Exterior Roof Insulation Details

The 6 inches of rigid insulation added to the top of the existing roof deck needed to be done in a manner that was invisible.

Exterior roof insulation details.

Rigid insulation layers exterior to existing roof sheathing must provide sufficient thermal insulation r value to control condensation risk see climate specific guidance. Gable end detail overhang cut and then rebuilt to hide the thickness of the over roofing rigid insulation. The binder includes product specifications detailed drawings and illustrations technical datasheets and a number of informational brochures. Thermalwall ph rigid eps insulation board for insulating the exterior walls of homes the advantages are plenty here panels are between 4 5 inches and 8 inches thick the exterior insulation is continuous and they can be attached with 6 inch 10 screws from 4 to 6 inches long.

Rockwool multifix is a mineral fiberglass faced stone wool product that can be installed under many single ply membranes. Now comes the really really big point. Install nailbase for cladding. Install two layers of insulation to the roof staggering the seams offsetting the joints and taping outer layer.

When insulating foam is used to wrap the exterior of a home it provides an undetected pathway connecting soil to structure. Insulated roof assemblies can be vented or unvented. Single ply roof systems can provide an easy to install seamless roof assembly. Install roofing underlayment flashing and cladding as per best practices.

Single ply roof insulation. Current building code does provide prescriptive means to attach cladding over exterior insulation table r704 3 note v. If you are planning to install metal roofing then you would install asphalt felt above the rigid foam followed by 1x4 or 2x4 purlins 24 inches on center then the metal roofing. Extend the foam 4 inches past the walls so that you can add foam to the walls later and tie it in to the roof.

Roof edge detail overhang extended to hide the thickness of the over roofing rigid insulation. The easiest way to insulate your roof is with one or two layers of rigid foam insulation installed above the roofing. New roof sheathing on top can extend out to create a new roof overhang. Nailbase must be vented in high snow load areas.

There are at least two good reasons why this approach makes more sense than installing the insulation under the roof sheathing. Building codes are clear. There are lots of different ways to insulate this type of roof but one of the best methods calls for the installation of rigid foam insulation above the roof sheathing. Termites can tunnel from the soil up behind the foam panels and attack the structure of a house without being noticed.