Metal shed roof condensation solutions?

[majic79]

it'll be condensing because the ally-skin is cold and the wet air is warm. Reduce the flow of wet air by removing air flow from lower compartment to upper - warm air rising from the lower compartment will condense on the cold alloy skin on the upper level, you'll need to improve ventilation in the lower level to do this. The other thing you might think of doing is double skinning with and putting insulation between the two layers (e.g. expanded polystyrene, expanding foam from the builders, etc, etc) and you can do that on the outside....

[Scrappyloz]

It happens a lot on series Land rover roofs. The way to get around it is to glue large carpet tiles on the inside of the roof

[Renrut]

...So, I wondered if there was an easier solution to this problem...

...put on my waterproofs!!

Fixed that for ya

[Evodelta]

Condensation occurs when warmer humid air hits a cold surface, two things you have to do:

1. Prevent most of this happening by insulating.

2. Ventilate the gap between insulation and outer surface to dry the surface for the bit that gets passed the insulation.

How you do it:

Construct a 'drop ceiling' with timbers, a boarded surface underneath (plasterboard will do) and insulation in between the timbers and over the top.

The space above this and below your roof surface needs to be 25mm min (50mm to be safe) and ventilated, - drill some holes in the outer walls with a rain shield over them.

The insulation can be the expensive 'Kingspan' type which has twice (per equivalent thickness) the insulating properties of glasswool which is much cheaper and at the moment government funded up to certain large percentages. Unless this has changed recently you just rock up to your builders merchant, fill in a form with your HOME details, say you're insulating the loft and off you go......

[Max]

Frank,

I was talking to the engineer where I work about a similar issue we have in the warehouse which is an insulated fridge inside a metal shed and we get 'rain' from the inside of the metal onto the top of the fridge which then freezes in the winter.

The solution is to thoroughly ventilate...

So, you need a false ceiling above which you have a couple of extractor fans that keep the air and moisture moving. The problem you have though is the limited height of your top deck (we have double deckers here so I know you've only got about 1.8 metres tops)

Could you put an additional roof on the trailer?

In my old garage I sheeted the roof in 3mm ply, covered the lot in plastic damp proof membrane and then put metal profile sheets over the top - never felt a drip in 3 years

[mjslonergan]

Turn it into a feature
http://www.google.ie/search?q=indoor+wa ... 21&bih=652

[ACE]

What do you use for heating?
Gas heater?
Diesel/paraffin/gas space heater?
All of these kick out vast amounts of water vapor, if you use one of these bin it and use electric, not a solution but should improve things. A lot!

Tried silica gel?