No announcement yet.

existing foundation has no footing

  • Filter
  • Time
  • Show
Clear All
new posts

  • existing foundation has no footing

    Iam planning a renovation to my 45 year old bungallow which will entail adding a second story. The existing concrete foundation wall does not have a footing and frankly is not high enough to provide an adequate ceiling height in the basement. I am looking for suggestions as to how i may install a concrete footing under the existing concrete foundation wall in order to support the load of a second story?

  • #2
    Re: existing foundation has no footing

    Hi Barry:
    I would begin by talking to an engineer to design and calc the project. There are many variables, and it's not a project to tackle if you haven't dealt with underpinning before.

    Hope this helps



    • #3
      Re: existing foundation has no footing

      I have done this type of retrofit before, but it makes me a little nervous to recommend it in a forum. The disclaimer: CONSULT WITH AN ENGINEER!

      If you have a good stable base inside the basement/crawlspace – build a temporary wall about 2-feet away from the inside face of the existing foundation wall to support the current structure. You can angle the wall a bit to get more room at the base. It is ideal if you position the top of the temporary wall as close as possible to the wall. Next trench around the outside of the foundation along one side at a time. Dig down to a level that you want the bottom of the footing to rest on. Dig under the existing foundation wall by hand in small sections. I would recommend digging alternating sections that are ~4-feet long. That is, dig a 4-foot section then leave 4-feet of undisturbed soil and then repeat with a 4-foot dug section and then another 4-foot undisturbed section until you reach the end of the wall’s length. Form up the sections and pour concrete footings in the dug sections so that the top of the pour rises a bit higher than the bottom of the wall so that you are sure you make full contact along the base. Once the concrete has set up, repeat the process for the previously undisturbed sections of footing. This method is conservative, since you have a full temporary wall and half the foundation wall supporting the load of one side of the house at a time. It also allows you to have good access from inside and outside for digging. It also allows you to moisture proof the foundation and adds good drainage. This is a serious upgrade. Be careful. Be patient.