Hi,
I’m planning to build a music studio in my garden.. I’m 80% there with the design, but need some advice regarding cladding the roof. I'm keeping it small enough that I won't have to meet building control requirements, but I still want to do the job properly.
The plan is for a pitched roof design and I want to use either box profile or corrugated metal sheeting to clad it.
I’m thinking from an acoustic and thermal insulation perspective, to go for a decent thickness of PIR insulation between the rafters, then a layer of OSB sheathing on top, then a membrane, but I’m not sure of the correct way to then attach the metal sheeting on top.
All the manufacturers guidelines I can find for this type of material suggest attaching it to thick purlins, but they are all aimed at building a barn or workshop roof with no mention of wood sheathing or insulation below. I have found several videos on youtube (all from America), where people are using this material on houses and are laying the metal directly on top of the OSB (and membrane) and are using foam packers at the ends, but I feel like restricting airflow beneath the metal might be an issue?
Basically my question is:
On top of the joists should I go OSB>membrane>metal roofing sheet or OSB>membrane>some sort of battens (or larger purlins)>metal roofing sheet.
I feel like any sort of horizontal battens will prevent any drips from running downhill, but no battens might restrict airflow. What’s the proper way to do this?
Thanks,
Jamie
