Flat Slabs Ready for Finish Flooring with Ardex Self-Leveling
When a concrete slab sits out of tolerance, finish flooring cannot hide it. Ardex self-leveling underlayment corrects the slab plane so tile, plank, and polish install on a true, flat substrate. We pour Ardex SLU as a certified system installer, bonding the new layer to the existing concrete with Ardex primer and engineered chemistry. Free written estimate.
A slab that waves or dips cannot be fixed by the finish flooring itself. Tile grout lines will follow the slab undulation, plank will rock, and polish will highlight every low spot. The slab tolerance must be corrected before the finish goes down. That is what Ardex self-leveling underlayment does: it fills the low spots and brings the entire slab plane to the flatness the finish flooring spec requires.
We install Ardex SLU following the full Ardex system protocol. The existing slab is prepped to Ardex profile, the matched Ardex primer is applied to bond the new pour to the old concrete, and the SLU is mixed and poured to self-level to the target plane. The result is a substrate ready for the next trade. See our full Ardex service range if the project also needs overlay, repair, or waterproofing work.
This approach differs from generic self-leveling products because the Ardex system includes the primer bond, the product chemistry, and the installer certification. Coordinate with our residential floor prep service or our heavy-duty industrial flooring work if the project scope is broader.
Recent work
Installation sequence
How Ardex SLU Gets Installed in Boston
Measure slab elevation across the floor
We laser-scan or manually map the existing slab to identify high and low spots, calculate the depth of SLU needed to bring the slab to the finish-flooring tolerance spec, and confirm the plan with the tile or plank installer.
Prep and prime the concrete
The slab surface is diamond-ground to Ardex profile, cleaned of dust and contaminants, and the Ardex primer is rolled across the entire area. The primer is what creates the permanent bond between the old slab and the new SLU layer.
Mix, pour, and gauge-rake
Ardex SLU is mixed to the manufacturer water ratio, poured across the floor in sections, and gauge-raked to a consistent depth. The material self-levels to a flat plane within its working time window.
Cure to finish-ready and hand off
The SLU cures on the Ardex schedule. Once cured, the final flatness is verified against the finish spec, and the slab is handed to the tile, plank, or polish installer ready for the next phase.
Scheduling and coordination
Planning Self-Leveling Into the Build
Ardex SLU works best when scheduled as part of the build sequence, not added as a last-minute fix. We coordinate the pour timing with the finish-flooring contractor, agree on the target flatness up front, and execute to that spec so the next trade's install runs without surprises.
If the project also needs Ardex overlay or waterproofing systems, we can spec those into the same Ardex protocol. Reach out to discuss how Ardex repair mortars fit if the slab has cracks or spalls that need addressing before the SLU goes down.
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.
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, Boston
★★★★★
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, Cambridge
★★★★★
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, Somerville
★★★★★
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, Quincy
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