Before tile goes down, before plank floats, before polished concrete becomes the finish itself, the slab underneath has to be right. Laval Concrete pours new basement floor slabs for new builds and full replacements, each one set over a properly sealed vapor barrier, screeded flat, and handed back ready for whatever finish your project calls for. Free written estimate on every job.
Planning a Laval Basement Floor, What Gets Measured First
Every basement floor estimate starts with the same three questions: What is the subgrade condition? Is there an existing vapor barrier, and is it intact? What finish goes on top of the slab? Those answers determine the spec before a single yard of concrete is ordered.
Laval soil holds moisture year-round. A slab poured directly on damp subgrade without a sealed barrier will wick that moisture upward indefinitely, and no tile adhesive, floating plank, or epoxy coating survives that for long. Getting the barrier right at the seams is not optional prep work, it is the reason the finish above lasts. Where rigid foam underlayment is part of the spec (heated floors, for example), that layer goes in before the rebar or mesh, and the slab thickness is adjusted accordingly.
When the finish above will be polished concrete, the finishing pass on the slab itself changes. A floor destined for tile gets a different surface texture than one that will be ground and honed to a gloss. Knowing the end use before the pour is how both get done right. See our concrete cost guide for typical basement floor pricing, or check the residential floors page for finish options. Questions about slab thickness or mix design are covered in our concrete FAQs.
Recent work
How it works
From Subgrade to Finished Basement Slab, the Sequence
On-site measure and subgrade check
We measure the basement footprint, check the existing subgrade for soft spots or standing moisture, confirm plan elevation, and note any plumbing or radon rough-ins that need to be protected before work begins.
Subgrade prep and gravel base
The subgrade is graded and compacted to a consistent bearing surface. Crushed gravel is added where the spec calls for it, bringing the base to the correct elevation for the slab thickness and any underlayment layers above.
Vapor barrier, underlayment, and reinforcement
The vapor barrier is laid in overlapping sheets and taped at every seam so moisture has no path through. Rigid foam or other underlayment follows if specified, then rebar or wire mesh is set at the correct height within the slab depth.
Pour, screed, and finish to spec
Concrete is placed and screeded to a flat plane across the full basement floor. The finishing pass matches the end use: a smooth, tight surface for tile or floating plank, or a coarser open-aggregate surface if the slab will be ground and polished.
Control joints, cure protection, and handoff
Saw-cut control joints are placed on the schedule the slab requires. The surface is protected through the cure window, and the basement is handed back with written cure-time guidance so trades above know when it is safe to start.
Old slab failing? Here is how we approach it
Concrete Slab Replacement, Diagnosing the Laval Basement Floor Before the Pour
A cracked, heaved, or persistently wet basement floor is a symptom, not the problem itself. Pouring a new slab on top of an uncorrected cause, whether that is a missing barrier, a drainage issue along the footing, or subgrade settlement under one corner, produces a new slab with the same failure waiting to happen. The overlay approach has the same limitation: if the substrate is moving or wet, the overlay follows.
Laval Concrete looks at the cause before quoting the fix. Sometimes a targeted basement crack repair addresses an isolated problem without a full tear-out. Where the slab is sloped beyond correction, saturated from years without a barrier, or broken up from frost heave, a full replacement is the honest answer. The written quote will state which path applies and why, so there are no surprises when work starts.
Full replacement means breaking out the old concrete, removing the debris, correcting whatever caused the failure, and starting fresh with proper barrier and base. The new slab is poured to current spec, not to whatever the original contractor used decades ago. For homes where basement waterproofing is also needed, that work is coordinated so the drainage system and the new slab are installed in the right order. See the full range of basement concrete services for context on how the floor fits with the rest of the lower level.
New builds, replacement slabs, vapor barriers and finish-ready floors in Laval basements.
Yes, in Laval basements where the ground is consistently damp, a sealed vapor barrier under the slab is essential. Without it, moisture migrates up through the concrete for decades and ruins finishes on top, no matter how good the slab itself is.
Yes, polished basement floors are a real option here. We adjust the finishing pass, then grind, hone and polish the slab to the gloss level chosen, and the basement floor itself becomes the durable, low-maintenance finish.
Yes. Cracked or wet slabs almost always have an underlying cause, missing barrier, bad drainage, settlement. We diagnose it, fix that, then pour a new slab on the corrected base so the new floor does not inherit the old problem.
Most residential basement slabs are several inches thick over the prepared subgrade, reinforced with mesh or rebar. Exact thickness depends on the slab's use and the engineer's spec; the quote ties to your build.
You can usually walk on it within a day or two, but moisture testing should drive when finishes go on top. We hand back the slab with cure-time guidance so the tile, plank or carpet above does not get applied too early.
Homeowner reviews
What Laval Homeowners Say About Their Basement Floors
They flagged the missing vapor barrier under our old slab before quoting. Re-poured properly, sealed seams. Two springs in, the new floor is dry. Total game-changer for the basement.
Z. A.
Laval
★★★★★
Polished basement floor and it looks incredible. They adjusted the finishing pass for the polish, then ground and honed it themselves. One contractor, slab to shine.
Y. X.
Montreal
★★★★★
New build basement floor poured perfectly flat. The tile guys came in after and said it was the easiest install they had done all year. Their flatness call paid off.
Y. N.
Terrebonne
★★★★★
Tore out a slab that had been pouring wet for years. They found the source, fixed it, then poured a new one. Honest sequence, honest quote. Basement is finally usable.
W. D.
Longueuil
From the blog
Concrete Guides & Articles
Practical reading on planning, finishes and caring for concrete in Laval.
Let us know if you are pouring a new build slab, replacing a failed one, or planning a polished concrete finish. We measure the basement in person and send a written quote within one business day, no obligation.
