Concrete floors have made an unlikely journey from industrial utility surface to one of the most sought-after domestic finishes in the UK. Polished concrete in kitchen extensions, microcement in bathrooms, sealed screed in open-plan living rooms — the material is everywhere. And yet how to clean concrete floors properly remains genuinely misunderstood, partly because the cleaning approach depends entirely on the type of concrete surface you have, and partly because some of the most instinctive cleaning choices — bleach, vinegar, all-purpose spray — cause real damage to sealed and polished finishes.
This guide on how to clean concrete floors and what to use covers every concrete floor type found in UK homes and commercial spaces, with the cleaning methods and products appropriate to each. Unsealed concrete in garages and basements. Sealed concrete in living spaces and extensions. Polished and densified concrete in contemporary interiors. Decoratively stained and coloured concrete. Outdoor concrete paths and patios. Each one has different requirements — and understanding which surface you have is where the guide starts.
Step One: Know What Type of Concrete Floor You Have
Before reaching for any cleaning product, identify the type of surface. The same liquid that cleans one type of concrete floor effectively will permanently damage another.
Unsealed Concrete
Uncoated, untreated concrete with no surface finish applied. Common in garages, utility rooms, workshops, cellars, and older basement floors. The surface is porous — it absorbs liquids readily and stains easily. It has a typically grey, slightly rough texture. You can test for sealing by dropping a few drops of water on the surface: if the water absorbs within a few minutes, the floor is unsealed. If it beads, a sealer is present.
Unsealed concrete can tolerate stronger cleaning products than sealed surfaces because there’s no surface treatment to protect. It can be scrubbed hard, treated with degreasers, and cleaned with stronger alkaline products than you’d use on a polished floor.
Sealed Concrete
Concrete with a surface sealer applied — either a penetrating sealer (which sits within the pores of the concrete without forming a visible surface film) or a topical sealer (which forms a protective coating on the surface). The most common type of sealed concrete floor in UK domestic settings. Sealed floors resist staining and moisture better than unsealed ones but require gentler cleaning to protect the sealer itself.
You can usually identify a topical sealer by a slight sheen to the surface and a feel of having a coating on top of the concrete. Penetrating sealers produce little visual change but the water bead test confirms their presence.
Polished Concrete
Concrete that has been mechanically ground and polished through multiple progressive diamond-tooling stages to produce a smooth, glossy or satin finish. Often treated with a chemical densifier during polishing to harden the surface and then finished with an impregnating sealer or topical polish. The most visually refined domestic concrete finish — used in high-specification kitchens, living rooms, and commercial interiors.
Polished concrete requires the most careful cleaning approach of all concrete types. The surface can be scratched by abrasive materials, stripped by acid cleaners, and dulled by cleaning product residue if rinsed inadequately. It looks and feels significantly different from basic sealed concrete — noticeably smoother and more reflective.
Decorative Stained or Coloured Concrete
Concrete treated with reactive acid stains, water-based stains, or integral colour added to the mix at pour stage, then typically sealed to protect the decorative finish. Common in commercial spaces and increasingly in domestic extensions. The colour is intrinsic to or deeply embedded in the surface, but the sealer protecting it responds to cleaning products in the same way as any other sealed concrete.
Outdoor Concrete
Paths, patios, driveways, and external slabs. Typically unsealed or treated with a penetrating sealer for frost resistance. Exposed to weather, algae, moss, oil from vehicles, and the general grime of outdoor use. Outdoor concrete cleaning involves more robust methods than indoor concrete — pressure washing and stronger cleaning products are appropriate here in a way they’re not for polished interior floors.
The Universal Rules: What Never to Use on Concrete Floors
Before the type-specific guidance, these rules apply across every concrete surface indoors and should be memorised:
Never use vinegar or other acid-based cleaners on sealed, polished, or stained concrete. This is the most common cleaning mistake and one of the most damaging. Vinegar, citric acid, and other acidic cleaning products etch concrete and dissolve sealers. Even diluted, regular use will progressively strip the surface protection, dull polished finishes, and eventually expose the underlying concrete to staining and moisture. The fact that vinegar is a popular natural cleaner for other surfaces does not make it safe for concrete.
Never use bleach on sealed or polished concrete. Bleach strips sealers and discolours decorative finishes. It’s appropriate only for outdoor unsealed concrete where algae or organic matter needs killing — and even there it should be used sparingly and rinsed thoroughly.
