Roof Blocking On Top Of Rigid

This type of insulated roof assembly limits thermal bridging through rafters.

Roof blocking on top of rigid.

The three layers of rigid insulation have yet to be installed over the top of the roof decking at this point. Rafters are nailed to the plate not framed into it. After installing several layers of rigid foam above the roof sheathing these workers installed plywood above the rigid foam. This is the method a friend and i did in his basement.

Some are cut to fit the plate while in hasty construction they are merely laid on top of the plate and nailed in place. Align the insulation boards with the chalk lines and lay them onto the deck. Rigid insulation layers exterior to existing roof sheathing must provide sufficient thermal insulation r value to control condensation risk see climate specific guidance. This insulation should be screwed down to the metal deck.

Note that there was no air seal at this location originally. This coverboard is also screwed down to the metal deck. Rafters rest on the top wall plate. The type of roof.

Stagger the joints to. Rigid thermal insulation on the top of this air control layer in two layers at least with the joints off set horizontally and vertically. Apply a new roof deck over the 2x4s and dry in with roofing felt or impermeable synthetic roofing underlayment. Install one or two layers of tongue and groove osb or plywood on top of the rigid foam.

Install nailbase for cladding. And roof overhang together into a beam. Install rigid insulation board in multiple layers with joints offset vertically and horizontally between adjacent layers. The plywood was fastened through the rigid foam to the rafters with long screws.

I have to come clean here as well. 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. They may extend a short distance beyond the wall to form the eaves and protect the sides of the building. Use a chalk box to snap chalk lines on the roof deck.

I resided 17 years ago over one layer of continuous rigid insulation. This air seal is pretty darn good. Ladder style blocking provides the structure of a torsion box which ties the fascia soffit. 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.