I would like to add attic insulation to my son’s house; but have a couple of questions.
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It is a small (700+/-sf) house with a fairly steep gable roof with a room in the attic. I haven’t measured the rafters but they are probably 2×8 and there is little over hang.
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There is some insulation there now but just up to the top of the ceiling joists. (Loose fill)
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The attic is vented at the top but if there were ever any soffit vents they were covered up when the house was resided (vinyl over the old wood siding). You can see rolls of fiberglass stuffed between the rafters down into the soffit.
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There have been no problems with ice dams or condensation yet ( have owned the house for only one year).
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Questions
If we add blown in cellulose behind the knee walls without fixing the soffit vents are we asking for trouble?
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There is a cold air return for the attic room that is behind the knee wall. It is taped but not insulated. Can we just pile cellulose up over it when we shoot it in the attic?
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thanks
Replies
Greetings Chris,
This post, in response to your question, will bump the thread through the 'recent discussion' listing again which will increase it's viewing.
Perhaps it will catch someone's attention that can help you with advice.
Cheers
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My house doesn't have soffit vents either. It's an old Edwardian, in San Francisco, so cold weather isn't a consideration, but the attic does get hot when the sun shines. My guess is that the old houses were leaky enough not to need the vents. I had a look behind my knee walls recently, and the stud bays are open down to the main floor (balloon framing), with no sheathing behind the clapboards.
I'm planning to fill the stud bays with cellulose, which would reduce the incoming leaks/ventilation a lot, so I'm considering putting in vents.
If you're not experiencing ice dams or condensation with minimal insulation, then you won't with additional.
Go ahead and blow as much cellulose as you'd like. It will not only improve the insulation value but also decrease exfiltration through the ceiling and improve fire-resistance. Make sure it's borate, not ammonium sulfate, treated. The sulfate will corrode metal fasteners.
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