OSB Size For Covering Wooden Frame (Outdoor Workshop)

[Skavenger]

I'd get the 18mm, with a load of screws in, it will be pretty strong.
PS, don't think they do 50mm rockwool, I was just commenting on thermal values.

Do you mean the 11mm OSB2?

 

[Mr Chibs]

I wouldn't be worried about structural or not, as it's a shed, but my preference would be 18mm not the 11.
I'd pay the extra over the 11mm

 

[Skavenger]

I wouldn't be worried about structural or not, as it's a shed, but my preference would be 18mm not the 11.
I'd pay the extra over the 11mm

Also more to screw into for shelves etc in case I can't pick up a stud or noggin I guess

 

[Skavenger]

Here is a cross section of how I understand the structure / insulation:

11mm OSB 3 fitted to the inside of the timber frame.
50mm Rockwool / Celotex or Kingspan fitted up against the back of the OSB.
20mm Air Gap (Due to 70mm wide timber frame)
Breathable Membrane stapled to the outside of the timber frame
Battens screwed / nailed through the membrane into the timber frame
Cladding fitted to the battens (Either wood or plastic TBC).

Just recapping on this. I have stapled the breathable membrane to the outside of the timber and fitted Knauf OmniFit 50mm rock wool slabs in between the studs on the inside. B fore I cut and fit the OSB on the inside please confirm that I DO NOT need a vapour barrier between the OSB and rock Wool?

Thanks