Just after some advice. I am looking to insulate my shed for all year round use. I have looked on various forums and now more confused than ever.
The shed was a bespoke prefab made into a number of panels with 70mm deep stud frame, a breather membrane and then 20mm outer cladding. The breather membrane is almost tight against the inside of the cladding. (I thought normally there should be a gap, but it is what it is)
I would like a little sound proofing and so decided to go with rw3 rockwool. 35mm. And yes I do know at that thickness it wont make a huge difference. However, I have read insulation should have an air gap between the cladding and the insulation.
The next issue I have is that rockwool is to some extent flexible and will sag slighty over time and I need to somehow keep it away from the cladding, so from outside to in - I was going to put spacers on the inside of cladding(with breather membrane) then push/ fit 15mm celotex board up to this(leaving an 20mm air gap) Then push the rockwool up to the celotex filling the rest of void. Then a vapour barrier and then soundbloc plasterboard.
As I'm sure most of you will say, I have no idea what I am doing and you would be right!
How can I make this work? Or at least make the best of a bad situation, as I have already bought the materials. How do I leave an air gap and stop the rockwool falling on the cladding at some otherwise?