walk over said roof it to inspect it....on the new shed (160m2) I will use an extra purlin, thats for the photo elec cells, (were going off grid) reason for the extra support is the high winds we get in winter not the weight.....
no condensation or leaks......
had a steel scaffold pole hit the roof in a maj storm it ripped the outer skin but still no leaks..........
Cant understand why people use felt or wood.....as steel is the same price or better.....
fast, easy contsruction methods for a shed /mini barn is a steel frame, with walls n roof with the above steel sheeting...u can specify quite a few colours now......plenty of used roofing in the UK...Oh, u lucky people....
done correctly all the framing is bolted together, welding and cutting is on the floor.....
pour the pad set the studs and with 2 guys it can be water tight in a weekend....
PLUS u can take it down if u need too (moving) or to add on an extra room....
Also u dont need heavy girders providing u frame properly......
I use 150x50x 3mm thick hollow box.....any small welding firm will cut and weld the gussets.....galv is nice but paint will suffice.....
this is 7.5mx7mx 4mH...and no the front legs are not drunk....hahaha....
a mate and myself assembled this in a weekend...just a temp cover for the crates....quite a bit more steel will be used in the final shed....
spent a week making the frame (welding and drilling).....it's now double this size....
caravan cover is 11mx7.5mx3.5m.....notice a steel box frame for the terrace....cheap...
those roofing sheets are just a 1m covering (wide) and 2 of us can man handle a 7.5m length.....they make a special shaped washer for the fixing screws.....
(NOTE, fixings on the ridges of the sheet not the valleys.....)
I did use my forklift to get em up there tho....
but a little shed, they can be carried easily and even down the side of the house....along with the frame.....simples.......
the roof pitch is 5 deg on mine as we never get snow....at least 10deg min but 15 is ideal for UK......
when finished they will get hand made HD guttering for the monsoon rains in winter....
I did make the storage shed to use an extra 3 legs but to get the crates in it was easyer to leave them off.....that has stood for 3 years now....
note, the 1 ton bags of stone to hold it down.....hahaha...
good luck...
ps, the wood for the decking, 7mx4m was almost €800 three years ago....
here gazebo's etc are now made from steel.....wood is just mental money.....
5mLx150x 50mm joist, rough sawn c@rp was over €40 each 2 years ago....now.....??????
I like everything about the stuff, but I just can't get the manufacturer's recommended pitch, without losing significant head room.
Roof design for comments please 
I can do this with 6 x sheets shown in blue. Not sure if the perimeter beam is necessary or even adds weight I could do without? Otherwise I'd probably just use a thicker UPVC facia or maybe do something with the cladding.
No noggins needed as it's under 2.4m span. 5" x 2" beams as suggested.
Thanks for all the advice so far, I feel like I'm almost ready to start doing something again without the anxiety of doing something wrong I'd have to undo...
I can do this with 6 x sheets shown in blue. Not sure if the perimeter beam is necessary or even adds weight I could do without? Otherwise I'd probably just use a thicker UPVC facia or maybe do something with the cladding.
No noggins needed as it's under 2.4m span. 5" x 2" beams as suggested.
Thanks for all the advice so far, I feel like I'm almost ready to start doing something again without the anxiety of doing something wrong I'd have to undo...
Jameshow
Established Member
Thier recommended pitch will be for industrial building your shed will be fine.I like everything about the stuff, but I just can't get the manufacturer's recommended pitch, without losing significant head room.
A 4" over 8' gradient will be fine.
I think it’s more like 3”, I’m tempted but I’d rather be 100% sure… I’ve mostly settled on EPDM now, I’m just curious.
Inspector
Nyuck, Nyuck, Nyuck!
Treated wood is normally for wet, ground contact or termite problems. If you are making it to be dry why would you want treated wood? Houses I helped build out of high school in the mid seventies are still standing with no issues. I could see using a treated sill but not beyond that. If you feel there is a need for treated framing then the sheathing should also be treated stock.
Pete
There doesn’t seem to be a lot of difference in cost (online anyway, haven’t asked over the counter yet and sometimes the prices change). Approx £1 per length difference, so £50/60 more to use treated timber throughout.
Molynoox
Established Member
I wouldn't want to contradict Pete, but I think there may be some value in using treated wood. The reason I feel that way is because sheds and garden rooms are not built like houses, not subject to building control etc. So they are often not vented and sometimes not sealed properly. You do tend to hear of more issues with condensation and moisture for garden buildings than with houses. That's all a bit anecdotal and might not be true but I would say there is a case to be made for treated especially as the additional cost is so minimal. I'm not advocating over engineering but for me when I did the cost / risk balance it swung in favour of using treated. But it's a good point about the OSB not being treated and hence perhaps the weakest link.... Although I think OSB3, which most people use, does have a level of resilience designed into it that makes it suitable for outdoor environments?
Martin
Martin
Inspector
Nyuck, Nyuck, Nyuck!
Our 2x4x8' studs are $6Cad. The treated ones (not ground contact rated) are $9Cad. That makes building with treated 50% more and that doesn't factor in the corrosion resistant fasteners you have to use for treated lumber.
I won't loose any sleep if you contradict me. It's okay.
Pete
I won't loose any sleep if you contradict me. It's okay.
Pete
Terry - Somerset
Established Member
There are a variety off different building practices around Europe - I'm not sure whether this is a simple consequence of historical familiarity, or something more fundamental leading to development along different tracks. The main variables may be:
- climate - the Med is typically very different to the UK - warmer, more sunshine, less rain. Other bits of Europe may have more snow, greater seasonal temperature variation. Compare Alpine to "Costa" type design and structures.
- local material availability - may be a historical legacy despite improved transport capability. UK had very distinct regional differences - eg: roof using thatch, slate, tile, etc.
- longevity - UK aspires to a long design life of 100+ years with limited major repairs.. In other parts of the world no more than a couple of decades seems acceptable. Some Gulf states commonly replace buildings less that 15 years old as the existing no longer meet the need.
Treated timber will be treated against fungal decay and insects. It would be difficult and expensive to replace at a later date so you should use treated. For non structural parts which can be easily replaced or may be modified untreated is ok.
You’re dead right about this (not that I had any doubt), I went camping in Wales for a few days and it’s used all over at very low pitches
