Depending on your house interior and roof framing design cathedral ceiling ventilation can be treated as an independent or attic ventilation related condition.
Roof ventilation for vaulted ceilings.
It s better than having the water sandwiched between the sheathing and spray foam.
A ridge vent features an open strip along the length of the ridge where the air that enters the soffit can escape.
Because the roof isn t in play here it doesn t matter how many hips valleys dormers or gables there are.
In a vaulted roof a ridge vent serves as the outtake or exhaust vent.
Properly insulated cathedral ceiling assemblies incorporating air and vapor retarders can.
Attic ventilation for cathedral and vaulted ceilings require attic baffle vents with v baffe s design you can quickly and easily retrofit cathedral and vaulted ceilings that would otherwise have been next to impossible.
Ventilation of vaulted ceilings vaulted ceilings sometimes referred to as cathedral ceilings occur in steep slope roof assemblies in which there is no attic space between a ceiling and roof deck.
As much as regular attic ventilation is an important part of your house maintenance routine and usually easy to perform cathedral ceiling ventilation maintenance might be difficult or even impossible to do.
Chimneys recessed lights plumbing chases and holes drilled through top plates for plumbing or wiring should all be sealed figure 2 53 at left.
Proper ventilation even with the attic bypasses sealed and effective vapor retarders installed proper ventilation is essential to prevent moisture problems in cathedral ceilings.
A balanced system of soffit and ridge ventilation provides continuous ventilation of hot moist air at the hottest point of the roof.
In mixed climates ventilation serves either role depending on the season.
Vaulted ceilings can be constructed by either stick framing which means attaching each joist and rafter individually or by setting roof trusses that come engineered from a truss manufacturer.
When renovating an older home whose roof rafters are only 2x6 really 5 1 2 x 1 5 in dimension the available space for insulation and ventilation is limited therefore limiting the options for a combination of good under roof ventilation and high insulation r values in the cathedral ceiling.
The air space above the insulation will provide some relief in the event of a roof leak even without ventilation.
As for how much insulation to use the minimum would be a 2 inch board which will get you about r 12 plus a little extra from the foil facing.