Preparation sets the price. Square footage sets a floor under it. Two rooms of identical size can differ by several times over, depending on what is currently stuck to the slab and what condition the concrete underneath is in.
That’s why quotes vary so much, and why no honest contractor gives you a number over the phone. If you’d rather skip to a number for your own floor, request an estimate. Someone comes out to read the slab.
What follows is every variable that moves the figure, roughly in order of how much it moves it, and which of them you actually control rather than inherit.
The short version: the concrete decides most of it, and you decide the rest. Knowing which is which makes a quote far easier to read, and makes two competing quotes far easier to compare.
Why square footage is the wrong unit
Flooring is normally priced by area because most flooring is a product you buy by the roll or the box. More room, more material.
Polishing has almost no material cost, because the floor already exists. You’re buying machine hours, and those are governed by how much has to come off before the finishing work starts.
A 400 square foot garage carrying a failed coating routinely costs more than a 1,200 square foot living area under clean carpet. The garage needs that coating ground back to bare concrete first, and that’s the slow part. The living area needs the carpet lifted and the perimeter holes filled, which is an afternoon.
Anyone quoting from area alone is quoting the easy version, and they’ll revise it after they’ve seen the floor.
That’s the difference between a price and an estimate. A price implies the work is known. An estimate acknowledges that most of what decides the cost is currently hidden under something else.
What is currently on the slab
This is the largest single variable, and it’s entirely down to what previous owners chose.
Every layer over the concrete comes off mechanically, because solvents leave residue that interferes with how the densifier penetrates. Removal difficulty varies enormously between materials.
What is on the floor now | What removal involves | Effect on the job |
|---|---|---|
Bare or sealed slab | Nothing to remove | Shortest route |
Carpet and tack strip | Lift, fill perimeter holes | Small addition |
Vinyl or laminate | Lift, grind off adhesive | Moderate |
Tile | Break out, grind thinset | Significant |
Failed coating | Grind back to bare concrete | Significant |
Two or more generations | All of the above, in sequence | Largest single variable |
Layers compound. A house re-floored twice carries both generations, and the second removal only starts when the first finishes. That’s the situation behind most quotes people find surprising.
The age of the house predicts this better than anything else. A property from the fifties or sixties has had six decades of flooring decisions made on it, and it’s rare to find one that hasn’t been through at least two. A build from the last fifteen years has usually been through none.
The condition of the concrete itself
Once the slab is exposed, its own properties take over.
Hardness decides how many passes each grit stage needs. Soft concrete opens quickly and needs more care at the finishing stages. Hard, tightly troweled concrete resists the coarse tooling and takes longer to open at all. Neither is a fault. They’re just different amounts of machine time.
Flatness matters more than people expect. High spots have to come down before any consistent finish is possible, and on a badly poured floor that alone can double the coarse stage.
Cracking adds work in proportion to how much there is and whether it’s settled. Filling is quick. Working out which cracks are still moving takes a site visit, and filling one that hasn’t settled means filling it twice.
Previous patches grind differently from the concrete around them, so they show. That’s a conversation about expectations rather than a line item, but it affects what you’re buying.
The same applies to additions. Where a room was extended, concrete poured decades apart meets in the middle of a floor, and the two sides open differently under the grinder. It isn’t extra work exactly. It’s a limit on what a uniform finish can mean on that particular floor, and it should be established before the quote rather than after.
What the moisture reading changes
A slab with vapour moving through it doesn’t cost more to grind. It costs more to specify.
The reading changes which sealer suits the floor, and on a high result it can change the start date entirely, because a new pour that isn’t ready becomes ready with time rather than with product. That’s a scheduling cost rather than a materials one, and it’s real if you’ve got a fixed date.
It’s also the variable most often skipped, because testing properly takes about three days before any grinding starts. A contractor who hasn’t tested has removed three days from their timeline and transferred the risk to you.
We take an in-slab reading before quoting rather than after, which the moisture post covers properly.
What you decide, and what the slab decides
Almost everything above is inherited. You didn’t choose the pour, the previous flooring or the soil under the building. Two decisions are genuinely yours, and both move the price.
You decide | The slab decides |
|---|---|
Sheen level | What is currently on it |
Grinding depth | Concrete hardness and flatness |
Which rooms | Cracking and movement |
When it happens | Moisture reading |
Pour history |
Grinding depth is the bigger of the two. Stopping shallow for a cream finish means fewer passes through the coarse stages. Going deep enough to expose aggregate fully means more machine hours across the whole floor, and on a large area that’s a substantial difference.
Sheen costs less than people assume. The step from satin to high gloss is one or two extra fine grit stages, which is a smaller addition than the depth decision.
Worth knowing before you’re asked to choose: the two decisions are independent. A deeply ground floor can be matte, and a shallow cream finish can be high gloss. People often assume gloss means deep, and it doesn’t.
Access, layout and the shape of the room
Edge work is slower than field work. A large machine covers open floor quickly and can’t reach the last few inches against a wall, so perimeters get done with smaller equipment, and more perimeter means more hours on a floor of the same area.
So cut-up floor plans cost more per square foot than open ones. A 1,000 square foot open plan is faster than the same area split across five rooms with doorways, closets and a hallway.
Everything else is logistics. Stairs, tight parking, furniture that has to move, whether the power supply will run the equipment. None of it’s dramatic on its own and all of it is time. In parts of the city it’s a genuine factor: the Burnet Road corridor is under construction, and access along it is worse than usual.
Occupied buildings cost more than empty ones for the same reason. Working around furniture, sectioning a house so people can still live in it, or phasing a shop floor so it keeps trading all take longer than an empty space where the machines can run end to end.
What does not change the price much
Some things get charged for that shouldn’t be, and knowing which is useful when you’re comparing quotes.
Colour choice doesn’t affect it, because we don’t add colour at all. The floor is the concrete you’ve got, at the depth you choose.
Residential versus commercial doesn’t, in itself. A warehouse of comparable size and condition is similar work to a house. What differs is scheduling around a business, not the polishing.
Distance within the service area doesn’t, meaningfully. We block work by area where we can, so a Round Rock job isn’t priced differently from one in the city.
The brand of densifier doesn’t, and anyone leading with a product name is selling you something other than the outcome.
Why we publish no rate
Every page on this site declines to give a per-square-foot figure, and this is the post that explains why.
A published rate is only honest if it applies to a typical job, and there’s no typical job. The variables above range from an afternoon to a week on floors of the same size. A rate low enough to look competitive covers only the easiest version and gets revised upward after the site visit. A rate high enough to cover the hard version loses every straightforward job.
Contractors who publish one are quoting the first version. Worth remembering when a number online looks better than a number in person.
The same logic applies to instant online quote calculators. They ask for square footage and finish level, which are the two things that matter least, and they can’t ask about the things that matter most because you don’t know the answers yet either.
What a proper estimate involves
Someone stands on the floor. There’s no version of this that works from photographs, because the two largest variables, what’s bonded to the slab and what condition the concrete’s in, aren’t visible in an image.
What they should be checking: what’s currently down and how well it’s stuck, the hardness and flatness of the concrete underneath, cracking and whether it’s settled, coating history, and an in-slab moisture reading.
What you should get back: a figure, a realistic timeline, and a plain statement of anything on your particular floor that won’t polish out. If the third one’s missing, ask for it.
There’s more on what to ask a contractor before committing, including the questions that separate a specialist from a generalist.
Established 2012, working across Austin and Central Texas. Fully insured, no subcontractors, and estimates are free.
Call (512) 900-5938 or request an estimate, and we’ll read the slab before anyone commits to anything.