Quick answer: Sand each coat of microcement once it's dry, usually 2–4 hours after you apply it. Use a corded orbital sander with dust extraction and mesh discs. On coat 1, use 80–120 grit just to knock off high spots. On your final coat, work through 120, 180 and 240 grit for a smooth finish. Wear a P3 mask.
Sanding is the step that turns a trowelled surface into that smooth, stone-like microcement finish. It's also the step our customers ask about most on our YouTube tutorials: is it dusty?, can I hand sand a small worktop?, what grit do I use? This guide answers all of them, using the same method as our application instructions.
Quick facts: sanding microcement
| Item | What you need to know |
|---|---|
| When to sand | 2–4 hours after each coat (longer below 12–15°C) |
| Tool | Corded orbital sander with dust extraction |
| Discs | Mesh-style 125mm discs (Smirdex, Abranet or similar) |
| Coat 1 grit | 80–120 |
| Final coat grit | 120 → 180 → 240 |
| PPE | P3 mask, eye protection, gloves, Type 5/6 coveralls |
| Difficulty | Easy, once you know what you're aiming for |
When is microcement ready to sand?
Each coat is applied at grain thickness (around 0.5mm) and is normally ready to sand 2–4 hours later. Room temperature makes a big difference. Below about 12–15°C it dries more slowly, so give it longer.
Always test a small patch first. If the microcement "shreds" or balls up under the disc, it isn't ready. Leave it another hour and try again.
What grit should I use to sand microcement?
- Coat 1: 120 grit is usually enough. Drop to 80 if the surface is rougher. You're only taking off high spots and trowel ridges, not polishing.
- Coat 2 (final coat on a 2-coat system): work through 120, then 180, then 240 for a smooth, even finish.
- Coat 3 (3-coat system): sand progressively to the finish you want.
Our Sanding Disc Pack includes P60, P80, P120, P180 and P240 Smirdex ceramic mesh discs, so you have every grit covered.
Do I need an orbital sander, or can I sand by hand?
Use an orbital sander. Our application guide specifies a corded orbital sander (for example a Mirka Deros or Rutlands, not cordless) connected to dust extraction. We get asked whether hand sanding is fine for a small job, such as a 4m² worktop. Our advice is still to use a sander. It keeps the surface flat, takes a fraction of the time, and the extraction deals with the dust.
Is sanding microcement dusty?
Applying microcement isn't dusty. Sanding is where the dust comes from. That's why we use mesh-style discs: with extraction running, the dust is pulled straight through the mesh into the vacuum instead of hanging in the air. Wear a P3 mask anyway, and protect anything nearby you don't want dusted. The HSE's guidance on construction dust is worth a read if you're sanding a whole room.
How do I sand microcement, step by step?
- Check it's dry. Wait 2–4 hours, then test a small patch. If it shreds, wait another hour.
- Fit the right disc. 120 grit for coat 1 (80 if it's rough).
- Start on a low speed. Work around the surface with the extraction on, then turn the speed up a little once you're comfortable.
- Keep the sander flat. Don't tip it onto its edge, or you'll dig in and leave dips.
- Check by hand, not by eye. Microcement shows lots of texture variation that looks like unevenness but isn't. Run your palm over it to feel for high spots.
- Clear the dust. Vacuum off the surface before the next step.
- Re-prime and apply the next coat. Then repeat, finishing the final coat with 120, 180 and 240.
Video not playing? Watch How To Sand The First Coat Of Microcement on YouTube.
What are the most common sanding mistakes?
- Sanding too soon. The surface shreds and you lose material. Test first.
- Chasing perfection on coat 1. It only needs to be level, not glass-smooth. The next coat does the rest.
- Digging in with the edge of the pad. Keep it flat and keep it moving.
- Judging by eye. Use your hand.
- Skipping extraction. More dust, more mess and a harder clean before the next coat.
What happens after the final sand?
Make sure the surface is clean, dust-free and fully dry, then seal it. Microcement is inherently waterproof. The sealer adds stain resistance and durability, and it takes 7 days to reach full cure. Our guide to how many coats of sealer to apply and how long to leave between them covers the next step in detail.
Planning a project from scratch? Start with how to plan your microcement project. If you've sanded through somewhere or picked up a chip, our repair guide shows how to fix it.
What you'll need
 |
Sanding Disc Pack (1sqm) · £16.50 inc VAT Best for: having every grit from P60 to P240 in one pack View product → |
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Smirdex Ceramic Sanding Discs 125mm · from £0.82 each inc VAT Best for: topping up the grit you use most View product → |
 |
Microcement Application Tools Bundle · £33.59 inc VAT Best for: the spatula, mixing paddle and sealing kit in one order View product → |
 |
Microcement WORKTOP Kit · from £205.50 inc VAT Best for: a complete worktop project in a 5m² or 10m² kit View product → |
Frequently asked questions
Can I use a cordless sander on microcement?
Our application guide specifies a corded orbital sander (for example a Mirka Deros or Rutlands) rather than a cordless one, connected to dust extraction. You need steady power and suction for the whole surface.
Can I hand sand a small microcement worktop?
We recommend an orbital sander with dust extraction even on a small worktop. Sanding by hand makes it harder to keep the surface level and puts more dust in the air.
Is it normal to see the mesh tape after sanding the first coat?
Yes. The mesh tape over board joints often shows through coat 1. That's normal: sand off the high spots, re-prime and the next coat covers it.
Do I need to re-prime after sanding?
Yes. Clear the dust, then sand and re-prime between coats as set out on our Microcement Worktop Kit page and shown in our tutorial videos. Primer comes as standard in the Microcement Worktop Kit.
What dust mask should I wear when sanding microcement?
Wear a P3 dust mask, eye protection and gloves. Our guide also recommends Type 5/6 disposable coveralls and suitable footwear.
When can I seal after the final sand?
Once the surface is clean, dust-free and fully dry. Then follow the instructions that come with the Concrete Lab Sealer. The sealer takes 7 days to reach full cure.
Still not sure? We're happy to talk you through it — info@concretelab.co.uk
