Insulating my house with Roxul R15?? Enough??

Discussion in 'Insulation and Radiant Barriers' started by biddlecom, Sep 19, 2013.

  1. Sep 19, 2013 #1

    biddlecom

    biddlecom

    biddlecom

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    Hello, I am remodeling my house. I took down all the sheet rock and have bare walls now. The house has the siding then it has rigid foam board (not sure how thick but it looked decent - its blue if that matters) then I have the vapor barrier (I think that's what the plastic is) then its the diagonal wall boards then the 2x4 wall structure. The wall boards are slightly spaced from one another (photo below). Do I need to fill those gaps in some how? Also I want to use Roxul R15 in the walls would that be enough to keep my house warm in Maine? When I was pulling the old insulation out it looked pretty nasty and looked a little compressed and our house was still pretty warm. Also the idea was brought up to extend the exterior 2x4 to 2x6 but if I do that to the entire house it will take away sq footage but it will also allow me to put in Roxul R23. Is there anything else I should do? I dont know much about insulating but I do know I need to get it up before winter hits. Also heard something about interior vapor control? Whats that?

    Boards.jpg
     
  2. Sep 19, 2013 #2

    nealtw

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    In cold zones the vapour barrier should be on the inside but foam board is a vapour barrier and you do NOT want two. The wall needs to breath. You do not need to fill the gaps in the boards the siding and foamboard stops air movement there. You can check the depth to the exterior door frame depth. If the door frame is 6.5 inches you have 2" foam 5.5 inches you have 1" foam. All new houses have 2x6 walls for insulation so it would be a good idea, except bathroom where the toilet could be to close to out side wall or space becomes to small for tub. So you could do it where space allows. Your house may have been warm but the question is how much the heat cost. And welcome to the site.
     
  3. Sep 19, 2013 #3

    biddlecom

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    Thank you I'm glad to be here. I will indeed have many questions regrading home improvement.

    So the extra 2 inch of stud would probably be my best bet? I could do that in the entire house except the bathroom. So I have all the vapor protection I need and all I need to do is add some insulation and im good to go?
     
  4. Sep 19, 2013 #4

    bud16415

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    What kind of siding do you have. Chances are they did a house wrap and then the half inch fan fold foam. I believe that does not count as a vapor barrier? Others will know.

    More insulation is better and building the walls out by adding a 2x2 would work. Most of the time the electrical and window trims and all the openings etc will make it quite a job.

    As Neil said try and figure out what you have on the outside measure or pry up a piece of siding and get a look.
     
  5. Sep 19, 2013 #5

    biddlecom

    biddlecom

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    After looking it is a 1/2 inch fan fold. So I just need to know if I need another vapor barrier. Before I took the drywall down I didn't see any moisture issues.
     
  6. Sep 20, 2013 #6

    nealtw

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    My guess is that the insulation you took out had paper on the inside the paper would be the vapour barrier.. Your photo shows a nice clean wall, air leaking will be areas of very dirty insulation and framing. Where I am the vapour barrier is 6mil poly (sheet plastic) before drywall with special plastic boxes that go around outlets boxes , all joins in the poly are taped with red Tuck tap and the poly is sealed to the floor with acoustic sealer. The idea is, no air escapes from the house thru the walls.
     
  7. Sep 20, 2013 #7

    nealtw

    nealtw

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  8. Sep 20, 2013 #8

    biddlecom

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    So, I have my vinyl siding then 1/2 fan fold foam board then a house wrap. After that I have the house walls then I will be extending the 2x4 to 2x6 and placing Roxul R23 between the studs. Once that is done then I should put a 6mil plastic over the insulation and studs then put the drywall up???
     
  9. Sep 20, 2013 #9

    nealtw

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    Yes that is about it. But while you have it open you should be looking at other things that are done in new homes, like fire stopping. Look for holes
    that fire could get from a wall on one floor to a cavity on the next floor or attic and huicane hangers to the rafter is is cheap and not to much work.
     
  10. Sep 20, 2013 #10

    biddlecom

    biddlecom

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    The fire stopping is a good idea that I will look into and has far has hurricane hangers that is something we don't have to worry about in Maine. The worse we get is snow and cold.
     
  11. Sep 20, 2013 #11

    nealtw

    nealtw

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    They are only huricane hangers by name, they are to insure that there are enough nails in the rafters to prevent all kinds of problems and with climate changes who knows.
     
  12. Sep 21, 2013 #12

    GBR

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    The fan-fold (1/2") may have a perm rating of 1.1 Perms; http://www.google.com/url?sa=t&rct=j...52434380,d.cGE

    For your location, Zone 6; http://energycode.pnl.gov/EnergyCode...sp?state=Maine

    With over 1 perm at sheathing, you are vapor semi-permeable and require asphalt faced paper, SVR, or v.b. paint next to the drywall, Fig.4a: http://www.buildingscience.com/docum...nd-wall-design

    SVR; http://www.bestofbuildingscience.com...3-4_p37-40.pdf

    Don't use poly when a Class 2 will work; http://www.buildingscience.com/docu...heet-310-vapor-control-layer-recommendations/

    Been the same for many years; "A polyethylene vapor diffusion barrier and air barrier should only be
    used in
    very cold hygro-thermal regions. If it is used in other regions it reduces
    drying
    potentials to the interior more than it reduces wetting potentials from the
    interior." From; http://www.google.com/url?sa=t&sour...obC3Cw&usg=AFQjCNGKCc1gz_HCcZylkv71jEkZUZC98Q

    ADA the drywall; http://www.buildingscience.com/documents/information-sheets/air-barriers-airtight-drywall-approach/

    Gary
     
  13. Sep 21, 2013 #13

    nealtw

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    Gary: I stand corrected but some of your links don't work. Just to be clear, are you saying it is not required, or he should not do it?
     

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