Foam Board Roof Decking

For new construction use rigid boards to insulate slabs and the outside of foundation walls.

Foam board roof decking.

This section outlines the conditions for unvented attic roof assemblies. Given that it seems that the ideal roof deck build up would consist of. I am curious as to whether the first layer of osb could be omitted if the foam board did not react to. 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.

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. The snugness of the foam itself should be sufficient to hold the strips. Top surface is sealed with this special coating to reduce excessive asphalt absorption in hot asphalt applied roofing systems. Frothpaks or 5 for 1 part foam cans.

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. 1 4 spans flute widths up to 2 5 8 flexural strengths parallel lbs. Attach the tongue and groove insulation boards to the concrete wall with adhesive. Position the foam board between the rafters and push it upward until it fits snugly against the underside of the roof deck.

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. Use a premade kit for this type of project. For a basement remodeling project consider insulating basement walls with foam board. Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic 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. Rigid roof insulation board. R values 28 tested in accordance with astm c518 spannings. 1 4 dens deck roof board.

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. 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. I m planning on open cell spray foam on the underside of the roof deck.

After the roof deck is prepared the rigid foam boards need to be cut to size to fit snugly together on your roof.