Foam Board Roof Decking

Composed of a closed cell polyisocyanurate foam core bonded in the foaming process to retroplus roof board on one side and a glass reinforced facer on the other.

Foam board roof decking.

Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls. Rigid foam is produced in various size panels 4 ft x 8 ft 4ft x 4ft etc. After the roof deck is prepared the rigid foam boards need to be cut to size to fit snugly together on your roof. Use a premade kit for this type of project.

The panels need to fit together tightly to help prevent warm air from leaving the top of the building. Attach to deck board. 1 2 rigid foam board 3. Rigid roof insulation board.

Johns manville r panel rigid roof insulation board offers r values of up to r 23 6 providing high thermal efficiency. 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. Frothpaks or 5 for 1 part foam cans. I m planning on open cell spray foam on the underside of the roof deck.

The snugness of the foam itself should be sufficient to hold the strips. 1 4 spans flute widths up to 2 5 8 flexural strengths parallel lbs. I am curious as to whether the first layer of osb could be omitted if the foam board did not react to. Top surface is sealed with this special coating to reduce excessive asphalt absorption in hot asphalt applied roofing systems.

This section outlines the conditions for unvented attic roof assemblies. This construction approach was first used in the 1970s and it has been implemented much more widely since it was first included in the international code council s icc model building code in 2007 irc section 806 4. For new construction use rigid boards to insulate slabs and the outside of foundation walls. 1 4 dens deck roof board.

For a basement remodeling project consider insulating basement walls with foam board. Given that it seems that the ideal roof deck build up would consist of. Foam on the underside of the roof deck would provide a more reliable air seal but has long term issues related to roof rot since the unvented roof deck would get a lot of. At 600 board feet you can get the spray foam cost down to about 1 20 board foot compared to 3 35 bf ft in the 12 b f.

R values 28 tested in accordance with astm c518 spannings.