If you install just one layer you ll need to fasten the osb or plywood to the concrete slab with long tapcon screws that extend through the rigid foam.
Roof blocking on top of rigid.
Rafters rest on the top wall plate.
I resided 17 years ago over one layer of continuous rigid insulation.
The plywood was fastened through the rigid foam to the rafters with long screws.
Install rigid insulation board in multiple layers with joints offset vertically and horizontally between adjacent layers.
Rafters are nailed to the plate not framed into it.
Stagger the joints to.
Then on top of the rigid thermal insulation there should be a coverboard.
Make sure there is sufficient soffit venting.
Some are cut to fit the plate while in hasty construction they are merely laid on top of the plate and nailed in place.
Butt the ends of the boards up together.
Apply a new roof deck over the 2x4s and dry in with roofing felt or impermeable synthetic roofing underlayment.
Install nailbase for cladding.
The type of roof.
This coverboard is also screwed down to the metal deck.
This air seal is pretty darn good.
Align the insulation boards with the chalk lines and lay them onto the deck.
Rigid thermal insulation on the top of this air control layer in two layers at least with the joints off set horizontally and vertically.
The three layers of rigid insulation have yet to be installed over the top of the roof decking at this point.
Note that there was no air seal at this location originally.
Use a chalk box to snap chalk lines on the roof deck.
When we do complex roofs in high snow load areas like ski resorts we typically have the roof deck act as the air control layer and provide a high level of thermal resistance at the roof deck either rigid insulation directly above the roof deck or high density spray foam directly under the roof deck and then we provide an over roof creating a vented space over the top of the entire assembly.
Rigid insulation layers exterior to existing roof sheathing must provide sufficient thermal insulation r value to control condensation risk see climate specific guidance.
After installing several layers of rigid foam above the roof sheathing these workers installed plywood above the rigid foam.
This insulation should be screwed down to the metal deck.
They may extend a short distance beyond the wall to form the eaves and protect the sides of the building.
Ladder style blocking provides the structure of a torsion box which ties the fascia soffit.
I have to come clean here as well.
And roof overhang together into a beam.