attic remodel insulation

Discussion in 'Insulation and Radiant Barriers' started by peter_cottontail, Oct 24, 2009.

  1. Oct 24, 2009 #1

    peter_cottontail

    peter_cottontail

    peter_cottontail

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    Greetings! I'm new to the forum and I'm trying to find help with a question I haven't been able to answer on the net. I'm thinking/wanting to remodel my unfinished attic to make living space out of it. Right now it's insulated on the floor with gable vent and vented soffits. I know that I have to insulate the rafter space with baffles and seeing as though the soffits are vented already I'd like to just put a ridge vent in. However, my rafters are 2x6's and I cant afford to waste head space by increasing the depth. I live in Minnesota, so I know that R-value is a premium here. I read somewhere that 6" of fiberglass insulation is only an R-value of 19? Is that true? And if so, what's my best bet to get a higher R-value without compromising the headroom. I was thinking the blown in closed cell foam insulation, but does anyone have a rough idea what that costs? Also, I read that if I do go with that type of insulation, venting isn't necessary though I can't imagine that to be true. Anyways, as you can see I'm in the beginning stages of this project, but I figure planning the insulation to be the best start. Any help is greatly appreciated!
     
  2. Oct 25, 2009 #2

    inspectorD

    inspectorD

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  3. Oct 26, 2009 #3

    GBR

    GBR

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    Use 4 of these between the rafters without the baffles (keeping the 1-1/2" air space), and 1 on the face of the rafters under the drywall. Dow at Lowe's: 1" x 8' x 4' R-6.5 Polyisocyanurate Rigid Foam Insulation
    1. Do you know proper knee-wall insulation installation?
    2. Are the floor joists rated for floor or attic?
    3. A window is required for proper light and ventilation and possible egress requirements, sized per code.
    Be safe, Gary
     
  4. Oct 26, 2009 #4

    handyguys

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    I have done this project. There are a lot more considerations beyond insulation and head space as GBR said. When I did it R21 (as I recall) was to code. It likely isnt not now in my area.

    So yeah, this may actually be a good place to start. Find out if you will need to rebuild or raise the roof to accommodate insulation requirements. You will have a lot more flexibility with layout too if you go that route.

    On my project I built a 40' shed dormer on the back and two doghouse style dormers on the front.
     
  5. Oct 26, 2009 #5

    peter_cottontail

    peter_cottontail

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    thanks for the responses everyone; I'm having an architect come to determine the structural stability of the floor joists. My home was built in 1922 and the attic space is rafters with some purlin-strut supports along the sides. I'm thinking of substituting the struts for kneewalls and adding a few dormers to meet code for the living space. As far as windows are concerned, I have to get new windows to replace the gable vents. Basically, I'm just in the planning stages and not ready to begin this project with winter looming. I was just looking for information on an effective insulation tactic without compromising headroom so thanks everyone!
     
  6. Oct 26, 2009 #6

    GBR

    GBR

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