Never use ammonia-based cleaners. These include many glass cleaners and some general-purpose sprays. Ammonia degrades the binders in concrete sealers over time.
Never use abrasive scrubbing pads on polished concrete. Steel wool, scouring pads, or any abrasive material will scratch polished surfaces that have taken multiple grinding and polishing passes to achieve. Use microfibre cloths or soft floor pads.
Never leave water pooled on sealed or polished concrete. Excess water sitting on the surface can penetrate any micro-defects in the sealer and leave marks as it evaporates. Damp mop — don’t flood.
How To Clean Concrete Floors That Are Unsealed Concrete
Unsealed concrete in garages, workshops, and utility areas tolerates robust cleaning. The goal is to lift oil, grease, tyre marks, and general grime from a porous surface that has absorbed them to varying depths.
Daily and Weekly Maintenance
Sweep or blow out dust and loose debris regularly. Fine grit and dust act as abrasives underfoot and accelerate surface wear — removing them frequently is more effective than periodic deep cleaning. A stiff-bristle broom or a leaf blower for larger areas.
General Cleaning
Warm water with a small amount of washing-up liquid or a diluted alkaline floor cleaner applied with a stiff scrubbing brush or a floor scrubber. Work in sections, scrub the surface, and rinse thoroughly with clean water. Allow to dry fully before use — unsealed concrete dries more slowly than other floor types.
For outdoor unsealed concrete, a pressure washer is highly effective and saves considerable labour. Use a wide-angle nozzle rather than a concentrated jet, which can erode the concrete surface. Keep the nozzle moving rather than holding it static.
Oil and Grease Stains
The most common and most stubborn problem on garage and workshop floors. Act quickly — oil penetrates unsealed concrete rapidly and becomes progressively harder to remove the longer it’s left.
Fresh oil spills: Absorb as much as possible immediately with cat litter, sawdust, or a proprietary oil absorbent granule. Leave for 30–60 minutes, sweep up the absorbent, then treat the residual stain. Do not rub — blot or sweep.
Established oil stains: Apply a concrete degreaser (sodium lauryl sulphate or alkaline-based degreasers from trade suppliers — Pro-Kleen, Fila, or equivalent) directly to the stain. Allow to dwell for the time specified on the product (typically 10–20 minutes). Scrub with a stiff nylon brush. Rinse with hot water. Repeat if necessary — deep-set oil stains may require multiple applications.
For very stubborn stains: A poultice method — mixing the degreaser with an absorbent powder (talcum powder or fuller’s earth) to form a paste, applying it to the stain, covering with cling film, and leaving overnight — can pull oil out of deep pores more effectively than surface application alone. Remove the dried poultice the following day and rinse.
Rust Stains
Rust on concrete floors comes from steel objects left in contact with the wet surface, from corrosion of embedded reinforcement, or from iron minerals in the aggregate. An oxalic acid solution — available from hardware and builders’ merchants — applied to the rust stain, left to work for 15–30 minutes, then scrubbed and rinsed, removes most rust staining effectively. Apply carefully to the stain only and rinse thoroughly afterwards.
Note: oxalic acid is not suitable for polished, sealed, or decoratively stained concrete — the acid etching risk applies here. Reserve it for unsealed surfaces only.
Paint and Adhesive
Paint spills on unsealed concrete respond to paint stripper or a proprietary concrete paint remover, applied and left to soften the paint before scraping and rinsing. For large areas of old paint, mechanical removal — grinding or shot blasting — is more practical than chemical stripping. Adhesive residues can often be softened with a commercial adhesive remover, then scraped up.
Cleaning Sealed Concrete
The approach for sealed concrete is gentler than for unsealed, because the goal is to clean the surface without degrading the sealer that’s protecting it.
Routine Maintenance
Dust mop daily or as required in high-traffic areas. Fine grit on sealed concrete acts as sandpaper underfoot and will progressively scratch the surface — removing it frequently is the single most protective thing you can do.
Damp mop weekly or when needed with warm water and a pH-neutral floor cleaner. The pH-neutral requirement is non-negotiable — anything acidic or strongly alkaline will degrade the sealer over time. Products specifically formulated for sealed concrete floors include Fila PS87 Cleaner, Lithofin Cement-Off (despite its name, appropriate for maintenance not heavy cleaning), and various branded concrete cleaners from Mapei, Sika, and similar.
