Posted on March 20, 2014
Foundation Repair with Helical Piles
I bought a house. It was a GREAT deal! The reason I could afford so much property in such a great location is because the house has differential settlement. It was built in the 1950s. Mid-century ranch house on a sloping site with a walk-out basement at the rear. There was all sorts of speculation as to why the house was settling before I bought. One New Jersey Professional Engineer suggested that it was because of an addition added to the rear. Another soil engineer suggested the entire site was ‘fill’ and that was why. A third engineer attributed the problem to not enough leaders diverting rain water away from the front of the house.
The floor was noticeably out of level. Approximately four inches of settlement had occurred at the rear of the house only. I knew from previous experience that I could fix this, and about how much it was going to cost.
I developed a plan using helical piles installed from the inside of the basement to arrest further settlement and to provide deep foundation elements on which we could lift the rear wall of the house. The plan was to restore the first floor to a level condition.
The first step was to saw-cut the existing concrete basement slab and excavate soil to expose the existing footing. Visionary Construction was the general contractor for the job. After we exposed the footing, we found that the footing at the rear wall did not have sufficient depth. This was most likely the cause for the differential settlement. Visionary sub-contracted with Shore House Lifters, LLC. to install the helical piles and provide the lifting services. This company proved to be unreliable, and after starting the job, then delaying for over six weeks, finally admitted to not having the proper equipment to install the helical piles, and that they did not expect to lift the house.
Visionary Construction was able to find a replacement sub-contractor in Shore Earth Anchoring, (http://www.earthanchoring.com/) who not only had the equipment, but were also available to do the work quickly, and had a good price.
The helical piles were installed to the proper depth, torque, and in the correct locations. Hydraulic jacks are used to lift the wall. During the lift, there were cracks in wall finishes on the first floor and some doorways did not operate as they did before. Issues like this have to be expected when you are returning a house to a level condition. Anything that had been repaired while the house was uneven would now be subject to forces when the house was returned to a level and plumb condition.
I can not say that the house was returned to a perfectly level condition. We were able to lift about three inches. What we did do was to restore the floor to a condition where there is imperceptible unevenness. I also designed the helical piles with the capacity to support a future second floor addition.