Have a double garage which is concrete sectional and has a congregated roof. A few weeks back i decided in my wisdom to plug the little gaps between the roof and the walls with a little loft insulation. Hoping this would cut down drafts etc.... I'm a warm weather tinkera!

The garage only gets opened once or twice per week as its not at my house.

I noticed on Friday that my big metal tool box was slightly damp on the surface with condensation. The garage roof does not leak.

Thinking about it i have probably caused the issue by not allowing the garage to "Breathe".

Am I barking up the right tree?

If so what are my options:

Remove the insulation
or
Fit some vents
Extractor fan

Open to ideas.

- Ash

It does look that way, so I would remove some of the insulation, plus as its not that cold yet, anyway

Condensation in house lofts is often caused by blocking vents in the eave so unblock the garage roof and build a sub roof and insulate that
So air still flows under the corrugated

My 'tin' roof is boarded out with insulation in the gap but I also have an extractor fan on a timer. It comes on for 15mins every 2hrs and seems to keep it all nice and dry

Am extractor fan would waste more energy than the insulation would save. A garage isn't like a house, there are fewer sources of damp so they need less ventilation. There's no one breathing, having showers, drying clothes etc. Id leave the insulation in so there are no drafts when you're in there, but have a vent to keep it aired when you aren't there.

quote:

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Originally posted by snapper
Condensation in house lofts is often caused by blocking vents in the eave so unblock the garage roof and build a sub roof and insulate that
So air still flows under the corrugated

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We park our snow covered cars in a two car garage which is not heated except for what leaks from the back wall of the house and the bedrooms above.

Once the winter has settled in like now -24 c last night, the garage gets very damp. The garage is at +4 C right now.

We use a de-humidifier which handles the job quite well, takes about a gallon of water out of the air in a week.

Plus we squeegee the floor at the same time we empty the de-humidifier.

I have the same type of garage with no insulation and loads of drafts and it still has huge condensation problems. It's just what happens when you have warm moist air blowing into a garage full of cold metal objects from the nights chill. No amount of ventilation will help that, you just have to make sure you keep the whole lot above the dew point.

Sorry about not replying... that thing called Christmas got in the way!

I can never remember the garage having condensation in the past, but i never really used it that much.

I'm only there at weekends so most of the time there is no ventilation from open doors etc.

There are two main areas that have been blocked - under the eaves and where the two roof panels meet in the middle.

I think the simplest solution is to remove the insulation in the top of the roof and see if the issue gets better.

I have thought about a small delonghi storage heater, but given its a double garage i did not think it would have any effect. I don't mind paying for the electric if its going to help the problem.

I have just purchased a hydro meter off fleabay so i can keep and eye on the problem and accurately measure it and see what changes make the most difference.

Thanks

Ash