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We have a en-bloc garage at the foot of our garden. Concrete segment walls with a cement bonded asbestos roof.
During winter, or for that matter anytime from October to April, the garage can suffer from a build up of condensation.
Every effort has been made to increase ventilation but the build up still occurs.
This year there will be a need to store bikes in there.
Previously a had thrown an old duvet over them followed by a tarp. This works but I believe there are better solutions!
Replacing the roof would help but from a VFM perspective its doesn't fly as will be circa £1000 and of the garages that have had this done they still suffer from condensation.
So my thinking ..... maybe a wooden structure in the garage?
Am I mad?
Other suggestions? I had thought of using a tarp as a second skin to the roof creating a 4in void between the current roof and the tarp.
I have the same issues with a breeze block/corrugated iron roof garage so I'll be interested to hear suggestions.
FWIW, my bikes have lived there for the last 7 years and other than cheap bolts, nothing actually seems to corrode.
I have a shed made the same way and don't have any problems with condensation. Is there any electrical equipment in there like a freezer or tumbly dryer?
Trail_rat posted this (asbesto roof thread) & I've seen similar comments previously:
what ever you do stick on the roof i suggest insulating the underside with airgap + kingspan or similar - stops condenation forming
I do wonder though (As I'm in the same situation), as there must still be condensation, but it'll be in the airgap & so the kingspan will eventually end up soaked?
Why would a shed help? The air inside's still the same air.
Polystyrene sheets battoned to the ceiling should do it. You could do the walls and line them with plasterboard or ply too.
Could you insulate the outside ?
I have just built a garage sized shed out of blocks and I was going to clad it in wood.
This was going to be more for looks than insulation,but you have me thinking now 🙂
No electric supply to the garage.
Had there have been I would have added a low powered extractor fan or such like to help (not sure it would have though)
Some sort of celotex/kingspan may help as its moisture retardant but as you say TR I'm sure the condensation would just build up in the void.
even if the condensation does build up in the void - where comes the issue ? - this is no different to the condensation that would be there anyway ....
i dont get deluged with condensation each time knock the kingspan so i assume its not staying long
but my tools and bikes are staying dry so i am happy. - this includes even in winter when i have my bombola heating the garage. - only place i get condensation now is on the thin metal door.
@molgrips ... my thinking was that my actual shed doesn't suffere a built up. and so some sort of internal structure may help keep a constant heat within it. It would also help cut don on the condensation drips.
fasthaggis ... No option to I'm afraid as its in effect mid terrace 🙂
@trailrat .... interesting. What thickness did you use? How did you fix it?
its not damp air in the room as such . its the fact that warm air has moisture in it .... the air in the garage is kept warmer than the air outside it - the garage roof isnt a very good insulator - so the air touching the garage roof quickly reaches dew point - so forms the water on the roof - which then soaks everything when the roof vibrates.
The actual AIR doesnt cause the corrosion its the water forming on the roof.
much like why you get water forming on the inside of single glazed windows.
Sprinkle rice all over the floor.
i have 50mm on my roof - i have a 6m x 3m workshop and a 3m by 2m garage that i use for storage and to line both roofs cost me 160 quid delivered to the door
I would have used plain old polystyrene if im honest but i was advised from a friend who has used polystyrene that it continually rains white balls all over his garage and does his head in 😀
to fix it - i used a nail in each corner - with the king span just resting down on them - then any gaps were expando foamed.
Big bag of salt or the like?
Otherwise what about a paraffin greenhouse heater?
So are you going use the parafin heater to warm the air on the outside of the roof then to stop the roof being the dew point ?
Check its condensation and not the asbestos sheeting itself thats gone porous.
A pricier much quicker/more effective option is the spray foam insulation they apply to warehouse roofs etc. Comes in gas bottles with an applicator/mixing gun and you would just spray it directly onto the roof sheets. No air gap between celotex and roof = no condensation.
Sometimes cheaper to pay someone to do it from bulk heated tanks in a van rather than the DIY method using bottles as you get more foam.