Slab Flatness Correction with Ardex Self-Leveling Underlayment
When a concrete slab sits outside tolerance, finish flooring cannot hide it. Ardex self-leveling underlayment corrects the slab plane so tile, plank, and polish install on a flat substrate. Portland Concrete applies the bonded primer system and pours to your finish-flooring spec. Free written estimate.
A slab that waves or dips cannot be corrected by the finish flooring itself. Tile, plank, and polished concrete all require a flat substrate to perform. If the slab is out of tolerance, the finish will telegraph the defect, and the installer will refuse the install or demand the slab be corrected first.
Ardex self-leveling underlayment is the engineered solution. The bonded primer adheres the new pour to the existing concrete, and the SLU material flows to a flat plane, correcting the slab elevation across the entire floor. We install as an Ardex-system contractor, meaning primer, mix ratio, pour technique, and cure schedule all follow Ardex spec, not a generic approach.
The result is a slab ready for the next trade. Coordinate with our Ardex repair mortars if spalls or cracks need patching first, and with our Ardex waterproofing if the slab sits below grade or in a wet zone.
Recent work
Installation sequence
Ardex SLU Installation in Portland
Laser-level the slab
We scan the existing slab with laser level, record elevation at grid points, and calculate the SLU depth needed at each zone to bring the floor to the finish-flooring tolerance spec.
Grind and apply primer
The slab surface is diamond-ground to Ardex profile, cleaned of dust and contaminants, and the matched Ardex primer is rolled across the entire area to create a permanent bond between the old concrete and the new SLU pour.
Mix, pour, and gauge
Ardex SLU is mixed to the exact water ratio specified by Ardex, poured across the floor in sections, and gauge-raked to the target elevation. The material self-levels to a flat plane within its working window.
Cure and verify flatness
The SLU cures on the Ardex schedule. Once cured, we verify the final flatness against the finish-flooring spec and hand off the slab to the tile, plank, or polish installer ready to proceed.
Scheduling and coordination
Planning Self-Leveling Into the Build
Ardex SLU works best when scheduled as part of the overall floor sequence, not as an emergency fix after the slab is already out of tolerance. We coordinate with the finish-flooring contractor (tile, plank, or polish installer) to agree on the target flatness, confirm the SLU depth and product choice, and schedule the pour into the build timeline.
Timing matters. Foot traffic can begin the same day or next, but finish-flooring install typically waits for the SLU to cure and dry to the finish spec. We provide the cure schedule and handoff documentation so the next trade knows when to start. Pair with our Ardex overlay systems if the goal is to leave the SLU as the finished floor itself, and with our full Ardex service range for any other slab prep or repair needs.
Bonded primer, tolerance specs, depth ranges and coordination with finish trades.
Ardex offers SLU products that can feather to extremely thin edges (essentially a few mil) and pour up to substantial depths for major tolerance correction. Product choice depends on the tolerance and project; we spec from the Ardex range.
Yes, critically. The Ardex primer is what bonds the SLU to the existing concrete. Without it, the SLU delaminates over time. Skipping or substituting the primer voids the Ardex system warranty.
Sometimes, with the matched Ardex polishable or top-coated overlay product. Most projects use SLU as substrate for tile, plank, or another finish; using it as the finish itself requires a different product spec.
Foot traffic typically the same day or next; finish-flooring install usually waits longer for the SLU to cure and dry to the finish spec. The cure schedule is in the project handoff.
Cost depends on depth, area, and existing slab condition. We provide a written quote based on the actual project; budget guidance can be discussed during the assessment.
Client reviews
What Portland Clients Say About Ardex Self-Leveling
They prep with Ardex primer like the spec calls for, not a generic primer. SLU bonds properly, my tile install goes in on a flat substrate. The Ardex-system difference is real.
Z. T5
Tile Contractor, Portland
★★★★★
Coordinated the SLU pour with my schedule, agreed the target tolerance up front, hit it on the pour. My plank install ran without complaint. Trade coordination at its best.
Y. T5
Finish Floor Installer, Vancouver
★★★★★
Three different substrate areas with different tolerance issues, three different Ardex SLU products specced. Each one matched the conditions; the finish-flooring went over each cleanly.
Q. T5
GC, Hillsboro
★★★★★
Tight feather-edge work at door thresholds where standard SLU would not work. They used the right Ardex product, feather edge held, no telegraph through the finish.
X. T5
Custom Home Builder, Gresham
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