Concrete floors—beautiful, durable, and cool enough to make your mates jealous. But here’s the question we get all the time at NZ Grinders: “Should I go for a topical coat mechanical grind, or diamond polished concrete?”
It’s a great question. And honestly, if we had a dollar for every time someone asked it, we’d be polishing the floor of our own private jet hangar.
But until then, let’s break it down in a way that doesn’t sound like a cement science lecture. We’ll tell you what each finish involves, where they work best, what they cost, and how to decide which one is right for your space.
What Is a Grind and Topical Sealed Floor?
Grind and seal is the low-maintenance cousin of polished concrete. Here’s how it works:
We grind back the top layer of concrete to expose the aggregate (the pretty stones inside). Then we apply a topical sealer—either matte, satin, or glossy—to lock in the look and protect the surface. Boom. Done.
It’s quick, cost-effective, and gives you that “polished look” without the full process.
You can choose how much – or little – stone you want.
It’s similar to putting a clear nailpolish on your fingernails.
Pros of Grind and Seal:
- Faster and more affordable
- Wide range of finish options (including high-gloss)
- Great for garages, basements, and industrial areas
- Helps seal and protect old concrete surfaces
Cons of Grind and Seal:
- The sealer will wear over time (you’ll need to recoat every few years)
- Not as hardwearing as polished concrete
- Can scratch more easily – especially if you are moving furniture around or you have pets.
What Is Mechanical Diamond Polished Concrete?
Polished concrete is the high-end, all-natural version of concrete finishing. We don’t use sealers—just good old-fashioned mechanical grinding and polishing with finer and finer diamond pads. We polish the stone. We don’t rely on lacquer to create the shine – the shine comes from the stone itself.
We apply a densifier during the process to harden the surface, then polish it to your preferred level of shine (from matte to mirror).
The end result? A floor that’s strong, stunning, and virtually bulletproof (okay, maybe not literally—but close).
Pros of Polished Concrete:
- Long-lasting with minimal maintenance
- No coatings to peel, scratch, or yellow over time
- Naturally glossy and elegant
- Great for high-traffic areas (think retail, showrooms, offices)
Cons of Polished Concrete:
- Higher upfront cost
- Requires more time and equipment
- Not ideal for outdoor or wet areas
Side-by-Side Comparison
| Feature | Grind and Seal | Polished Concrete |
|---|---|---|
| Cost | $$ | $$$ |
| Maintenance | Recoat every 2–5 years | Occasional clean |
| Durability | Medium | High |
| Finish Options | Matte, satin, gloss | Matte to high-gloss |
| Slip Resistance | Can add grit | Naturally slip-resistant |
| Best For | Garages, basements, workshops | Retail, showrooms, homes, offices |
So, Which One Should You Choose?
If you’re doing up your garage or warehouse and need a tough surface that doesn’t need to look like the Louvre, go with grind and seal. It’s reliable, budget-friendly, and gives you a great finish without the extra cost.
But if you’re building a home, showroom, or commercial space that needs to look the part and last for decades, polished concrete is the gold standard. It’s low-maintenance, sleek, and seriously impressive.
At NZ Grinders, we always ask what the floor will be used for, how much traffic it’ll get, and how shiny you want it. Then we tailor the solution to fit your space (and your wallet).
Don’t Forget the Environment
Polished concrete is also the greener option. Since there’s no topical sealer and the process uses your existing slab, you’re not adding extra chemicals or materials to the mix. It’s sustainable, easy to clean, and hypoallergenic—ideal for homes and businesses looking to tread a bit lighter.
Grind and seal can be done with low-VOC sealers too, so if you’ve got concerns about indoor air quality, talk to us about the best eco-friendly options.
How We Do It at NZ Grinders
Whether it’s a grind and seal or a full mechanical polish, we treat your floor like it’s our own. (Except we vacuum way more at your place.)
We’ll talk you through every step, show you samples, and give honest advice. No pushy sales pitches—just practical solutions, expert grinding, and a bit of classic Kiwi banter along the way.
With NZ Grinders, you’re not just getting a floor. You’re getting experience, reliability, and a finish that’ll make people stop and stare.
Final Verdict
There’s no one-size-fits-all answer here. Both grind and topical seal and mechanical diamond polished concrete have their place—and both look amazing when done right. The key is matching the finish to the function.
Need help choosing? Just give NZ Grinders a call. We love talking about floors more than most people love talking about their pets. And we’ll make sure your slab ends up looking sharp, no matter what you choose.
For more details, contact Glen at 021-434-199, serving the North Island: or for South Island inquiries, reach out to Mike at 027-281-8815. You can also contact us by email us for a prompt response from our Sales Manager Ian.