Rigid Foam Insulation Under Roof Deck

Install rigid insulation board in multiple layers with joints offset vertically and horizontally between adjacent layers.

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. Install nailbase for cladding. This type of insulated roof assembly limits thermal bridging through rafters. Position the foam board between the rafters and push it upward until it fits snugly against the underside of the roof deck.

The energy argument is argumentative. 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. After installing several layers of rigid foam above the roof sheathing these workers installed plywood above the rigid foam. Polyurethane spray foam metal roof insulation in order to add moisture barrier under metal roof you can spray the undersides of the roof by using a thick layer of polyurethane spray foam.

This can be perlite concrete vermiculite concrete concrete made with polystyrene aggregate or cellular concrete. Strip the old roof lay down ice and water membrane add the foam overlapped screw down the 2x4 s add sheathing shingle. 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. The snugness of the foam itself should be sufficient to hold the strips.

Rigid insulation layers exterior to existing roof sheathing must provide sufficient thermal insulation r value to control condensation risk see climate specific guidance. A good rigid insulation is insulating concrete which can be mixed and placed on the job. 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. 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.

Rigid foam under roof sheathing indydog.