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Discussion Starter · #1 ·
Hi all, newbie here. I have a question I was hoping I could get some assistance on answering. I have a smaller walk-in attic (16Lx12W open ceiling) with subfloor above our mudroom. We use it just for storage, but it gets brutally cold/hot in peak season. I’m located in MA. I’m not looking to “finish” the area, but I’d like to make it more comfortable to use. So I was going to insulate & drywall the walls & ceiling. My question is, what R value insulation to use? Again, it’s not living space. I’m also trying to keep the cost as low as possible. Thanks in advance for your assistance! John
 

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When you say ceiling, are you talking about the rafters below the roof sheathing?

Is there any ventilation up there, like ridge vents and soffit vents. High and low work best together.

Attics are intended to hot in summer and the house below is protected by lots of insulation and detailed air sealing. if you are storing stuff up there then difficult to have the recommended foot or more of insulation.

Gives us more details.

Bud
 

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Tall attic, gable vent, can't tell if there are soffit vents?

Two options.
1. basically the approach you described but more involved.
2. In the deep south they add a layer of reflective foil to the bottom of the roof sheathing. the good news is, it also helps here in the north. The option is to install something like 1" foil faced rigid insulation under the roof between the rafters.

Bud
 

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One picture does show insulation stuffed in the space we call soffits, so doubt there is any low venting. Without proper ventilation you risk moisture problems on the bottom of the roof. plus, codes in some locations prohibit fiberglass insulation up against the roof deck.

As for the bubble foil plastic I'm not sure how much it would add when covered with drywall. Those cavities should still be ventilated. No experience with that combination.

Bigger question is what the town building department will need to see. Your intended use has little bearing on what they require. if they see potential living space that determines the rules that need to be followed.

How is that space accessed?

Bud
 

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Discussion Starter · #12 ·
My orig plan was to pull out the stuffed insulation, install rafter vent/baffle, install R-19 on ceiling & sides and R-13 on far wall, then drywall over it. Thoughts?
Attics is accessed by a standard door
 

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R-19 would fill the rafter cavities completely leaving no room for ventilation. The risk of moisture damage is so high that some codes do not allow a complete fill.

In addition, your local authorities may want to see the full required insulation up there, guessing r-38 or more.

If you do not have a ridge vent and want to utilize the gable vent we see then you would need to create a ceiling below that gable vent, which doesn't look like it would work.

Sorry for bouncing all over the place but hard to offer a solution here.

Bud
 
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R-19 would fill the rafter cavities completely leaving no room for ventilation. The risk of moisture damage is so high that some codes do not allow a complete fill.

In addition, your local authorities may want to see the full required insulation up there, guessing r-38 or more.

If you do not have a ridge vent and want to utilize the gable vent we see then you would need to create a ceiling below that gable vent, which doesn't look like it would work.

Sorry for bouncing all over the place but hard to offer a solution here.

Bud
Not sure what to say about venting here?

 

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Discussion Starter · #18 ·
No it would better to figure out how to do it properly.

Is there a gap for air above that horizontal timber. could air get from the lower bay to the higher bay by going over top?
No, just checked. There might be a very slight gap, but I don’t think it’s by design.
 

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