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  1. #1
    Join Date
    Feb 2014
    Location
    north texas
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    3

    Default exterior insulation : Wrap or no Wrap

    I have an old 1880's wood siding home in North Texas. I need to replace much of the siding on it. There is controversy on old homes about insulating walls due to moisture escape issues. The walls are no longer plaster but do have the ship lap on the interior side of the stud. What does any one think about insulating walls in this part of the country? Also the exterior siding is connected to the 2x6 directly with no outer ship lap. If I remove the siding, the interior wall in there,(that is ship lapped). Should I house wrap directly to the studs and then side it or leave it open? So in short insulate or not and wrap or not?

    Thanks for any insight,
    The Baker

  2. #2
    Join Date
    Dec 2007
    Location
    Tennessee
    Posts
    1,769

    Default Re: exterior insulation : Wrap or no Wrap

    My biggest concern with removing the exterior siding is that the house could possibly rack on you. If the exterior siding is some type of 4x8 plywood, it could be the only thing keeping the house from falling over. First confirm that the framing has some diagonal members to keep the house from racking.

    Insulation is always good as long as it is installed correctly. You should take off the shiplap inside, used faced batts or unfaced batts with a separate vapor barrier. Install diagonal members in the framing to prevent racking, then reapply the interior shiplap. Note: if the shiplap is installed on a diagonal, it may be the racking control so you will need to leave a couple boards up at all times.

    You could use a closed cell foam with the exterior off and not bother with all the rest if you want. That might be the easiest way to go.

  3. #3
    Join Date
    Dec 2010
    Location
    Houston Texas
    Posts
    2,969

    Default Re: exterior insulation : Wrap or no Wrap

    Just how far north?

    Normally we put the house wrap on the side where the warmer air is. In South Texas we put the house wrap on the outside with no vapor barrier on the inside. Northern climates that heat more than cool the interiors put the vapor barrier on the inside.

  4. #4
    Join Date
    Feb 2014
    Location
    north texas
    Posts
    3

    Default Re: exterior insulation : Wrap or no Wrap

    Quote Originally Posted by keith3267 View Post
    My biggest concern with removing the exterior siding is that the house could possibly rack on you. If the exterior siding is some type of 4x8 plywood, it could be the only thing keeping the house from falling over. First confirm that the framing has some diagonal members to keep the house from racking.

    Insulation is always good as long as it is installed correctly. You should take off the shiplap inside, used faced batts or unfaced batts with a separate vapor barrier. Install diagonal members in the framing to prevent racking, then reapply the interior shiplap. Note: if the shiplap is installed on a diagonal, it may be the racking control so you will need to leave a couple boards up at all times.

    You could use a closed cell foam with the exterior off and not bother with all the rest if you want. That might be the easiest way to go.
    i know there is cross bracing from a small section I have done. thanks for the reply.

  5. #5
    Join Date
    Feb 2014
    Location
    north texas
    Posts
    3

    Default Re: exterior insulation : Wrap or no Wrap

    Quote Originally Posted by HoustonRemodeler View Post
    Just how far north?

    Normally we put the house wrap on the side where the warmer air is. In South Texas we put the house wrap on the outside with no vapor barrier on the inside. Northern climates that heat more than cool the interiors put the vapor barrier on the inside.
    I am north of d/fw about 40 minutes. I don't know if they use vapor barrier in this area.?

  6. #6
    Join Date
    Dec 2007
    Location
    Tennessee
    Posts
    1,769

    Default Re: exterior insulation : Wrap or no Wrap

    House wrap is not a vapor barrier so it goes on the outside in ALL climates. House wrap is a wind barrier, it allows vapor to escape from inside the wall cavity and prevents liquid water from entering the wall cavity, but water vapor will travel through house wrap in either direction, going from the higher relative humidity (RH) to the lower RH.

    A vapor barrier goes on the inside, toward the interior in all but a very few locations in this country. In those area where the vapor barrier does not go on the inside, it is better to just use house wrap and no vapor barrier at all. You are not in one of those locations.

  7. #7
    Join Date
    Jan 2014
    Location
    NH
    Posts
    136

    Default Re: exterior insulation : Wrap or no Wrap

    Hi, I would use a paper wrap inside and out. Plastic may be good for plants in a greenhouse but it shouldn't be used in a living space for people. Thanks

  8. #8
    Join Date
    Dec 2010
    Location
    Houston Texas
    Posts
    2,969

    Default Re: exterior insulation : Wrap or no Wrap

    What the folks from Dupont have to say http://www.dupont.com/products-and-s...ouse-wrap.html

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