GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

I am rebuilding a house and the sill plate is below grade

9woodworks9 | Posted in Green Building Techniques on

I am putting new ZIP sheathing over the whole house but 10 inches is below grade. I was thinking of putting Durock below grade for the 10 inches but some say pressure treated plywood might be better? Either product will be treated with a waterproof coating and then 3 inches of rigid foam then a stone exterior which is best or can I use something else? The foundation is block they just build it below grade …

Thanks

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.

Replies

  1. GBA Editor
    Martin Holladay | | #1

    Michael,
    You've got a major problem on your hands.

    The correct solution is to lower the grade by at least 18 inches.

    If circumstances don't allow you to lower the grade, you should hire a house-moving company to jack up the house so that the foundation can be raised 18 inches.

  2. 9woodworks9 | | #2

    Thanks but that's not going to be an option of house raising. The house is 24 years old and only one spot has rot from improper grade sloping to the house. I have 2 inches of insulated R 10 drain board which should carry any water load to the base of the basement wall. I know they build homes of pressure treated wood foundations..not good but I still need an option ?

  3. GBA Editor
    Martin Holladay | | #3

    Michael,
    Can you lower the grade?

  4. 9woodworks9 | | #4

    No I can not lower the grade... They make a PVC panel as well very expensive but not sure how well that might work ?

  5. GBA Editor
    Martin Holladay | | #5

    Michael,
    It's one thing to engineer an All-Wood Foundation on a new house, using pressure treated lumber, pressure-treated plywood, stainless-steel fasteners, many truckloads of below-grade crushed stone, and a well-engineered underground drainage system.

    Trying to solve a problem with a 24-year-old house that has been mistakenly backfilled 10 inches above the sill is an entirely different matter.

    I think you are making a mistake. I advise you to lower the grade or jack up the house.

  6. 9woodworks9 | | #6

    thanks for your help ....

  7. DRKdesign | | #7

    Michael
    Why not just build a retaining wall to stop the soil just short of the wall, creating a space between the wall and the soil. That way you do not have to worry about the potential of any wood-to-ground contact.

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |