We are getting ready to add a 21′ x 21′ addition to our house. The one story addition will have a loft under a gambrel roof. Does anyone have experience with insulating, what effectively is a cathedral ceiling?. I guess my primary interest is it is better to install a insulation baffle from the soffit vent to the ridge vent or to stick with a shorter version that runs just a couple feet from the soffit. The rafters will be 2×8. thanks.
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Depends. If a low slope and you use cellulose ... just a baffle at the bottom ... the manufacturer may tell you what the limits/conditions should be. Steep ceilings/roofs should get baffles all the way up, I think.
For fiberglass batts, I'd baffle the bottom and take care installing the rest to ensure an air space is maintained. Don't install 12" insulation in a ceiling structure only 11.5" deep.
Food for thought
Here is a rough drawing of where we think we are going. Thanks for the input
If you are finishing and insulating the ceiling then you have 2 options.
1 have low vent, high vents, and maintain an air space between the from top to bottom.
Dependeing on the insulation and the way tht it is installed that might form the air channel or you might be baffles the whole way.
Or you could make it a "hot roof" and have continous insulation and no air flow.
IN any case with 7 1/2" you will probably need to build out and install insulation over top of the rafters.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.