Lifting a radiant heated concrete floor with Precision Lift
Contractor: Manicured Concrete Solutions, Edmonton, Alberta
Client: Private homeowner, Edmonton
Problem: Manicured Concrete Solutions was called in to lift the basement floor of a home high on the banks of the North Saskatchewan River in Edmonton. The floor is a floating concrete slab with hardwood on top of it. Inside the slab are radiant heating elements. An approximately 33’ (10m) section of the basement had settled ½” to ¾” (1.5-2 cm) from the baseboard. The floor needed to be lifted back into a level position.
Solution: Manicured Concrete Solutions uses the Prime Resins Revolution compact slab lifting system to fill voids and lift concrete with Precision Lift polyurethane structural foam. Foam is injected through dime-sized holes drilled through the concrete. Owner Richard Ross brought the Revolution into the basement to do the lifting. The unit is designed to fit through a standard doorway, making it the only truly portable system on the market.
Challenge: Given the radiant heat system embedded in the floor, injection hole placement was crucial. “The biggest concern was making sure we didn’t hit the in-floor heating, says Ross. “We used a reliable, experienced third party to survey the floor with ground penetrating radar and thermal imaging to ensure we could identify where all the lines were located.” Given the complexity of the situation, Ross engaged on-site technical support from Prime Resins.
Process:
- Ross marked the grid of the hole pattern on the floor.
- After the holes were drilled, they used fiberglass probes to assess the voids. The GPR identified the area of the void, but couldn’t tell the precise dimensions because the wire mesh and the heating elements inside the concrete obstructed the readings. There was a 2-6” (5-15 cm) void below the concrete. It appears that melting snow and rain are migrating under the house, which the homeowner will need to address to avoid further erosion.
- Next they assessed the soil conditions, which turned out to be very soft. The substrate is so soft that the probes could be hand-pushed into the ground 24-30” (61-76cm).
- Ross injected Precision Lift 2135 through the drill holes.
The heating elements were marked and probes were used to assess voids and soil conditions. Note how deep the far left probe could be pushed. Image copyright Prime Resins, Inc. Re-use not permitted.
Precision Lift 2135 is injected with the Equalizer gun; lift is monitored with the gauge on the windowsill. Image copyright Prime Resins, Inc. Re-use not permitted.
Outcome: The polyurethane foam compacted the soil, filled the void and successfully lifted the floor back to level. Prior to the GPR and thermal imaging, the hardwood floors had been removed. The homeowner will leave the floor bare for some time in order to monitor the conditions. The radiant heat system had been running for weeks, so the substrate was not frozen, but the ground could settle further. The foam itself will remain intact with no shrinkage, but the ground could settle with the spring thaw and the erosion issues. If further settling occurs, MCS will return to address the problem.
“My biggest fear from a slab raising perspective was that the slab would bind and the homeowner would not have a level floor. Fortunately the job went very well and the homeowner now has a level floor. I was very happy with the outcome of this project,” says Ross.