Rigid Insulation Under Roof Deck

Nailbase must be vented in high snow load areas.

Rigid 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 installation after the roof deck is ready the rigid foam insulation is installed. Install nailbase for cladding. When installing a foil faced foam board insulation.

The unique construction of densdeck provides excellent flute spanning that stiffens and provides increased foot traffic resistance to the roof deck. For most of us in the low slope roofing industry it s considered to be absolutely standard to have insulation placed above the roof deck. Install roofing underlayment flashing and cladding as per best practices. 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.

Depending on the type of insulation you choose and the desired r value you want for your facility you may need to build up a few layers of insulation. When installing rigid insulation in an attic to be finished as a living space you must provide a route by which hot air. Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls. Rigid insulation layers exterior to existing roof sheathing must provide sufficient thermal insulation r value to control condensation risk see climate specific guidance.

For standard steel deck construction this approach has many advantages such as.