Ventilation is not needed in attics with spray foam insulation because sealed attics that have spray foam applied on the underside of the roof sheathing (the attic's ceiling) should be airtight, ie they are thermally and physically closed off from the outside world.
Can you leave spray foam insulation exposed?
The quick answer is yes and no, because spray foam can be left exposed in some areas of the home with others require a thermal barrier according to the code. If the area of the home that has been sprayed with foam is directly connected to the living space, then it has to be separated by a thermal barrier.
What are the disadvantages of spray foam insulation?
List of the Cons of Spray Foam Insulation
- Spray foam insulation does not always fill every possible cavity. ...
- Spray foam insulation might encourage water damage for some homeowners. ...
- Spray foam insulation can sometimes shrink. ...
- Spray foam insulation requires a lot of experience to get it right.