Exterior Roof Insulation Details

Install two layers of insulation to the roof staggering the seams offsetting the joints and taping outer layer.

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. Single ply roof insulation. Minimum nail length must accommodate sheathing and penetrate framing a minimum 1 inches. Termites can tunnel from the soil up behind the foam panels and attack the structure of a house without being noticed.

Current pneumatic nailers have maximum fastener lengths of 3 to 3 5 which limits insulation thicknesses to 1 5 max. 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. Install roofing underlayment flashing and cladding as per best practices. Now comes the really really big point.

Install nailbase for cladding. Insulated roof assemblies can be vented or unvented. Current building code does provide prescriptive means to attach cladding over exterior insulation table r704 3 note v. 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. The easiest way to insulate your roof is with one or two layers of rigid foam insulation installed above the roofing. 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.

Single ply roof systems can provide an easy to install seamless roof assembly. Gable end detail overhang cut and then rebuilt to hide the thickness of the over roofing rigid insulation. Roof edge detail overhang extended to hide the thickness of the over roofing rigid insulation. When insulating foam is used to wrap the exterior of a home it provides an undetected pathway connecting soil to structure.

Nailbase must be vented in high snow load areas. Rigid insulation layers exterior to existing roof sheathing must provide sufficient thermal insulation r value to control condensation risk see climate specific guidance. 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. The binder includes product specifications detailed drawings and illustrations technical datasheets and a number of informational brochures.