Rigid Insulation On Top Of Roof Deck

Most types of rigid foam insulation have a higher r value per inch than fiberglass batts.

Rigid insulation on top of roof deck.

The purpose of the requirement that rigid foam installed above roof sheathing meet certain minimum r values is to ensure that the roof sheathing stays warm enough during the winter to avoid moisture accumulation and possible sheathing rot. Rigid insulation layers exterior to existing roof sheathing must provide sufficient thermal insulation r value to control condensation risk see climate specific guidance. Rigid foam also does a better job of stopping air flow as long as it s carefully sealed at the edges. Polystyrene foam and foil faced polyisocyanurate foam.

Install nailbase for cladding. 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. Installing rigid foam insulation on top of roof sheathing is a great option for commercial buildings and homes with limited space. Nailbase must be vented in high snow load areas.

Foamular xps insulation products 404 604 404rb and 604rb are used in prma applications. Install roofing underlayment flashing and cladding as per best practices. Rigid foam is produced in various size panels 4 ft x 8 ft 4ft x 4ft etc. The panels need to fit together tightly to help prevent warm air from leaving the top of the building.

The trim the frieze boards the fascia and the overhangs all had to look like they belonged. They often simplify insulation and air sealing details versus conventional insulation on the floor of the attic that may be compromised by numerous penetrations from recessed lighting fans equipment and ductwork. Attach to deck board. Both install in the same manner but the foil faced product offers slightly more r value.

An excellent fire barrier densdeck roof boards feature a noncombustible core and inorganic surface that offer greater fire protection than other conventional commercial roofing products when applied over combustible roof decks and steel decks. Rigid foam insulation is available in two main types. Building air tightness would now preside at the top of the building enclosure at the roof deck and attic walls gables. Foamular xps insulation is the only insulation used in prma roof systems due to its excellent resistance to water absorption compared to any other type of rigid board insulation.

Installing stacks of rigid foam between rafters is slow fussy work but it might make sense for a do it yourselfer. After the roof deck is prepared the rigid foam boards need to be cut to size to fit snugly together on your roof.