It typically has 3 variations.
Spray insulation roof deck.
This measure will convert a vented attic to a nonvented attic.
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.
This retrofit assembly is appropriate for homes with conditioned attics or where the retrofit is intended to create a conditioned attic.
The installation steps are as follows.
It s not coming from above the roof and it s not some new moisture source resulting from the spray foam.
Your indoor air quality may get worse.
Rigid foam board is just above the roof deck or an exterior insulation option.
As air impermeable insulation spray foam insulation can be used in such applications.
Yeah you probably still breathed some of it but not as much as you will now with spray foam on the roof deck.
The later is used in new construction as the interior board serves as an inner wall.
Insulate an attic in an existing home by installing spray foam open cell or closed cell on the underside of the roof deck.
Install insulating sheathing above the roof deck on existing homes.
By encapsulating the attic and leaving the old insulation up there that filth is in your conditioned space.
Remove existing roofing and non adhered underlayment to expose roof sheathing.
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.
Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls.
All spray foam insulation radiant barrier and other components of the roof deck must be installed in accordance with manufacturer s installation instructions.
The spray foam can also serve as the thermal and vapor control layers in both new and retrofit construction.
The last requirement is the installation of your shingles must be performed in strict accordance with the owens corning installation instructions.
Lstiburek takes blame for bad language.
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.
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.
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.