Condensation on tin roof

[gumby6371]

I have a brick built shed with a tin roof at the bottom of my garden which suffers badly with condensation on the roof. There is plenty of ventilation as the ends of the sheets are open due to the corrugations and I can fit my hand through each of the gaps. Its so bad I have to cover everything with plastic sheeting in the colder months.
Its 4.5 metres by 3.5 metres and a rented property so I don't want to spend loads putting a decent roof on it but I've had a thought......

If I get some spray adhesive and stick polystyrene sheets to the underside of the corrugated steel would that stop the condensation forming???

The other half works next door to a furniture sales place so I can get plenty of polystyrene for free as they just bin the stuff and I've had it off them before for other jobs so it must be worth a try???

[Doggy]

Condensation will form on the coldest surface it can find. Unfortunately insulation will not prevent the surface becoming as cold, it will just take longer to lose heat, (but being thin sheet and uninsulated on the other side it won't make much difference).

Ventillation doesn't help if the 'fresh' air contains as much water vapour as that it's replacing. May actually make it worse.

[Welly]

Awkward one, you'll struggle to get a decent fix to those corrugations and then the condensation will continue to form above the poly sheets in the empty cavities of the corrugations, probably bring down the sheets over time. Insulation only works if you're trying to retain heat from a heat source, otherwise the whole lot will just stabilise to the same temp and make no difference.

Cheapest fix* would be to frig up a warty catcher layer; cheap ass timber batterns with thick poly sheeting stapled thereto and just-below the roofing sheets and the droplets will collect and run off to one side (hopefully outside). It won't be pretty.

[gumby6371]

I've already tried palstic sheet fixed to the rafters but condensation formed on the under side of the plastic.

Maybe I should just keep all my tools and stuff in the house, I'll see what the good lady says when I suggest a tool cupboard in the front room

[Welly]

What about gluing Laminate Floor Underlay directly to the steel, but following all the corrugations, someone on Google said it worked and the underlay is a vapour barrier as it's laminated with clear foil.

http://www.mig-welding.co.uk/forum/thre ... elp.23962/

[GingerMagic]

Can you lift up one side of the roof a tiny bit, maybe a couple of inches, so the water runs down to one side?