Winter-foundation

Discussion in 'Shop Talk' started by Rob30, Jan 21, 2005.

  1. Rob30

    Rob30 Well-Known Member Supporter

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    Location:
    Ontario
    For you people in the colder areas. Anybody have homes with shallow foundations? If so how do you stop the frost from heaving your house? I own a house with the foundation a little over 2 ft below grade. The frost in Ontario can go 3-4ft deep some years. I have a closed in porch at the entry which heaves a little. It throws the whole house out of whack. Paneling buckels, doors don't close right, etc. I can not remove the porch, it is part of the house, and I don't know if that corner of the house is to blame, I just think it it the porch.
    Any ideas?
     
  2. Cosmic

    Cosmic Well-Known Member

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    Location:
    Ohio
    Root cause probably is because that porch is not heated. In a normal house with a full foundation, the frost is not a problem because the heated zone goes out about two feet all the way around the house, frost can't act.

    You tend to get this problem in areas like attached garages on a slab that are not heated and they move in relation to the house.

    In your case, something like an air tight skirt all the way around the house, to include the porch might help. Apparently your house is able to radiant enough heat to the underside to prevent major frost action but the porch is sitting out by its lonesome and not receiving any of that heat on the underside. Anything you can do to extend the zone and allow some heat to conduct or migrate out to cover that zone will help. Once the frost is in the ground and acting, you are screwed. Normally the problem must be addressed in construction with a deep gravel bed layer to allow a place for movement, good plastic sheeting barriers to prevent moisture in the upper layers, etc. If it is just packed layered dirt is when the most severe problems occur. Covering the ground under your porch / house with a thick layer of dry leaves might be another approach to prevent the ground there freezing. Putting a plastic barrier under the leaves is even better. Is one trick used by graveyards to make exposed burial plots easy to dig in winter.

    One of my shed doors always used to jam due to frost heave. It is free standing and not heated. Only solution was to move the door to the other end. Repour a far thicker sill section much deeper and allow an expansion groove to accomodate the door. Either must prevent the movement or plan on a way to suck it up once it happens.
     

  3. Rob30

    Rob30 Well-Known Member Supporter

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    I actually was planning to get a little bit pf radiant heat into the porch. I am planning on surrounding the whole foundation with 2 inch insulation including the porch. I was thinking along the same lines. I didn't think of the plastic. I am also planting thick annual plants and mulch around the foundation to add insulative value. In northern Ontario there are mobile homes that sit on railroad ties for 20-30 years. They never move. I don't want to heat the porch, just capture the heat escaping out of the door and crawlspace.
    Thanks for your help, that will be yet another summer project.
     
  4. Buggs

    Buggs Member

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    Jan 23, 2005
    You need to dig a 2' x 2' trench around the shallow foundation and lay 2" rigid foam on the bottom and another 2" foam piece against the foundation wall. Search on the Internet for "shallow foundation" for more details