The movement of air into indirect conditioning of an unvented attic is a slow gradual process that will not be noticeable by occupants and typically will not put any strain on the hvac system.
Spraying insulation to the underside of a roof.
Uneven or sloppy application however can make the insulation ineffective and unsealed open cell insulation can absorb moisture causing the roof to rot or leak.
Spray foam insulation also called spray foam or spray polyurethane foam spf is an alternative to traditional building insulation.
Closed cell insulation will not allow water to pass through it.
As well as a number of diy sites.
When it comes to spray foam insulation that is applied to the underside of the roof between the rafters the financial benefits are even more impressive with the initial outlay recouped within just a few years on average.
So what is the spray foam.
The 3 foot roof panels will be anchored to purlins that run diagonal to the rafters.
Convenience 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.
Can you spray foam the underside of your roof.
Spraying foam on the underside of your roof is a great way to stop air from flowing out of the top of your house.
Yes you can spray foam the underside of your roof.
However i do have a concern about spraying foam directly on the underside of the roof sheathing and rafters.
I would like to avoid installing sheathing if possible extra waste but i don t want to compromise the r value of the spray foam or to have the foam ooze out between the metal panels as it expands.
The spray on foam is a rigid foam that is lightweight normally sprayed on to the underside of the roof approximately 50 to 100 mm thickness.
You can spray foam anywhere you d like to separate the inside from the outside.