Rigid Insulation Roof Assembly

There s a reason polyiso rigid foam insulation is used in more than 70 of commercial roof construction as well as in many residential builds.

Rigid insulation roof assembly.

Assuming rafter construction is it best to build them like walls rigid insulation outside breathe to inside or is it best to seal the rafters on the inside with taped rigid foam and let the assembly breath to the outside. Owens corning foamular xps insulation is a closed cell moisture resistant rigid foam board ideal for many roofi ng applications including single ply protected roof membrane assemblies prma tapered vegetative roofs plaza decks architectural metal roofi ng and recover roofi ng. All of the rigid insulation board products work. There must be an air control layer air barrier under the rigid insulation boards.

The air control layer can be a fully adhered membrane on the roof deck or the air control layer. Polyiso is an easy cost effective sustainable and energy efficient construction material. Every one of them foil faced isocyanurate paper faced isocyanurate extruded polystyrene expanded polystyrene mineral wool aka stone wool rigid fiberglass. Rigid board insulation rigid boa.

Dual purpose structural deck and insulating planks. Lightweight insulating concrete lwic. Or sprayed polyurethane foam spf. Rigid foam also can be installed above the roof sheathing in tandem with air permeable insulation between the rafters.

Code specifies the minimum r value of the rigid foam layer. In this case the rigid foam can be thinner than when it s used alone. If all of the insulation is on the top of the roof sheathing this is pretty much a no brainer.