Insulating my garage

[nick60]

Hi all, I have a brick built single garage with flat roof attached to my house and accessible via a connecting door. I'd like to partition it and convert 2/3 of it into a space where I can store bikes, bike gear and my turbo trainer. I don't want to heat this space, I just want to make it look pretty and to stop it from having the full temperature variations of outdoors (which it currently does). Thinking of battening out the walls and putting on 40-50mm of Kingspan/Celotex, plasterboard and skim. Likewise the ceiling but probably 100mm of insulation between the joists. Also, 50mm Celotex on the floor, covered with T&G chipboard flooring and rubber matting. What could possibly go wrong?!!

I might want to dry kit in there as well, possibly using an electrically heated airer. To handle this I was thinking of a simple extractor fan to the outside plus an inlet vent somewhere. Any thoughts folks? Thanks in advance
Nick

 

[big-all]

with no heat input it will average the outside temperature after a few days
so if it averages 0 outside it will be that or very close to that with only body heat or other energy input helping
its never a good idea to introduce moisture to a cold damp atmosphere even with ventilation as you will replace cold damp air with cold damp air from outside

 

[nick60]

Agree that inside average temp will be the same as the outside average temp in the long run, but the idea of the insulation would be to smooth out the peaks and troughs

 

[endecotp]

That would be a waste of celotex.
To "even out the peaks and troughs" you would need to put the insulation on the outside of the walls, so that the thermal mass is inside. It would still be pretty pointless, and a huge waste of money, though.

 

[John D v2.0]

Should be warmer since it shares at least one wall with the house.
But agreed for drying you need heat and ventilation. Or dehumidifier

 

[^woody^]

If it's not heated it will be cold, and you may as well use just wallpaper - which could look pretty depending on your taste.

As for drying kit, then any extractor is just going to pull cold air in. Cold humid air for most of the year.

I'm not clear what you are actually doing, but if kit is clothes, (or even if its not), then a heater to warm the air, which will then hold much more moisture and a little air vent to move the air (mostly outwards) will be the best way. And then if you are heating it, then insulate it as you propose, and pay attention to taping the insulation joints and sealing gaps.