Nothing unusual about that.
Spray insulation roof ventilation.
Earlier this year i got a question about a home that had spray foam insulation in the attic.
Rigid foam and spray foam are two of them.
Moving the air control layer and thermal control layer to the underside of the roof deck has significant advantages in cases where the hvac system is located in the attic.
Unlike solid insulation products that require careful measurement cutting and fitting spray foam can cover even the most uneven surface instantly.
The airflow from the soffits to the ridge vent keeps the roof cool and prevents ice dams and the material will block that flow.
Covering up the soffit vents with loose fill or batts which can happen if you stuff insulation along the eaves is a huge no no.
The most important thing to remember is to use the correct type of insulation and to ensure it is installed correctly.
For the same reason insulation shouldn t touch the roof s underside.
Unvented attic assemblies unvented attics rely on an air impermeable insulation installed to the roof deck s underside i e.
Care should be taken with these assemblies particularly in cold climate zone locations i e.
Polyurethane or polystyrene spray foams can provide thorough coverage to roof rafters and attic walls in much less time than is needed for other materials.
Spray foam insulation will not prevent ventilation and so there s no need to avoid it thinking that it will result in mould and mildew from building up inside the attic space.
Spray polyurethane foam is a chemical product that is created by two materials isocyanate and polyol resin that will react with each other when they are mixed and will expand up to 30 to 60 times its liquid volume as it is sprayed in place.
Attic ceiling to stop airborne moisture from reaching a cold surface and condensing inside the building envelope in this design insulation effectively separates the interior and exterior spaces while slowing down moisture flow so the dewpoint is not achieved within.
All insulation materials require proper venting.
This illustration shows a sloped roof with cavity spray foam insulation sprayed on the underside of the roof deck and covered with sprayed on thermal or ignition barrier coating.
Heat from the house rises up to the attic but when there isn t one the heat rises up to the roof.
Cathedral roofs especially need a lot more insulation between the ceiling and the rafters because there usually isn t any attic space.
Zones 5 6 7 and 8 in that the manufacturers of these materials assume that roof deck may require ventilation to assist drying.