Polish the slab or coat it, and why the concrete usually decides for you

A coating is an added material. Epoxy or polyaspartic goes down as a liquid, bonds to the prepared concrete and cures into a film that sits on top of the slab. What you walk on afterwards is the coating, and the concrete underneath is a substrate you never see again.

Polishing is subtraction. The slab is ground with progressively finer diamond tooling, treated with a chemical densifier that hardens the surface layer, and then refined until it reflects light. Nothing is added except the densifier and a sealer that soaks in. What you walk on afterwards is the concrete itself, in the condition the grinding revealed.

That difference is the whole decision, and it cuts both ways. A coating gives you a colour, a flake pattern or a metallic effect, and it covers a slab that has patch marks, colour variation and old adhesive shadows. Polishing gives you a surface that cannot peel, because there is no film to lose adhesion, but it shows you the slab you actually own, including the parts of it nobody looked at when the house or the unit was built.

Armour Guard puts the base cost at $3 to $12 per square foot to polish existing concrete in the Greater Toronto Area, and $10 to $25 or more per square foot where a new concrete pour is required first. That gap is the single most useful number in this article, because it means the first question is not what finish you want but whether the slab you have can be polished at all.

Within the existing slab band, the finish level drives the price. Armour Guard separates a basic grind and seal finish at $3 to $6 per square foot from a high gloss polished finish at $8 to $15. The same source prices decorative work such as staining, scoring or exposing the aggregate at another $2 to $10 per square foot on top.

Other GTA sources land in the same territory by a different route. Toronto Concrete Repairs prices residential polished concrete at $6 to $12 per square foot, commercial at $4 to $10 and industrial at $3 to $8. ConcreteYourWay prices residential at $6 to $12 and commercial at $3 to $8. VMB Group prices concrete polishing in Toronto at $4 to $8, and Epoxy Flooring Toronto at $4 to $10. The agreement across those sources is closer than anything published for coatings, which is worth something on its own.

A polished floor is not one pass. The crew starts with coarse metal bonded diamonds to take the surface down past whatever is on it and to flatten the slab, then steps through progressively finer tooling. Somewhere in the middle of that sequence a chemical densifier is applied, which reacts inside the concrete and hardens the surface so the finer passes can bring up a shine rather than just polishing soft cement paste.

The number of passes is what separates a grind and seal from a high gloss floor, and it is why the two sit at different ends of Armour Guard's price range. A grind and seal stops early, flattens the surface, and gets its sheen from a topical sealer. A high gloss floor keeps going through the fine grits until the concrete itself is reflective.

How far the first pass has to cut is the part nobody can quote from a photograph. Old adhesive, a thin skim coat, or a slab that was power trowelled hard will each change how many passes it takes to reach a consistent surface, and the aggregate exposure you end up with depends on how deep the crew had to go.

Toronto slabs are old, and freeze and thaw cycling has been working on them for decades. Armour Guard notes that cracks and surface damage from freeze and thaw can add $1 to $5 per square foot in extra preparation, and that older homes in neighbourhoods such as Leslieville, Riverdale and East York often have concrete needing substantial repair before polishing.

Repairs are visible in a polished floor in a way they are not under a coating. A crack that has been stitched and filled reads as a line across the finished surface. A patch reads as a patch. For some rooms that is character and for others it is a defect, and only you can say which, but the decision has to be made before the grinder starts rather than after.

Below grade adds its own condition. Armour Guard prices a moisture barrier for below grade installations at $2 to $4 per square foot and a sound control underlayment for condos and multi unit buildings at $1 to $3. Armour Guard also prices integrating hydronic radiant heating with a polished floor at $6 to $12 per square foot. Toronto building codes and permit requirements can also add cost on new pour projects, particularly in heritage properties, according to the same source.

Armour Guard publishes two named GTA projects rather than generic estimates, and they are the clearest illustration of how far the range stretches in practice.

The first is a 2,200 square foot century home in Riverdale involving crack repair, levelling and a medium polish with staining. That project came to $28,600, which the source itself works out as $13 per square foot. The second is a 3,800 square foot retail space in Liberty Village that needed tile removal, a new concrete pour, a high gloss polish and a logo integrated into the floor. That came to $72,200, or $19 per square foot.

Both of those sit above the headline $3 to $12 band, and neither is an outlier. They are what happens when the slab needs work first, which in older Toronto stock is the normal case rather than the exception. Treat the low end of any published range as the price of a floor that is already flat, sound and clean.

This index lists 221 floor coating companies in the Greater Toronto Area. Of those, 207 are recorded in the epoxy and garage floor coating category and 40 are recorded as doing polished and sealed concrete. The overlap is the useful part: 38 of the 40 polishing companies are recorded in both, which means most firms in this market can quote you either finish and are not structurally committed to selling you one.

That also means the recommendation you get is worth listening to, and worth testing. If a contractor who does both looks at your slab and says polishing will expose more than you want to see, that is an opinion with nothing riding on it. If a contractor who only coats says the same thing, it is still probably true, but you have less information about why.

What no listing on this site can tell you is which firms hold which polishing equipment, how many passes they include as standard, or what a finished floor of theirs looks like. Ask to see a polished floor they finished at least a couple of years ago, in a building of similar age to yours. A polished slab does not fail the way a coating fails, but it does show its history, and history is exactly what an old Toronto slab has plenty of.