Foam Board Roof Decking

The panels need to fit together tightly to help prevent warm air from leaving the top of the building.

Foam board roof decking.

Given that it seems that the ideal roof deck build up would consist of. Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls. Frothpaks or 5 for 1 part foam cans. For new construction use rigid boards to insulate slabs and the outside of foundation walls.

Attach to deck board. 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. Position the foam board between the rafters and push it upward until it fits snugly against the underside of the roof deck. Rigid roof insulation board.

1 4 dens deck roof 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. R values 28 tested in accordance with astm c518 spannings. 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. 1 4 spans flute widths up to 2 5 8 flexural strengths parallel lbs. Use a premade kit for this type of project. Top surface is sealed with this special coating to reduce excessive asphalt absorption in hot asphalt applied roofing systems.

Attach the tongue and groove insulation boards to the concrete wall with adhesive. The snugness of the foam itself should be sufficient to hold the strips. Johns manville r panel rigid roof insulation board offers r values of up to r 23 6 providing high thermal efficiency. 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.

I am curious as to whether the first layer of osb could be omitted if the foam board did not react to. I m planning on open cell spray foam on the underside of the roof deck. 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. After the roof deck is prepared the rigid foam boards need to be cut to size to fit snugly together on your roof.

This section outlines the conditions for unvented attic roof assemblies.