I'm hoping someone might be able to help me on insulating my roof. I've been to a few websites and I've had a bit of conflicting advice. Here is the relevant information:
I have Kingspan insulation panels, 100mm thick.
The roof is flat, with an exterior surface of fibreglass, which rests atop OSB, which rests atop timber joists.
The shed is 6m x 5m and constructed of single skin breeze block.
The floor is of poured concrete.
It has one standard sized door and the only ventilation is when I leave the door open, or the two small windows above the door. Other than the entire shed itself not being airtight of course.
I intend spending a good few hours in there each day because I am doing carpentry/woodworking projects. So I need to keep the condensation and moisture down to manageable levels because even now, some of my tools are starting to show spots of rust and it's only been a few months.
If it helps, the block walls have been rendered. And the floor has had DPM fitted.
I've supplied a pic of one of three possible configurations, and so far (C) seems to be the popular recommendation at 2 recommendations to 1 for (A).
So with all the above information, which configuration would you say is best for me to manage condensation/moisture levels? I don't want to fit the Kingpsan the wrong way and have water vapour ruin things.
Any advice would be greatly appreciated.
Thanks all.