1

We're having a new foundation put under our garage. As the contractor removed the old slab, they placed 4x4s under the wall plates to support the garage while they worked. Now they are have placed the forms and it doesn't appear that there is a way (or the intention) to remove the 4x4s as the concrete goes in. It appears that the 4x4s, which are not pressure treated, will have about 1-2 inches of concrete between them and the sides of the foundation wall. At the bottom, they are touching bare earth, and at the top the plate sits on them.

My concerns are:

  • The 4x4s make it hard, maybe impossible, to place rebar in the foundation walls. Or at least to place it correctly.
  • The 4x4s were taken from my lumber stock and are quite dry (they are not pressure treated), could they "blow out" the sides of the wall as they get damp and expand?
  • They also seem to have the potential to become a termite haven, with one end sitting on bare dirt and the other in hard contact with the stud wall above.

I'd very much appreciate feedback on how real my concerns are, and if there are other potential issues. Right now I'm leaning pretty hard towards demanding that they be removed before the concrete is poured – if for no other reason than because that is what the crew said they were going to do and it "just doesn't seem right."

3

Do not let them pour concrete around (or against) non-treated wood, especially wood near the ground.

The Code requires wood in contact with concrete, masonry, or within 6” of ground shall be protected with pressure treated material in accordance with AWPA C22. (See ICC R402.1.2)

The Code establishes Termite Infestation Probability Map (See Figure R301.2(6).)

The Code requires “concrete and masonry foundation walls shall extend above the finish grade adjacent to the foundation a minimum of 4” (See ICC R404.1.6)

The Code also requires “slabs on ground shall have turn down footings with one #4 top and bottom of footing or slabs with stem walls shall have one #4 top and bottom of footing.” (See ICC R403.1.4.2)

Also the minimum depth of footing is 12” below finish grade. (See R403.1.5)

In addition, footings shall extend below the frost line specified in Table 301.2(1). (See R403..1.5.1)

In addition, anchor bolts shall be installed a minimum of 6’ apart and a maximum of 12” from corners and splices in sole plates, unless it’s located in a seismically active zone or high wind area. (See R403.1.8) Bolts shall be a minimum of 1/2” in diameter and extend a minimum of 7” into the concrete, unless located in a seismic area or high wind area.

There should be steel holddown anchors in the short walls on either side of the garage door opening for strength. The holddowns extend a minimum of 10” into the footings.

There are many issues with your project. (Using a 4x4 for a sole plate is acceptable, but it needs to be treated. )

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.