5 Mistakes People Make Choosing Polished Concrete

Polishing an existing slab? You can't choose the colour, the cement and aggregate are whatever is under the surface. Sometimes grey cement, sometimes brown; usually bluestone, sometimes a gorgeous river pebble. You won't know until grinding starts, and it is almost always lovely, but ask your contractor for a sample patch if you're concerned.

Lifting old tiles to polish underneath? Bleach and cleaning products can leach through old grout over the years and stain the concrete below. It may only show late in the process, so it is important to know it can happen.

Some companies only mechanically polish, others only grind & seal (a coating that mimics polished concrete), and many won't explain the difference. Choose carefully, and look for:

• Qualified, experienced and QBCC-licensed. No two slabs are the same, so you want someone who can advise you properly for your project.
• A specialist, not a dabbler. Pick a contractor who specialises in polished concrete, not an epoxy company that does it occasionally.
• Genuine reviews, built over years. Poor operators delete bad reviews or post fake ones. Be wary of a company racking up loads of reviews every month, a genuine business typically gains only 2–5.
• A real website with contact details. Phone, email and a physical address, so you can reach them if anything goes wrong down the track.
• A contractor who offers various finishes. Mechanical polishing isn't always suitable once you start, your slab may grind up softer or harder than expected, so you want someone who can switch to a feather finish or coating if needed.
• A showroom you can visit. A physical place to find them, and a sign they're committed to helping you choose the right finish before they start.

There are two types of polished concrete, each with three exposure levels and three gloss levels, 18 combinations before you even choose a coating (water-based, solvent-based, polyaspartic, UV-stable and more).

Some finishes aren't suited to outdoors or wet areas, and some yellow over time if untreated. A few need re-coating every 5–7 years, which can mean moving furniture out for the week. Get pricing on all your options up front, some changes mid-job are easy (matte to semi-gloss MPC); others mean starting again and paying twice.

Choose a contractor who shows you samples you can see and touch, and who recommends the finishes that genuinely suit your slab.

Every floor comes with cleaning and maintenance instructions that should be followed once it's finished, but some contractors never explain them, or you forget them months later when you need them.

For example, you can't use vinegar on a mechanically polished floor, and you shouldn't let water pool on the surface. After a grind & seal you may need to wait up to seven days before moving furniture back; on a mechanically polished floor you can do it almost immediately. Some finishes need re-coating every few years, leave it too long and you may have to grind back and start again.

Insist on written care instructions the day your floor is finished, so there are no nasty surprises, and no paying another contractor to redo the job later. (Ask your contractor to leave you a container of the dust from grinding your floor too, it colour-matches perfectly if minor hairline cracks ever need repair.)

You get what you pay for, and that's certainly true of polished concrete. Cheap can mean a second-hand grinder being tested on your floor, a one-person operator who disappears mid-job, or budget products that won't deliver the look. Even a respected contractor can't get the best result if the budget won't allow the right products.

You can't put a price on a floor that turns heads, and unlike a rug or couch, you won't be replacing it. We are often called in to rectify cheap jobs that went wrong. The key thing is to do your research, choose someone proven, and not cut the corners you can't undo.