Settling Home Addition, Londonderrry, NH

Challenge

This home in Londonderry, NH had an addition added 10 years ago to the rear of the garage, which became a workshop area, as well as a full master bedroom suite added above the garage. This extra space was going to be adding a lot of weight to the foundation system. When the addition was built, the homeowners had a contractor install some underpinning piers beneath the footings of the preexisting foundation of the garage, as it already had some cracks and required re-stabilization. Before installing the new foundation for the addition, the contractor brought in engineered fill and compacted the site well. However, this turned out to not be enough, and with the extra weight of the master suite up above the garage, the new foundation has settled, and the existing crack in the older, main foundation has also widened. The underpinning was a good idea, unfortunately though the piers were either not installed deep enough, or there were not enough of them installed.

Over the years, the foundation has cracked, shifted and settled. As the addition was attached to the main house, this was causing a concern as there was the potential for much damage to occur, resulting in the loss of value of the property. The homeowner was starting to notice cracks on the interior of the workshop space, and windows were also sticking. This corner of the structure had sunk up to and inch and a half, and something needed to be done to permanently stabilize the foundation before the situation got worse.

Solution

Erickson Foundation Supportworks inspected the foundation and existing cracks, proposing to use Push Piers to stabilize and lift the foundation. The home was sinking due to shrinking soils, and Push Piers would ensure the home could be permanently stabilized by reaching depths beneath the troubled soils. 

A total of ten Push Piers were installed, along the left hand side and the rear of the structure. Most of the piers reached depths up to 23', meaning the soils directly beneath the foundation were not suitable for supporting such a heavy load. After reaching more stable soils below, the piers were then attached to the foundations footings. The foundation was lifted with the Push Piers an inch and a half, bringing the structure close to level, and completely stabilizing it. This side of the home will no longer sink as the soil shrinks or moves. 

Additionally, the garage floor had also settled over the years, and homeowner also decided to address this issue. Once the Push Piers were installed and the foundation was backfilled, Erickson Foundation Supportworks brought in the PolyLEVEL rig and sprayed in an expanding, polymer foam beneath the slab where it was sinking. The garage slab lifted back to it's near original location, and the repair project was complete. With a 25 year warranty on the Push Piers, the homeowners can now get much more value for his property when they decide to sell.

Project Summary

Installing Contractor: Erickson Foundation Supportworks

Certified Inspector: John Prince

Crew Leader: Corey Chamberlain

Products Installed: Push Piers (8), PolyLEVEL