I am starting to add insulation to my garden shed. I would like to be able to use my shed all year round, even if I have to spend more money on it. The roof seems impermeable, but I am not very confident the walls are, since they just shiplap wood cladding on a wood frame. That said, I have inspected the shed inside after heavy rain and I don't think water is coming inside.
My builder suggested to fit mineral glass wool on the walls and the roof for insulation. However, I have read online some people recommend fitting a breathable membrane before fitting the wool. Is this a good practice? Would this help prevent damp? I have already bought the wool, so I need to find a good solution that includes using it if possible.
Thanks a lot!