The owner of this warehouse in Derry, New Hampshire contacted Erickson Foundation Supportworks when it noticed a section of the wall was cracking, sinking and falling apart. They installed some temporary posts to support the ceiling and roof of the structure, but were in need of serious support under the foundation before they could replace the cinder block wall, which needed to be dismantled before it crumbled and fell.
With the corner of the foundation settling and the wall collapsing with it, the owner removed the blocks on either side of the corner about 25 feet.
Upon excavating down to the footings of the foundation wall, the owner found there were large pieces of concrete tied to foundation wall. All this extra weight, combined with unstable soil, was most likely the cause of the corner of the foundation settling. The extra concrete buried around the foundation also made it a difficult, long process for excavation, as they had to use jack hammers along with the excavator in order to break through and expose the footings.
Erickson Foundation Supportworks proposed installing four (4) helical piers, two on either side of the corner, to stabilize the foundation and prevent it from settling any further. With the foundation permanently stabilized, no actual lift would be required for this structure, and so the owner could rebuild the wall above afterwards. Lifting the foundation came with the risk of doing further damage to the cinder block wall of the warehouse, and so it was not recommended in this case.
In order to reach load bearing soils for this structure, the helical piers were installed up to depths of 40 feet each. Once the piers were pushed down, they were capped off and attached to the footing of the foundation. At these depths, the piers permanently stabilized the structure and will prevent it from settling any further.
Installation of the helical piers took one day, and the owner decided to take care of all excavation and back fill responsibilities himself.
Installing Contractor: Erickson Foundation Supportworks
Products Installed: Four (4) Helical Piers
Crew Leader: Andrew Ahlquist