Metal shed roof condensation solutions?

[fha772]

Aye up,

I've been pondering this problem for a few weeks now.
The double deck artic trailer I've got for a shed has quite a serious condensation problem, with the single skin aluminium roof.
When I say a condensation problem, I mean a condensation problem!! In the winter, if I have to go into the top deck for something I have to put on my waterproofs!! everything up there is sheeted up.
During the summer there's no problem at all, it's just during the winter.

The only solution I can think of is to insulate and ply line the ceiling, using rock wool and really thin ply, which is going to be a right arse to do, seeing as it 45ft by 8ft.

So, I wondered if there was an easier solution to this problem, maybe something that could be painted on, that would stop the condensation forming on the roof.

Any ideas would be great, if there's nothing, then I'll get cracked on with the ply lining.

Cheers Frank.

[owelly]

A dehumidifier? Take the moisture out of the air so it can't condense into wetness....

[Relentless Rob]

Insulation would absorb the water turning it into a damp/rot problem instead. There is a coating you can apply that helps reduce it and dehumidifiers also help but with Aluminium especially I don't think there's a solution.

[fha772]

That's my problem, I only have power in the shed when I run a cable across the yard, I can't leave it on all the time, because it wouldn't last with lorries running over it.
So I need a solution that doesn't require a power supply.

[mjslonergan]

Small gennie outside...

[fha772]

Small gennie outside...

I've got a 195KVA silent running generator next to it, but that uses 25 gallons an hour...

[Renrut]

Do what my dad did for his cellar - dehumidifier. Power comes from solar panels on the roof charging a set of 12V batteries, the dehumidifier runs on a timer via one of them cheap 12V to 240V inverters.

The cellar used to be permanently damp, and the usual solution is tanking it but since setting it up like above its been fine, its like any other room of the house now.

I can get the details of all the bits but knowing him 90% came from a combination of Aldi, Lidl and Poundland - he's the electrical equivalent of a Womble.

[tooSavvy]

That's my problem, I only have power in the shed when I run a cable across the yard, I can't leave it on all the time, because it wouldn't last with lorries running over it.
So I need a solution that doesn't require a power supply.

Why not trench a pvc duct & cable it?

tooSavvy

[fha772]

The yard is solid concrete, and about 2-3 feet thick.

[andrewg1323]

You can get spray on insulation for buildings, looks like expanding foam, could be an option

[Chairchild]

sheets of polystyerene (wickes/etc) held in place with long nuts+bolts through theroof, and some "washers" (bits of plastic) to help spread the load.

Relatively cheap, and should last along time too

[Renrut]

TBH even a decent coat of paint would reduce the problem as its the relatively cold surface thats the issue.

[gary5687]

why not just fit some vents in the unit.... cause a draft and the condensation will go.....

[owelly]

Mount a couple of wonky fans on the roof. As the roof vibrates, the condensation can't stick to it!

[mjslonergan]

If you paint it with something matt, and if possible slightly textured, that should stop it, as condensation usually prefers shiny surfaces...