Loosely related to above issues, during the very cold snap in the UK early December last year temperatures dropped to as low as -8°C and remained long enough for everywhere to get a cold soak including the inside of our new build double garage. This was followed before Christmas by a sudden increase in temperature with the high moisture air without the benefit of breeze, condensing on everything within garage. The Morgan despite dust cover was covered absolutely everywhere inside and out with moisture, and particularly noticeable under the hood with all engine and electrics literally dripping with it.
As I'd already had trouble with moisture damaging pictures hung on the single brick side walls I decided to insulate the pitch roof of garage using 50mm Celotex. This comes in 2.4 x 1.2m sheets and by cutting into strips, wedged it between roof truss A frames leaving the recommenced 50mm air gap between roof felt and insulation when it was pushed flush into place. Whilst very easy to cut this took a while as each set of strips had to be custom cut due to variations in spacing of A frames but was complete within a week after using 16+ sheets. The ends of strips were joined together with gaffer tape. I've since added profiled rubber strips under each of the cantilever up and over doors to fill the suprisingly large gap under them. Design of doors still allows plenty of ventilation though.
Already I can feel the walls are less damp and my breath doesn't show up inside during subsequent cold weather. Also comfier to work inside
