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  1. #1
    Join Date
    Apr 2012

    Default how to ventilate house with exposed rafter tails w/ no soffit

    I bought a house last year built in 1912 and have been renovating it myself extensively. Right now I'm confused about how to best go about ventilating my attic. My house is 1.5 stories and I am currently building out the attic now. I am insulating with Owens Corning EcoTouch R-21 insulation since it is only 5.5 inches thick. My rafters are only 5.5 inches wide with half inch cross strips between the rafters and the roof decking. This will leave a little over a half inch for air to vent. I am currently in the process of cutting out and installing a continuous ridge vent.

    My dilemma is this: My house has exposed rafter tails with no soffit and I don't know how to creat an intake. I do not want to use SmartVent or cut into the roof. There is possibly a small amount of area I could cut between the rafter tails and fascia to install 1 inch louvre vents, but it is hard to gauge. I am going to build a 4' kneewall.

    So, I have two questions: 1) Will having a kneewall allow for enough air flow (without soffit vents) for the air to rise and exhaust to the ridge vent? 2) Is it absolutely necessary to have soffit or eave vents for my house to ventilate properly?

    I live in Tennessee and have attached some photos of my house. Thank you very much for any help!

    Well, I can't attach any photos here, it always says "invalid img file" even though they meet every requirement listed here.

  2. #2
    Join Date
    Jan 2009
    Needham, MA

    Default Re: how to ventilate house with exposed rafter tails w/ no soffit

    i'm trying to picture your dilema and i think i know what you're talking about. installing a ridge vent and installing insulation in the rafter bays is almost pointless. regarding the sofit venting, you have to install some type of vent so that air can enter the atic area. there are two options i can think of. 1 is to have closed cell spray foam insulation installed on the bottom of the roof. that will eliminate a need for a ridge vent and venting the bottom of the roof sheathing. but you should still vent the space behind the kneewall. 2 is to fir out the rafters so that you can install insulation with a higher "R" value and still fit baffles along the underside of the sheathing which will allow the air to flow from the sofit vents to the ridge vent.

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