Insulating A Roof With Rigid Foam

There are at least two good reasons why this approach makes more sense than installing the insulation under the roof sheathing.

Insulating a roof with rigid foam.

A continuous layer of rigid foam insulation in wall and roof assemblies leads to lower energy consumption an environmental plus to be sure. But one thing that some builders don t like is the high global warming potential of some blowing agents used to make the foam. Eps is also the most inexpensive of the three types of rigid foam insulation while also meeting the required building and energy codes. Install rigid insulation board in multiple layers with joints offset vertically and horizontally between adjacent layers.

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. Rigid foam boards come in different material compositions varying thicknesses and different insulating r value properties. Nail it around the edges with roofing nails. It can be applied on the roof floor and walls and it s most widely used in structural insulated panels and insulated concrete forms.

Insulated roof assemblies can be vented or unvented. Eps is by far the most versatile of the three rigid insulation options. Rigid insulation layers exterior to existing roof sheathing must provide sufficient thermal insulation r value to control condensation risk see climate specific guidance.