Dilute according to the manufacturer’s instructions — using stronger concentrations doesn’t improve cleaning performance and leaves residue. Mop in sections, rinse with a separate clean-water mop pass, and allow to dry.
Avoid allowing mop water to pool or sit — wring the mop thoroughly before application and work in sections small enough to dry within a few minutes.
Spills
Act fast. The sealant stops instant staining, but you need to clean spills promptly. The longer an acidic liquid sits, the more it eats into the sealer. Blot — don’t rub — with a paper towel or absorbent cloth to lift the spill rather than spreading it. Clean the area with a damp cloth and pH-neutral cleaner, rinse, and dry.
Red wine, coffee, and fruit juice are all acidic — they’re your main adversaries on a sealed floor. Clean them up immediately and they cause no damage. Left for hours, they begin to etch into and through the sealer.
Stubborn Marks and Scuffs
Black rubber marks from shoes or furniture legs respond to a small amount of isopropyl alcohol (IPA) on a soft cloth, rubbed gently. IPA is solvent enough to lift the mark without degrading most sealers — test in an inconspicuous area first.
Avoid abrasive scrubbing on sealed floors. A soft white cleaning pad (the type used for floor scrubber machines) is the most aggressive surface appropriate for regular cleaning.
Restoring Dull Areas
Sealed concrete floors that have seen heavy use develop dull patches where the sealer has worn down. In mild cases, a maintenance coat of sealer applied to the affected area restores the appearance. In more significant cases, resealing the whole floor is required. This is not a frequent requirement — a well-maintained sealed floor typically needs resealing every three to five years in a domestic setting.
Cleaning Polished Concrete
Polished concrete demands the most fastidious approach of any floor type. The glossy surface that makes it so visually impressive is also the surface that shows every piece of grit, every smear, and every cleaning product residue with uncommon clarity.
Routine Maintenance
Dust mop daily with a microfibre dust mop. On polished concrete, this isn’t optional maintenance — it’s the primary protection against surface scratching. Grit and sand particles ground underfoot by every footfall scratch polished concrete progressively, dulling the finish over time. Removing them before they can do this damage is the single most important maintenance action.
Avoid bristle brooms with stiff bristles — they can scratch polished surfaces. Soft microfibre or treated cotton dust mops are appropriate.
Regular Cleaning
Damp mop with a pH-neutral cleaner specifically formulated for polished concrete. The product must be genuinely pH-neutral — not approximately neutral, not a product that claims to be gentle but has acidic or alkaline components. Products commonly used by polished concrete specialists in the UK include Klindex Floor Active, Fila Floor Expert, and HTC Clean products. Many polished concrete installers specify their own preferred maintenance product when they hand over a floor — follow their recommendation if you have one.
Apply with a flat-head microfibre mop, damp not wet. Work in sections and rinse with a clean-water pass before the cleaning solution dries on the surface. Dried cleaning product residue on polished concrete produces a dull, smeared appearance and requires additional work to remove.
Dry with a clean microfibre cloth or allow to air dry in a well-ventilated space. Do not walk on a wet polished floor — wet footprints leave marks that dry onto the surface.
Spills on Polished Concrete
Blot immediately — never rub. Use a paper towel or absorbent cloth, working inward from the edges of the spill to avoid spreading. For acidic spills (wine, juice, vinegar accidentally used), clean the area promptly with pH-neutral cleaner and a damp cloth. Rinse and dry. If the spill has been left to sit and has etched the sealer, localised resealing by a polished concrete specialist is the repair.
Deep Cleaning and Shine Restoration
For polished concrete floors sealed with an impregnating sealer, the use of a diamond non-woven pad — such as the HTC Twister system — is the professional standard for periodic deeper cleaning and shine restoration. These pads use embedded diamond microcrystals to gently clean the surface while maintaining or enhancing gloss levels. They’re attached to a standard floor polishing machine (available for hire) and used with water only — no additional cleaning products.
For most domestic settings, a full clean using a Twister-type pad once or twice a year, alongside the daily and weekly microfibre maintenance, keeps polished concrete in excellent condition indefinitely.
The talcum powder poultice method mentioned for unsealed concrete also works for localised stains on polished surfaces: mix talcum powder with a small amount of pH-neutral cleaner to form a paste, apply to the stain, cover with cling film, pierce the film once or twice, and leave overnight. The drying paste draws the stain out of the pores. Remove the dried poultice the following day and clean as normal.
