Foam Board Roof Decking

Top surface is sealed with this special coating to reduce excessive asphalt absorption in hot asphalt applied roofing systems.

Foam board roof decking.

Note that table r806 4 indicates the amount of insulation above the roof deck or air impermeable insulation below the roof deck required for condensation control assuming minimum required total insulation as indicated in section n1102 building thermal envelope. Johns manville r panel rigid roof insulation board offers r values of up to r 23 6 providing high thermal efficiency. 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. This section outlines the conditions for unvented attic roof assemblies.

For new construction use rigid boards to insulate slabs and the outside of foundation walls. 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. 1 2 rigid foam board 3. The panels need to fit together tightly to help prevent warm air from leaving the top of the building.

After the roof deck is prepared the rigid foam boards need to be cut to size to fit snugly together on your roof. For a basement remodeling project consider insulating basement walls with foam board. 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. The snugness of the foam itself should be sufficient to hold the strips.

R values 28 tested in accordance with astm c518 spannings. Attach to deck board. Rigid roof insulation board. Position the foam board between the rafters and push it upward until it fits snugly against the underside of the roof deck.

Rigid foam is produced in various size panels 4 ft x 8 ft 4ft x 4ft etc. 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. Attach the tongue and groove insulation boards to the concrete wall with adhesive. 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.

Use a premade kit for this type of project. Given that it seems that the ideal roof deck build up would consist of. I m planning on open cell spray foam on the underside of the roof deck. 1 4 dens deck roof board.

Frothpaks or 5 for 1 part foam cans.