Foundation Build Procedure

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Tools and Supplies

  • Bobcat
  • Laser level
  • gravel
  • foundation forms - 2x10 lumber
  • rebar
  • rebar wire
  • Drill with 1/8" bit
  • Concrete - calling in a cement truck or get bags of concrete mix + cement mixer + water
  • Cement mixer, water hose, buckets for carrying concrete
  • 2x4 wood scree boards, 2' long
  • Measuring tape
  • wood forms
  • [40] wood stakes for fastening the foundation
  • 3" screws
  • [16] 1/2" rebar stakes, 2.5' long
  • Sill plate gasket (above foundation, below sill plate)
  • String
  • Level
  • Heavy hammer
  • Cutoff saw

Procedure - Stem Wall Foundation

  1. Level and clear the site with a bobcat or bulldozer.
  2. Grade the site such that the house is on a pad with drainage moving away from the house
  3. Use a laser level or string level so that the elevation is equal throughout the footprint of the house to +/- 1"
  4. Spread a truck load of 1/2" gravel for the foundation so that it is 6" thick
  5. Mark the 4 corners of the house at 16'1" (to accommodate 1/4" space between panels), roughly, such that the front of the house faces south
  6. Connect all corners with string so that the 16'1" distance is maintained.
  7. Adjust the 4 corners by declaring one side as fixed, then moving out the 16'1" length. Use string to fix the length at 16'1". Also use a string to connect the 2 adjusted corners, at 16'1"
  8. Measure the diagonals. If they are not equal, shift the 2 adjusting corners, maintaining the 16'1" distance between all sides
  9. Make sure the diagonals are equal +/- 1/4"
  10. This now marks the outer edge of the foundation. String marks the lines.
  11. For the inner edge of the foundation, begin by putting in more stakes
  12. Now the stakes are complete.

14. Set up a laser level so that you can mark the string level exactly, 9.5" above the gravel for the top of the 2x10. Adjust the string height on all stakes, for the outer and inner edge of the stem wall

15. Put your 2x10x16' lumber on the outer edge, using the string as your guide - keeping the 1/4" space under the string so the board does not interfere with the string.

16. Put in all the outside boards. Use a wooden stake every 4' to secure the boards. Use the heavy hammer to punch each stake in. Screw in the stake to the foundation forms, making sure not to move the form away from the straightness of the string.

17. Install the inner form boards. Make sure that the separation between the inner and outer form boards is 12" throughout. You can adjust the separation by controlling how deep you screw in the stakes - as you can use the screw to either close or open the space between the boards. For the inner boards, you need to trim the length slightly.

18. Once all boards are installed, drill the ends so you can install 2 sticks of 1/2" rebar down the middle of the form, 3" away from each edge and 6" away from each other. The rebar should be 4.5" up or in the middle of the boards in the vertical direction. Drill holes in the form ends to allow the rebar to protrude out so that it can be used for house additions.

19. Drill a 1/2" rebar hole in the forms at the midpoint of each side, so you can stick in a transverse supporting piece of rebar to support the lengthwise rebar - so the lengthwise rebar does not sag.

20. With the rebar in place, and sides all straight, the stake rebar and string can be removed, and we're ready for the pour.

21. As concrete fills the forms, scree the top smooth with a scree board.

22. Wait 24 hours and remove the concrete forms.

23. Trim the supporting rebar at the midpoints of the wall with an angle grinder.

The foundation is now ready for the walls.