Moisture and evidence of past water
Damp patches, efflorescence and staining, plus whether the product being considered calls for an actual moisture test rather than a visual check.
What gets recorded on a slab before we quote it
A scope that skips the concrete is a guess wearing a number.
Flatness across the whole plane
High and low points measured across the full slab instead of room by room, because a slab that has moved does not respect the walls that were built on top of it.
Cracks, width and vertical offset
Crack width matters less than whether the two sides still sit level with each other. A lip means something moved, and it shortens the list of finishes that will work over it.
Penetrations and service access
Floor drains, sump lids, cleanouts and any radon rough-in located first, so nothing that needs reaching later ends up buried under a finished floor.
Finished height
Membrane, panel, underlay and finish thickness added together and checked against ceiling height, door swings and the bottom stair riser before anything is ordered.
Planning ranges for slab preparation and finish
Canadian dollars, for early budgeting only. Levelling is the line that moves most, because the quantity of compound depends entirely on how far out of flat the slab actually is.
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Floor levelling
$2 to $6 per sq ft
Site-wide planning range for levelling and self-levelling compound. On a heaved slab this is a real cost line rather than a rounding error, and it is quoted separately for that reason.
Vinyl and LVP installation
$4 to $9 per sq ft
Site-wide planning range for vinyl and luxury vinyl plank over a prepared slab. Rigid-core products bridge minor surface texture but do not correct a slab that has moved.
Tile supply and installation
$8 to $25 per sq ft
Site-wide planning range for tile. Tile is the least forgiving finish over a slab that is still working, so the preparation standard in front of it is higher.
Flooring Experts Calgary provides flooring installation and repair to homeowners and businesses across Indus, Alberta.
Expansive clay reaches the slab before it reaches the footings
Indus sits in open country close to Calgary's eastern edge, and the ground under this whole region is the reason basement floors get their own conversation.
Expansive, shrink-swell clay is widespread across Alberta. It takes on water and swells, dries out and contracts, and it does not do either evenly. Forensic engineering sources on expansive soils make a point that surprises most homeowners: basement floor slabs are affected by that movement to a far greater degree than footings are, which is why a heaved or cracked slab is a much more ordinary finding than actual foundation damage.
The practical consequence is that a basement can look entirely normal and still be out of flat by a noticeable amount from one corner to the other. It is also why we survey the whole slab plane rather than the room being finished. A slab does not stop moving at a partition wall that was framed on top of it.
Grinding, filling and the line item nobody budgets for
Once the plane is mapped, the preparation splits into two jobs.
High points get ground back. Low areas get filled with self-levelling compound. Which of the two dominates depends on where the concrete has actually moved, and a large open area that has lifted in the middle often needs both. The quantity of compound is what makes this a real cost line, not a rounding error, and it is the single most common reason a floor quote changes after someone has looked at the slab.
Crack assessment runs alongside it but answers a different question. Width is less important than whether the two sides still sit level with each other. A tight, stable crack with no vertical offset is a preparation item and nothing more. A crack with a lip tells you something moved, and it narrows what can sensibly go over it. Rigid plank tolerates a little of this. Tile tolerates almost none.
We quote levelling as its own line for exactly that reason. Folded into a per-square-foot figure it becomes invisible, and invisible costs are the ones that turn into arguments.
Anything that penetrates the concrete happens first
The last part is sequencing, and it costs nothing except a conversation in the right week.
Health Canada's radon action level is 200 Bq/m3. Where a property tests at or above it, mitigation normally means work at the slab: a core for sub-slab depressurization, plus sealing of cracks, the sump lid and other openings. We do not test for radon and we do not install mitigation systems. What we can do is make sure that work, if it is coming, happens before the finished floor rather than after it.
The same logic covers drainage work, plumbing under the slab and any framing that has to be fastened through the concrete. Get everything that penetrates the slab finished, then floor it once. Cutting into a new floor to reach the concrete underneath is entirely avoidable.
Slab and levelling questions on Indus properties
Why is the basement slab cracked when the foundation looks fine?
Because they are not the same thing. Expansive, shrink-swell clay is widespread across Alberta, and forensic engineering sources on these soils note that basement floor slabs are affected by clay movement to a far greater degree than footings are. Heaved and cracked slabs are a much more common finding than genuine foundation damage.
Can vinyl plank go straight onto the slab?
Often yes, provided the slab is clean, sound, dry enough for that product and inside the flatness tolerance written into the manufacturer's instructions. Rigid-core plank bridges small surface texture. It does not correct a slab that has heaved or is still moving, and pretending otherwise just moves the problem to the surface later.
How do I tell whether levelling will be needed before you arrive?
A long straight edge or a level laid across the floor in several directions will show you most of it. Rocking, daylight under the edge or a marble that consistently rolls the same way are all worth mentioning. It will not replace a proper survey, but it tells us what to expect.
Will a new floor do anything about radon?
No. Health Canada sets a radon action level of 200 Bq/m3, and testing and mitigation are separate work carried out by a different trade, not by us. It matters to flooring only for sequencing, because mitigation involves coring the slab and sealing openings, and that should happen before a finished floor goes down.
What if the slab is still moving?
Then we say so, and the list of workable finishes gets shorter rather than longer. A tight, stable crack with both sides level is a preparation item. A crack with a lip is a movement problem, and tile is the least tolerant thing you can put over one.