Low pitched roof insulation

Discussion in 'Insulation and Radiant Barriers' started by MATREDGT, Feb 2, 2018.

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  1. Feb 2, 2018 #1

    MATREDGT

    MATREDGT

    MATREDGT

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    I'm trying to determine the best way to go about insulating my attic. I am very DIY oriented and hate spending extra to pay someone to perform a task. I'd rather learn through trial and error and come out having learned something.

    I have a low pitched hip roof with traditional rafters (probably a 3-12 pitch). The ceiling joist's are 2x6's and the roof joist's are 2x6's which leaves me with 5.5 inches at the top plate for insulation. The house was built in '71 and it appears to have about an R-11 or so in the attic. At some point someone added a layer of Owens Corning Miraflex insulation, which I've found to be rated at R-25. Now they didn't stuff the Miraflex down to the top plates, so there is at least a 3' gap around the entire perimeter of the house that only has the original layer of insulation. It doesn't fill the void of the top plate as I can see daylight from the soffit vents.

    Currently there aren't any soffit vent baffles installed, so that would be my first step. I'm still unsure how many of those to install, but regardless where they are installed that will only leave me with about 4.5" of space above my top plate. I live in Michigan (zone 5), so R-38 is the minimum recommended amount of attic insulation. Obviously the only insulation that could achieve near this is spray foam. I have been researching the DIY spray foam kits and the results seem hit or miss at best. I am a large guy (6'6" and a bit portly) so getting myself down to the eaves to seal them with spray foam, while moving fast enough that the foam gun doesn't plug, will prove difficult.

    So I am considering a couple options. Hire someone to spray foam at the top plate to a point where I can start fiberglass batts and ultimately top with blown in cellulose. Now depending on costs or ease this option may cause me to pull down all of the soffit vents for access from the outside of the house.

    I could also DIY the spray foam, but I'm an electrician that works outside so spring is the kick off to my busy season. From April to November I usually am working 6 days a week.

    Another option is to remove the original fiberglass and replace with an R-19 out over the top plate. Then use blown in cellulose to get me to an R-48 or R-60. I know that over the top plate I would be way below what is recommended, but it would be much better than it is now.

    Ultimately cost will play a huge factor in my decision but I am really looking for some other opinions on the matter. I don't see myself in this house for more than 5 more years, but I am not one to do things half as**d like the previous homeowner did.


    Thank you for any input
     
  2. Feb 2, 2018 #2

    nealtw

    nealtw

    nealtw

    Contractor retired

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    Air chute in every bay. Use pieces of that old insulation like about a foot bent over a flat tool like a window squeegee you can push it to just over the wall and it will hold the chute in place and block the hole to stop loose insulation from going out into the soffet. All you need.
     
    mudmixer likes this.

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