Rigid Foam Insulation Under Roof Deck

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.

Rigid foam insulation under roof deck.

Additionally densdeck has been shown to withstand de lamination deterioration warping and jobsite damage more effectively than other roofing membrane substrates such as paper faced gypsum board fiber board and perlite insulation. The rigid insulation over roof would have controlled the temperature of the condensing surface the underside of the roof deck so that i would not have had to use the spray foam except at the perimeter to provide the air seal to the tops of the walls. Strip the old roof lay down ice and water membrane add the foam overlapped screw down the 2x4 s add sheathing shingle. Rigid insulation layers exterior to existing roof sheathing must provide sufficient thermal insulation r value to control condensation risk see climate specific guidance.

The unique construction of densdeck provides excellent flute spanning that stiffens and provides increased foot traffic resistance to the roof deck. Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls. It will help you to eliminate problems that may come when the house becomes extremely cold in the winter and terribly hot in the summer. Rigid foam under roof sheathing indydog.

The plywood was fastened through the rigid foam to the rafters with long screws. A good rigid insulation is insulating concrete which can be mixed and placed on the job. I agree with the comment that it sure is a lot of work for so little insulation our standard approach would be about 8 inches of xps screwed thru 2x4 s laided flat with timber loks. The snugness of the foam itself should be sufficient to hold the strips.

This can be perlite concrete vermiculite concrete concrete made with polystyrene aggregate or cellular concrete. Position the foam board between the rafters and push it upward until it fits snugly against the underside of the roof deck. This type of insulated roof assembly limits thermal bridging through rafters. Install rigid insulation board in multiple layers with joints offset vertically and horizontally between adjacent layers.

The energy argument is argumentative.