roof condensation :-(

UKworkshop.co.uk

Help Support UKworkshop.co.uk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

cockney

Member
Joined
20 Aug 2012
Messages
6
Reaction score
0
Location
scunthorpe
Hi i wounder if anyone can give me some advice plese. i have built a large shed but i put a tin roof on it :( which is causing a massive problem with condensation dripping from it. can any one recommend a cure for this. some people say stick siver foil bubble wrap to the roof. if anyone has had this problem in the pass and has been able to sort it i would like to to here from you thanks Tom
 
I got some spray foam for my garage roof. It was 200 quid if memory serves. It made a hellish mess to apply, but fixed the problem. I still get condensation on the steel cross beams, so need to apply some more. But on the covered panels, it worked a treat.
 
Hi yes some people say that work great,but as you say it makes a mess and my shed is full of stuff so i was hope to try something different hopefully but thanks for your replay
 
You could always do it in stages? The mess is from where it drops straight down, unlike e.g. dust that spreads everywhere. So you could do it half/quarter at a time
 
You need to either keep the hot moist air away from the cold metal or don't have hot moist air. Using silver foil bubble wrap without some kind of seal and you'll still have the risk of condensation if the warm air reaches the roof, possibly with water pooling on the back of the insulation blanket. I see this is one of my outhouses, where polystyrene is shoved between the rafters, in the real cold I get ice buildup behind the insulation that thaws and drips out at random points when the weather warms up. The spray foam works well as it bonds to the tin preventing contact with the moist air. In my current shed I keep the air cold and me warm with layers, this way the air can't transport the moisture to the cold roof.

F.
 
Can you fix up insulation sheets in between the rafters? It's how I sorted my workshop but it was luck the beams were space nearly bang on 1200mm. Any small gaps then can be filled with squeezy foam.
 
hi yes i was thinking of putting up 8x4 sheets x2" thick and i got a 4" roof void would i need a air gap or would they need to be up to the tin roof ? thanks

as for the spring im not sure and also there is the cost to it as well WHAT TO DO LOL
 
cockney":111dome3 said:
hi yes i was thinking of putting up 8x4 sheets x2" thick and i got a 4" roof void would i need a air gap or would they need to be up to the tin roof ? thanks

as for the spring im not sure and also there is the cost to it as well WHAT TO DO LOL

I put mine up to the tin. Seems to work OK
 
I do the same as Fitzroy ..
Anytime its getting warm in there I open the door and let the moist air out
 
Interesting. Mine's damp all winter, whether I'm in there or not. And when I am working in there, the door is wide open.

F*** you, winter.
 
Maybe you need a drain ...any signs of rising damp on the walls, say some line 2 feet up ?
How high from the rest of the ground is it ...
Air circulation might help too... another small inlet should provide good enough draft...
When your in there, do you have a heater on ...and close the door afterwards ...might be a good idea to turn it off a bit before your finished .
Don't let the hot air in on summer days ..extract at night .
That's about the best budget solution I can provide .
Good luck
 
My garage/workshop was just the same - pre-fab concrete construction with a single sloped roof. It's a low ceiling height and it always gets pretty damp in there. And it used to cook in the summer too (dark brown roof!).

We had a new roof fitted professionally, but left the old one in place underneath it. There's about 3" between them, and some insulation. The new roof is made of commercial coil-coated panels, and unlike the original, it's strong enough to walk on, because it's thicker material, with deeper corrugations, and there are strengthening "purlins" underneath it too, on top of the old roof, bearing onto the lightweight steel beams supporting the original structure (which were easily strong enough for all this).

It has stopped "rain" from the inside of the roof completely, but not condensation, because I haven't successfully insulated the concrete slab walls and there is no DPC either.

It's worst in the late autumn and early winter. If we have a run of cold weather, the air dries (Ttrees mentioned this above), and if you then heat it, it can be quite snug, warm and dry (well, not horrid anyway).

We're considering moving house, but if we stay, I may have a go at insulating the walls, which would make a huge difference, but it'll have to be some sort of studwork.

To be honest the best thing would be to carefully dismantle it, keep the roof and rebuild the thing using blocks, on the same or very similar footprint.

It's not a solution for this winter, but if/when you can, I'd strongly recommend putting a second roof over the first one as we did. I didn't have to clear out the garage to do it either :)

E.
 
The difficulty with corrugsted tin roofs is preventing the condensation.

You can either convert it to a warm roof by spraying foam on it. That means there is no air gap anywhere for moist air to reach the cold metal.

Or you can leave a small gap and create a ceiling which must be continuous and contain a vapour barrier to stop any moisture getting through. The foil on celetex is an effective vapour control layer if all joints are taped. Any awkward gaps can be filled with expanding builders foam.
 
I had the same problem in my container which obviously is all steel. Basically just insulate against the roof with either kingspan/celotex/cavity wall slab whatever and fill any little gaps with expanding foam. Then completely cover with a plastic membrane and I'd use 11mm osb to finish. This prevents warm most air getting to the cold roof and the problem should be solved.

Sent from my SM-G935F using Tapatalk
 
Back
Top