Hi there.
Newbie question for all you helpful people out there. I am sure this question has been asked before, but I am still confused after reading through loads of posts.
I am building a recycled summerhouse from scratch and I am just about to lay the base. I have 100mm bearers that the floor sits on. My plan was to put 50mm Kingspan or celotex between them to insulate the floor leaving a 50mm gap below for the air to circulate below the building.
I have read that after around 7 years the insulation loses some of it's themal rating and becomes almost like traditional polystyrene.
I have also read that extruded stuff doesn't like the damp and so would probably be no good under the floor with possibility of getting damp.
Am I just better saving my money and buying 50mm standard poly?
Please help!!