Rigid Foam Exterior Roof Sheathing

Install rigid insulation board in multiple layers with joints offset vertically and horizontally between adjacent layers.

Rigid foam exterior roof sheathing.

4 of polyiso under 4 of eps all above the original roof sheathing. Not only that foam sheathing will soon be mandated by code in some climate zones. Johns manville r panel rigid roof insulation board offers r values of up to r 23 6 providing high thermal efficiency. Zip system r sheathing is the simple all in one structural panel with built in exterior insulation.

We live in zone 5 suburb of chicago and are hopefully about to put rigid foam above the roof sheathing on just the northeast roof portion of our roof. Plywood has an r value of 1 25 and fiberglass batts have an r value of 3 14. Then a second layer of plywood sheathing and asphalt shingles following the steps explained in this article. R panel is manufactured with a closed cell polyisocyanurate foam core bonded to fiberglass reinforced facers and designed for use over metal nailable and non nailable roof decks with a variety of membrane systems.

The generic term is rigid foam sheathing or rigid foam insulation and it plays a direct role in a building s energy efficiency and performance. Rigid foam must be thick enough to prevent condensation on the roof sheathing. Rigid foam insulation also known as insulating boards provide high r values. They keep your home at a comfortable temperature without the need to crank your heat.

A lower layer conventionally nailed to the rafters and an upper layer installed as a nailing surface for the roofing material on top of the rigid foam. Install nailbase for cladding. Rigid insulation layers exterior to existing roof sheathing must provide sufficient thermal insulation r value to control condensation risk see climate specific guidance. Featuring integrated moisture air and thermal protection zip system r sheathing completely reimagines traditional wall assemblies by streamlining exterior water air and thermal management.

Here s what you need to know about this growing trend. The illustration shows two layers of osb or plywood roof sheathing. 3 benefits of rigid foam sheathing. By patrick mccombe issue 273 feb mar 2018 when combining exterior foam insulation with fiberglass cellulose or mineral wool roof insulation the foam layer must be thick enough to keep the sheathing temperature above the dew point.

Exterior rigid foam improves air tightness adds r value reduces the chance of condensation in wall cavities and greatly reduces thermal bridging through studs. Outsulation is the construction practice of placing a layer of insulation on the exterior side of the building. Rigid insulation is one of the best tools to reduce your energy costs. Install it anywhere from the roof to the foundation.