People search for concrete floor sanding when a slab or screed is too rough, too dusty or too lumpy for the floor that is going on top. The word "sanding" covers several different machines, and only some of them do anything useful on concrete.
Short answer: you can sand a concrete floor, but only lightly. Sanding with an abrasive disc removes surface dust, light laitance and small nibs. High spots, trowel ridges, old adhesive, paint and thick laitance need diamond grinding, and a floor that dips or slopes needs levelling compound or a new screed instead.
Below we set out what each method removes, what HSE expects about silica dust on any job that sands or grinds concrete, and what the hire and professional routes cost, using 2026 UK figures from named sources.
Can you sand a concrete floor?
Yes, within limits. Concrete and cement screed are hard, abrasive materials. A sanding disc or mesh wears quickly against them and takes off very little material per pass. That makes sanding fine for cleaning up a surface and poor at changing its shape.
It also matters which "sander" you mean:
- Drum and belt floor sanders from a hire shop's floor sanding range are built for timber floorboards. They are designed for wood, so they are the wrong machine for a concrete slab.
- Rotary or orbital machines with abrasive discs or mesh can lightly abrade a screed surface. This is how the thin laitance on a calcium sulphate (anhydrite) screed is often sanded off once the screed is dry, before priming.
- Floor grinders with diamond heads are what most people actually need. They look similar but cut the surface rather than polishing it.
Our concrete floor grinding service page explains how grinding works in detail. This post is about deciding whether light sanding is enough, whether to hire, and what each route costs.
Sanding vs diamond grinding: what each removes
| Problem on the floor | Light sanding (abrasive disc or mesh) | Diamond grinding | If neither fixes it |
|---|---|---|---|
| Surface dust and light contamination | Yes | Yes | Not needed |
| Laitance on a dry calcium sulphate screed | Usually, as part of normal preparation | Yes | Not needed |
| Thick or hard laitance on concrete | Slowly, often not fully | Yes | Shot blasting on large areas |
| Trowel marks, nibs, small lips | Small nibs only | Yes | Not needed |
| Ridges and humps of a few millimetres | No, too slow | Yes | Levelling compound after grinding |
| Old carpet, vinyl or tile adhesive | No, clogs the abrasive | Yes, most residues | Scarifying for heavy build up |
| Floor paint and thin coatings | No | Yes | Scarifying for thick coatings |
| A floor that dips or slopes across the room | No | No | Levelling compound or a new screed |
Swipe the table sideways to see every column.
Flooring manufacturers expect this level of preparation. Karndean's glue down installation guide (November 2023) tells installers to mechanically abrade all concrete floors to remove laitance, paint, plaster and adhesive, and says power floated concrete may need diamond grinding, scarification or light shot blasting so the adhesive can grip. A quick hand sand over a contaminated slab does not meet that.
What "flat enough" means
BS 8204 sets surface regularity classes for screeds measured under a 2 metre straightedge: SR1 allows 3mm, SR2 5mm and SR3 10mm. SR1 is the class many thin sheet finishes, such as LVT and sheet vinyl, ask for, so check the flooring maker's own tolerance. If a straightedge shows gaps well above that across the room, no amount of sanding or grinding will get you there on its own. Our guide to screeding before flooring lists what each floor covering asks for.
Silica dust: what HSE expects on any concrete sanding job
This is the part DIY guides tend to skip. Concrete contains a lot of silica: HSE's silicosis page puts concrete and mortar at 25% to 70% silica. Sanding or grinding it produces respirable crystalline silica (RCS). HSE's construction dust sheet warns that this dust builds up in the lungs gradually, and by the time the effects are noticed the damage may already be serious.
HSE's figures and guidance are clear:
- The workplace exposure limit for RCS in Britain is 0.1 mg/m³ as an 8 hour time weighted average.
- HSE's construction dust sheet (CIS36) says over 500 construction workers are believed to die each year from exposure to silica dust.
- Breathing it can cause silicosis, chronic obstructive pulmonary disease (COPD) and lung cancer. HSE notes silicosis keeps developing after exposure stops and cannot be reversed.
For grinding concrete with hand operated tools, HSE's COSHH essentials sheet CN1 sets out the controls:
- On-tool extraction with an extraction hood and an M or H Class extraction unit, with the right hoses and connections.
- Respiratory protective equipment with an assigned protection factor (APF) of at least 20, face fit tested if it is a tight fitting mask, worn by someone who is clean shaven.
- Cleaning up by vacuuming with an M or H class vacuum or using wet methods. CIS36 adds: do not just use a general commercial vacuum.
- Limiting who is nearby, so only the people doing the work are in the dusty area.
COSHH places these duties on employers. A homeowner sanding their own garage floor is not an employer, but the dust does the same damage to your lungs and to anyone else in the house. If you hire kit, hire the extractor with it, not a household vacuum.
