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Should I vent enclosed soffits on a house with an unvented cathedral ceiling?

Hi,
We're in zone 4C at 1550 feet. Building a log house. We're planning on an unvented cathedral ceiling (2 in. closed cell spray foam with balance of rafter bay filled with additional insulation). The roof (12/12 pitch) is shingled at this point in time. We utilized I beam style rafters. We wanted to use cedar T&G planks on the underside of the soffits (4 - 5 feet wide). We hope to have a few recessed can lights in the gable soffits. Should we vent the soffits? If so, how? Or is the T&G "leaky" enough for ventilation. It's rather wet here, 30's to 20's for periods during the winter, 70's with sun during summer. Concerned about moisture in enclosed soffitsLeaving soffits open won't work. Can't find recommendations for this issue! Thanks.

Asked by Rick Schneider
Posted Thu, 11/29/2012 - 00:05

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2 Answers

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Rick,
You don't need to vent the soffits.

But there are several concerns you haven't mentioned.

First of all, if you want to install can lights in an outdoor soffit, you have to be sure that they are appropriate for a damp environment. Otherwise, the trim will rust, and they'll look terrible.

Second, these can lights will create hot spots that have the potential to melt snow on your roof and contribute to an ice dam. I don't know how much snow you get in your area, but you don't want hot spots on your roof. You may be able to address this issue with some rigid foam.

Third, you need to maintain adequate clearances to prevent the can lights from overheating.

Answered by Martin Holladay, GBA Advisor
Posted Thu, 11/29/2012 - 06:53

2.
Helpful? 0

Thanks for the advice and putting our minds at ease. We'll use LED bulbs to reduce heat. Not too much snow, but we can always leave the lights off if there is an accumulation.

Answered by Rick Schneider
Posted Thu, 11/29/2012 - 10:34

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