Rigid Insulation Over Plywood Sheathing

Rigid insulation over roof sheathing jdgengineer structural op 13 aug 18 17 14.

Rigid insulation over plywood sheathing.

It s made up of several thin layers of wood or plys which are laid in opposite directions to one another. Plywood has an r value of 1 25 and fiberglass batts have an r value of 3 14. Plus rigid foam insulation applied over the outside walls. Cladding attachment over thick exterior rigid insulation background current building code does provide prescriptive means to attach cladding over exterior insulation table r704 3 note v.

Plywood is a frequently used material for external structural sheathing. Plywood sheathing image credit. Osb sheathing tyvek house wrap 1 xps with taped seams vinyl siding my builder was going to put the xps foam directly over the sheathing and then was going to wrap the house over the top of the foam. Box beam gable framing new gable overhang is framed in the form of a box beam hanging off of a new layer of roof plywood roof sheathing cantilevered over the top of the 3 layers of rigid insulation.

The foam on the outside keeps the wood frame inside the. Current pneumatic nailers have maximum fastener lengths. This creates a much more stable and structurally sound sheath that can be used over the exterior. Forming plywood medium density overlay plywood.

An additional layer of 1 2 plywood is proposed above the rigid insulation for attachment of asphalt shingles. More effective insulation with r values ranging from 3 6 to 8 0 rigid foam sheathing has much better insulation per inch than other materials i e. 3 benefits of rigid foam sheathing. We have a project that will have 1 1 2 rigid insulation installed above the 5 8 structural roof sheathing.

The exposed edges of the 3 layers of rigid insulation are to be sealed with another layer of membrane. It adds up to a robust system. Zip system r sheathing is the simple all in one structural panel with built in exterior insulation. I just saw a video from dupont that this is how they recommend the installation goes.