Hire costs vs professional grinding costs
Hiring a sander or grinder yourself
Hire prices change by depot and week, so check them on the day rather than trusting an old list. When you ask for a price, get it for the whole kit:
- the grinder or sander itself, per day and per week;
- an M or H Class dust extractor to match it;
- diamond discs, segments or abrasive, and whether they are included or charged separately;
- delivery and collection if you cannot carry it;
- a suitable mask, if you do not already own RPE rated APF 20 or more.
trade2base's plant hire guide (June 2026) says weekly rates are usually about three to four times the daily rate, and that if you will have the kit for four days or more, the weekly rate is almost always cheaper. It also puts delivery or collection of larger plant at £40 to £100 or more per leg.
Then add your own time. A first timer with a hand held grinder works far slower than a walk behind machine, and edges and corners still need a smaller tool.
Paying a contractor to grind
Published 2026 UK figures from trade2base, a pricing resource for tradespeople:
| Work | Typical UK rate, 2026 | Source |
|---|---|---|
| Diamond grinding before a floor coating, domestic or small commercial | £3 to £8 per m² | trade2base, epoxy floor costs, June 2026 |
| Floor grinding or scarifying before new flooring | £5 to £15 per m² | trade2base, flooring installation costs, June 2026 |
| Grinding or shot blasting before resin, depending on slab condition | £8 to £20 per m² | trade2base, epoxy resin floor costs, June 2026 |
| Self levelling compound over concrete | £10 to £20 per m² | trade2base, flooring installation costs, June 2026 |
| Flooring contractor day rate | £200 to £350 per day | trade2base, epoxy floor costs, June 2026 |
Swipe the table sideways to see every column.
As a rough worked example using those figures: grinding a 20 m² kitchen floor at £5 to £15 per m² comes to £100 to £300 before VAT and extras. On a small room a contractor may price by the day instead, which is where the £200 to £350 day rate applies. Old adhesive, several coats of paint or very hard concrete push a job to the top of each range, because they take more passes.
The professional price normally includes the machine, tooling, extraction, protection of adjoining rooms and clearing the dust. Those are the items that make a DIY hire cost more than it first looks.
Which route makes sense?
| Situation | Sensible route |
|---|---|
| A few nibs or a dusty surface on a small, otherwise flat floor | Light sanding or a hand held grinder with extraction |
| Laitance on a dry anhydrite screed before tiling | Sanding or light grinding, then the primer the adhesive maker specifies |
| Adhesive, paint or ridges over a whole room | Professional grinding |
| A floor out of level by more than a few millimetres | Grinding plus levelling compound, or a new screed |
Swipe the table sideways to see every column.
When neither is enough and the floor needs levelling
Sanding and grinding change the surface. They do not raise low areas. If a 2 metre straightedge rocks on a hump or shows a dip, the usual answer is to grind off the high spots and contamination, then lay a thin levelling compound, usually about 2mm to 10mm, to bring the floor to SR1.
Grinding a whole floor down to its lowest point is slow and expensive, and on a screed it can leave the layer thinner than its minimum depth, especially over insulation or underfloor heating. Where the floor is badly out, a new screed is often cheaper than chasing it with a grinder. Our comparison of latex, self levelling compound and screed explains where each one stops working.
Most real floors need a mix: grind, repair cracks and hollow patches, prime, then level. That sequence is what we mean by floor preparation.
Get a fixed price for your floor
If you are not sure whether your floor needs sanding, grinding, levelling or all three, send us:
- a few photos of the floor, including close ups of any adhesive, paint or ridges;
- the floor area in m²;
- what is going on top (LVT, tiles, engineered wood, carpet or something else);
- whether it is concrete, sand and cement screed or anhydrite screed, if you know;
- your postcode.
We will tell you whether it needs grinding, levelling or both, and give you a fixed price agreed before any work starts. We call back the same day and send a written quote within 24 hours. We work with dust extraction on every grinding job, and we cover the towns within about 80 miles of Slough listed on our areas page.
Request a quote online or call 07466 650936.
Sources
- HSE: Silicosis, causes and risk controls, Health and Safety Executive, accessed 1 October 2026
- HSE: Construction dust, Construction Information Sheet 36, revision 3, Health and Safety Executive, revised March 2020, accessed 1 October 2026
- HSE: COSHH essentials in construction, CN1 scabbling or grinding, Health and Safety Executive, accessed 1 October 2026
- BSI: BS 8204-1, concrete bases and cementitious levelling screeds to receive floorings, BSI, accessed 1 October 2026
- Karndean: glue down installation guidelines, UK, Karndean Designflooring, November 2023
- trade2base: epoxy floor costs UK, trade2base, 8 June 2026
- trade2base: epoxy resin floor costs UK, trade2base, 12 June 2026
- trade2base: flooring installation costs UK, trade2base, 8 June 2026
- trade2base: plant hire for trade businesses UK, trade2base, 14 June 2026
