Polished concrete questions answered in plain English

Most floors are €90 to €150 a m². Large floors with a standard finish start at €55 to €60 a m²; small floors and high-end finishes start at €120 a m². Rural jobs add €20 to €30 a m². See our price guide.

Often, yes, and then the grinding and polishing is the whole cost. Whether yours polishes well depends on the concrete, what's been stuck to it and the cracks. A test grind shows it. See polishing an existing floor.

A new slab cures for at least 28 days before the grinding starts. The polishing itself takes days, not weeks, depending on the size and the finish. How long it takes.

The machines grind wet or with dust extraction, so ask which. On a new build it's done before the kitchen goes in. In a lived-in house the room has to be empty for the days it takes.

Very well. The pipes go in the slab, and the concrete holds and releases the heat slowly. Keep the water no hotter than 35°C and run it low all the time. See underfloor heating.

It feels cool without heating, which is why most new polished floors in houses go over underfloor heating. Dry, it's as slip resistant as polished marble, granite or porcelain; for an R10 rating it needs a slip resistant coating.

Ask for it in writing with the price: what's covered, for how long, and how cracks are treated. Concrete can crack as it dries, months or years after the floor is laid, and joints in the right places give it somewhere to crack neatly.

One polished concrete contractor that covers your county. They ring within one working day, look at the floor or the drawings, price it in writing and deal with you directly.

Specify a minimum C35/40 strength class (or C32/40 with low water-cement ratio around 0.45), nominal 10 mm or 20 mm local limestone or granite aggregate, minimal or carefully controlled GGBS content to avoid dark blue-grey mottling once dried, and poly-fibre reinforcement matched with weld-mesh so fibres do not fur during grinding.

Large three-head planetary grinders stop roughly 50–75 mm shy of perimeter walls, door frames, and kitchen islands. A dedicated hand-edging crew follows behind with 125 mm shroud-mounted diamond hand grinders and corner detail sanders through the exact same grit progression so the perimeter matches the main field.

All cement slabs shrink slightly as they cure and cycle thermally, so hairline shrinkage relief is managed through saw-cut control joints placed every 3.5 to 4.5 metres across doorways and column lines, filled flush with colour-matched flexible polyurea joint sealant after grinding.

Mechanically polished concrete uses a 7- to 9-step metal and resin diamond grit progression plus a penetrating chemical densifier so the shine comes from the refined stone itself and cannot peel. Grind-and-seal stops after a coarse 80- or 120-grit diamond cut and rolls on two coats of topical polyurethane or acrylic sealer, which costs less upfront but needs recoating every 3–5 years.

Yes, provided the slab is structurally sound and at least 75–100 mm thick. Tile adhesive beds are stripped back with PCD (polycrystalline diamond) scraper segments, pinholes and spalls are grouted after the 80-grit cut, and the slab is densified and polished—though old slabs usually show more aggregate variation and character patch repairs than a purpose-poured floor.

Despite its reflective visual gloss, a mechanically honed or polished concrete floor refined to 400 or 800 grit typically achieves a wet Pendulum Test Value (PTV) above 36, giving better wet grip than many glazed porcelain tiles because the microscopic pore structure remains open.