Insulate vaulted ceilings?

[JoeBastian]

Looking for some idea on how to insulate the 2x6 gap in between the ceiling and the plywood (roof). Builder put 4in rigid foam in the gap leaving an extra 1.5in that I'd like to fill.


Thanks


Joe

[Slade]

Home Depot does carry 1.5" foam board, currently showing $28.84 for a 4x8 sheet. I see 2" fiberglass too, but probably more expensive than the foam board.

You might talk to All Valley Insulation. They do the spray foam that really fills the gaps, but it isn't cheap and I'm not sure that they would do it over the existing foam board. They also do fiberglass batting and might be able to help there.

Bob

[Mike K]

Not knowing how house this is vented I would be careful about filling this in. The last thing you want is mold. You must have air movement to keep mold and ice dams in check. Get a roofing contractor to check it out. Your building must breathe also.

[moose]

Ditto mike k.
Cold roofs are designed to breathe. Make sure you are not removing necessary designed vent space. Usually speckd at 1” min

[JoeBastian]

Thanks for the replies. Switching from a cold roof with venting to a warm roof without venting. I'm putting in foam board on top of the plywood. But will need to seal the 1.5in venting somehow.

[funhog.fundogs]

Warm roofs can be notorious for ice dams in the winter. The Ice can push water up under the shingles, the n eak down inside the house.