Metal roof sheet queries?

[Ruggers]

View attachment 221297

It still looks solid few years left in it.

It's just a storage shed not a workshop so the sound inside it shouldn't bother me, its 3m away from the house. It's just making sure it looks ok and lasts a long time.
I knew many add ply underneath but didn't know if it stops the condensation problem or just means that it then happens between the metal sheet and the OSB instead causing the wood to rot?

Slates would match the house but as previously mentioned, it's pricey and if any get damaged with it being a single story height roof, they are harder to repair and i think the roof timbers will cost more being many at 400 centres.

 

[Harry Bloomfield]

I rest my case

Well, what else can you do? You have posted a photo of an old corrugated steel roof, with no clue as to how long it had been there, on a tumble down construction. I fail to see what it really proves.

What I can say is my now 10 year old modern box section corrugated roof on my 24 x12 garage plus an extra workshop area - is absolutely fine, not a hint of rust anywhere.

 

[Old Salt]

I haven't posted any pictures of old corrugated roofs.

 

[catlad]

That was different old crack pot!

 

[Ruggers]

Having looked at various metal roof sheets, is there any good brands that last longer or brands to avoid? I've came across one called master rib which seems good but possibly expensive. I've read loads on this and there doesn't seem to be any solid advice, everyones experience is different depending on their construction and dew point causing the condensation.

If i'm to use metal sheets, mine being an unheated storage shed won't have any additional heat, so i'm thinking of OSB board on rafters and then attaching the metal sheet direct to the OSB and into the rafters and fitting the foam eaves fillers.

Would it be worth covering the OSB in some membrane like visqueen, would there be a build up of condensation between the OSB & metal sheet?

 

[cdbe]

I had metal sheets on my lean-to garage roof, quite a nice looking tile effect, polyester coated. I insulated with 100mm loft roll between the rafters and underboarded with some 6mm mdf sheets (actually a load of ex bandq kitchen drawer bottoms I picked up cheap). Never any condensation in 3 years. Unfortunately I bought a caravan and had to jack up the outer edge of the roof by 6" to fit it through which made the pitch too flat and leaky so I stripped the roof, boarded it with 9mm OSB and covered with EPDM - an easy DIY job - the wet insulation was removed and still no condensation with just OSB and epdm, which I believe is air permeable.

 

[Ruggers]

I had metal sheets on my lean-to garage roof, quite a nice looking tile effect, polyester coated. I insulated with 100mm loft roll between the rafters and underboarded with some 6mm mdf sheets (actually a load of ex bandq kitchen drawer bottoms I picked up cheap). Never any condensation in 3 years. Unfortunately I bought a caravan and had to jack up the outer edge of the roof by 6" to fit it through which made the pitch too flat and leaky so I stripped the roof, boarded it with 9mm OSB and covered with EPDM - an easy DIY job - the wet insulation was removed and still no condensation with just OSB and epdm, which I believe is air permeable.

So you just attached the metal sheets to your rafters direct, then insulation between them with thin mdf backing attached to the inside of the rafters instead of adding the sheet and osb to the top of the rafters like most do? Why was the insulation wet?

EPDM over OSB is a good choice for simple roofs with less cuts and joints from what I've seen, but i was considering the option of adding solar thermal in the future and EPDM wouldn't be simple. Not sure how EPDM sits over a ridge on a dual pitched roof, is it tough stuff? would anything affect the ridge over time, seagulls etc.