Hi Art,
Ed is absolutely on the money. You will find info www.buildingscience.com
There is a correct ratio between rooftop and soffit venting. Too tight a soffit opening cfreates a funnel effect. I had my roof redone last year and increasd the rooftop vents.
The upper level is noticeable cooler in summer now and I am upgrading insul to R50 as well. I am also adding venting in the plywood soffits by doubling the grille dimension and adding additional ones. You can also install a liner baffle attached to the underside of the roof which channels air above the insulation up toward the roof top while retaining the insulation above your wall's top plate.
FYI if you have a home energy audit done for about $300 before you add the insul you will likely get a provincial/federal rebate which covers most of if not all of your entire cost. Then apply for the new HRTC home reno credit and you'll be money ahead:thumbsup:
Ed is absolutely on the money. You will find info www.buildingscience.com
There is a correct ratio between rooftop and soffit venting. Too tight a soffit opening cfreates a funnel effect. I had my roof redone last year and increasd the rooftop vents.
The upper level is noticeable cooler in summer now and I am upgrading insul to R50 as well. I am also adding venting in the plywood soffits by doubling the grille dimension and adding additional ones. You can also install a liner baffle attached to the underside of the roof which channels air above the insulation up toward the roof top while retaining the insulation above your wall's top plate.
FYI if you have a home energy audit done for about $300 before you add the insul you will likely get a provincial/federal rebate which covers most of if not all of your entire cost. Then apply for the new HRTC home reno credit and you'll be money ahead:thumbsup:
