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Does this “attic” need conditioned air?

Stockwell | Posted in General Questions on

The main section of our house (kitchen, dining, living rooms) that is under construction lies below a 3:12 pitch roof that will have R-49 insulation sprayed directly on the underside of the roof sheathing (a combo of closed cell and open cell foam in the correct percentages).

The ceiling below is flat and 16′ 9″ tall. The area from ceiling to even the peak of the roof is not much (maybe a few feet at the peak). The kitchen will have a drywall ceiling and the dining/living will have wood (+/- drywall depending on code). There are 6 can lights in the kitchen and none in the wood.

As HVAC is just starting, I am wondering if that area above the ceiling needs to have any airflow? Can I leave it as is or should I ask them to supply conditioned air and a return?

This is Zone 4A in the mountains of NC. My Manual J indicated  a significantly greater cooling load than heating load. I have gone to great lengths to air seal during construction (gaskets, caulk, Solitex Adhero, etc.). Thanks!

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  1. Peter Yost | | #1

    Hi Kevin -

    Martin Holladay has an article that addresses this question: Look under Question 5.


  2. Stockwell | | #2

    Martin has essentially written an article about everything--I should have searched harder!
    Closed cell foam-check
    Air sealed-check
    That answers that question!
    Thanks for the link Peter.

  3. aaronbeckworth | | #3


    Am I understanding you correctly, your flat ceiling above the kitchen, dining and living rooms will be 16’ 9”? I am having a hard time visualizing such a tall ceiling. I realize this is off topic, but I am currently in the planning stage and considering ceiling height options. Would you please confirm and maybe expand on your choice?


  4. Stockwell | | #4

    Aaron--yes, that is the ceiling height. There are clerestory windows on both sides right below the ceiling so it is very bright. Since it is so tall, we chose to put walnut wood planks on the ceiling. Dark wood makes it look shorter, but we have plenty of height to spare. In our case, this height was necessary because of the design of the house(some shed roofs on each end push up the main roof height). Make sure you go to other houses with tall ceilings to get a feel for the height. It's way taller than I thought it would be.

  5. aaronbeckworth | | #5

    Okay, I can visualize the clerestory windows and walnut ceiling. That sounds beautiful. Thanks for sharing.

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