Lifting a Home on Slab Foundation

Thursday, July 27th, 2017 by Niles Erickson

Challenge

This lovely home just off Ocean Blvd. in Hampton, NH was built on a concrete slab, as full basements are not possible so close to the coastline. Over the years the slab was gradually settling, up to one inch or more towards the rear of the structure. The contractor did tell the homeowner there may be some settling, but one inch was more than expected. The rooms directly on the slab had laminate hardwood flooring, and the baseboard also had a round molding along the bottom, so that if some settling occurred, the molding would hide the gap. However, since the slab settled so much, the round molding was no longer able to hide the gap between the flooring and the baseboard, and the homeowner needed to address the issue promptly. There was clearly a void forming underneath the homes slab foundation, and a solution was needed to not only fill the void, but to also hopefully lift the concrete slab back to a level position. Another challenge, there was a radiant heat system built into the slab which helped keep the floor warm during the colder months. Whatever the solution was to be to lift the slab, it must be able to do so without damaging the heat system.

Solution

Erickson Foundation Supportworks inspected the homes foundation slab and the amount of settling, ultimately proposing to repair the slab with PolyLEVEL injection. PolyLEVEL polymer injection harnesses the expansive force of a structural grade geopolymer to provide fast concrete leveling, fill voids in soil and strengthen soil that has poor load-bearing qualities.

The first step before any drilling or injection could take place was to locate the radiant heat system within the floor, ensuring it would not be disturbed throughout the PolyLEVEL process. To do this, crew leader Andrew Ahlquist used a phone application which was able to register heat units and pinpoint where the system was located within the floor. Settling slab foundation

Once the radiant heat was located, the crew drilled through the floor and foundation and injected PolyLEVEL beneath the slab. The crew injected approximately 180 lbs of PL250, the common PolyLEVEL compound for most slab lifting projects. The lift required injection holes in 8 different locations, all towards the rear of the home. The slab lifted to a level position, and the PolyLEVEL process took no more than 3 hours to complete. The homeowner was thrilled with the results, and had to simply replace some flooring pieces and reinstall some round moulding along the bottom of the baseboard in two rooms.