Cleaning Decorative Stained and Coloured Concrete
Treat decorative concrete as you would sealed concrete — the sealer protecting the decorative finish responds to cleaning products in the same way. pH-neutral cleaner, soft mop, prompt spill treatment, no acids or bleach. The colour is durable but the sealer protecting it is not indestructible.
The one additional consideration for stained or coloured concrete is UV exposure in rooms with significant direct sunlight. Some concrete stains fade under prolonged UV exposure, and maintaining an adequate sealer coat — which provides some UV protection — is more important on these floors than on plain concrete.
Cleaning Outdoor Concrete
Outdoor concrete patios, paths, and driveways are exposed to a range of problems that indoor concrete isn’t: moss, algae, lichen, oil from vehicles, fertiliser staining, tyre marks, and general outdoor grime. The approach is significantly more robust than for indoor surfaces.
Moss, Algae, and Lichen
The most common outdoor concrete problem in the UK. In shaded or north-facing areas, biological growth can establish quickly and becomes genuinely slippery when wet. Two approaches:
Pressure washing: Highly effective for established moss and algae. Use a 40–60° fan nozzle, not a concentrated jet. Keep the nozzle moving. A surface cleaner attachment — a spinning nozzle head enclosed in a housing — is more efficient on large areas and prevents the uneven striping that a single nozzle produces. Pressure wash the whole surface consistently, working from the highest point downward so rinsed water doesn’t flow back over cleaned areas.
Biocidal treatment: Proprietary path and patio cleaners containing benzalkonium chloride or similar biocide kill moss and algae and continue to inhibit regrowth for months after application. Products include Pro-Kleen Path & Patio Cleaner, Wet & Forget, and Patio Magic. Apply to the affected area, allow to work (some require 24–48 hours for full effect), then pressure wash or brush clean. These products are particularly effective as a maintenance treatment after physical cleaning, preventing rapid regrowth.
Oil Stains on Outdoor Concrete
Treat as for garage floors — absorbent granules for fresh spills, proprietary concrete degreaser for established stains. Pressure wash after treatment. For very old, deeply penetrated oil stains on driveways, specialist driveway cleaning contractors using heated water pressure washers achieve significantly better results than cold-water domestic pressure washers.
General Outdoor Cleaning
A stiff-bristle yard brush with a diluted alkaline cleaner (washing soda solution works well and is inexpensive) scrubbed into the surface and rinsed with a pressure washer or hose handles most outdoor concrete maintenance. For a thorough annual clean, the pressure washer alone — without additional chemicals — removes a season’s accumulated grime effectively.
Products Summary: What to Use on Each Surface
| Floor Type | Routine Cleaning | Stain Treatment | What to Avoid |
|---|---|---|---|
| Unsealed | Alkaline floor cleaner, scrub brush | Degreaser for oil; oxalic acid for rust | Nothing to strip — relative freedom |
| Sealed | pH-neutral concrete cleaner, damp mop | IPA for rubber marks; pH-neutral for spills | Acids, bleach, ammonia, abrasives |
| Polished | pH-neutral polished concrete cleaner, microfibre | Talcum powder poultice; diamond pads | Acids, abrasives, anything not pH-neutral |
| Stained/Coloured | As sealed | As sealed | As sealed; especially protect sealer from UV |
| Outdoor | Alkaline cleaner + pressure wash; biocide | Degreaser for oil; pressure wash | Avoid concentrated acid jets that erode surface |
When to Reseal
Cleaning maintains the floor — resealing extends its life and restores appearance when the protective layer has worn down.
Signs that resealing is needed: water no longer beads on the surface; the floor looks dull even after cleaning; stains are penetrating more readily than before; the texture feels rougher than when the floor was new.
Resealing requires thorough cleaning first — any contamination under the new sealer will be permanently preserved. For polished concrete, resealing is a specialist job best returned to the original installer or a polished concrete maintenance contractor. For simpler sealed surfaces in utility spaces, a DIY resealing with an appropriate penetrating or topical sealer is achievable with reasonable care.
The better the regular maintenance, the less frequently resealing is needed. A well-maintained polished concrete floor properly cleaned can retain its appearance for five to ten years before the sealer requires renewal. A neglected floor, cleaned with the wrong products and grit allowed to scratch the surface, may need attention within two or three years.
Regular maintenance is cheaper than restoration. That’s as true for concrete floors as it is for anything else.
