Rigid foam board is just above the roof deck or an exterior insulation option.
Spray insulation roof deck.
When the choice is made to insulate along the underside of the roof deck spray foams have advantages over other insulation types because of the ability of spray foams to effectively air seal complex assemblies.
Yeah you probably still breathed some of it but not as much as you will now with spray foam on the roof deck.
As air impermeable insulation spray foam insulation can be used in such applications.
This retrofit assembly is appropriate for homes with conditioned attics or where the retrofit is intended to create a conditioned attic.
By encapsulating the attic and leaving the old insulation up there that filth is in your conditioned space.
Your indoor air quality may get worse.
You may have odor problems.
Air permeable insulation applied to the underside of the roof deck with minimum r 10 rigid insulation above the roof deck.
Insulate an attic in an existing home by installing spray foam open cell or closed cell on the underside of the roof deck.
Air permeable insulation applied to the under side of minimum r 10 air impermeable insula tion spray foam or rigid board which is applied directly to the underside of the 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.
Spray foam insulation applied on the underside of the roof deck in cold climate commercial buildings allows for a significant reduction in condensation potential particularly compared to interior air permeable batt systems.
It typically has 3 variations.
It s not coming from above the roof and it s not some new moisture source resulting from the spray foam.
Inspect the existing roof shingles or roofing membrane for any deficiencies.
Lstiburek takes blame for bad language.
Remove existing roofing and non adhered underlayment to expose roof sheathing.
Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls.
Bare foam board one sided sheathing board or double sided which is also reference as structural insulated panels.
The last requirement is the installation of your shingles must be performed in strict accordance with the owens corning installation instructions.
All spray foam insulation radiant barrier and other components of the roof deck must be installed in accordance with manufacturer s installation instructions.
Moisture generated indoors or that infiltrates into the home is responsible for the bulk of the moisture in an attic insulated with spray foam on the underside of the roof sheathing.
The installation steps are as follows.
Install insulating sheathing above the roof deck on existing homes.