Technical detail · polished concrete floors
The chemistry of sealing polished concrete.
The specifier-level version. Polished concrete is one of the strongest substrates our chemistry has to work with: grinding exposes both the cement paste and the quartz aggregate, and both carry the surface hydroxyls a mineral sol-gel grafts to. This page carries what is specific to a polished floor: the dual bond, the partnership with a densifier, and the honest limits on cement. For the shared science, it points you deeper into the pillars.
At a glance
MineralProtect on this floor.
C-S-H paste plus quartz aggregate: a genuine covalent-bond case, like concrete generally.
Inorganic Si to O to Si network. Colourless, non-pigmenting, low-VOC.
A nano-thin conformal layer, not a pore-deep impregnation and not an on-top film.
Leaves the pore network open, so the slab still releases moisture. Framed against films.
Alters surface energy only. Same colour, finish and level of gloss.
On the repellency function, per job, on top of Australian Consumer Law rights.
The bond
Why the bond is real here.
A mineral sol-gel cures at the surface into a dense Si to O to Si network, roughly 90 to 100 nanometres thin, colourless and breathable. The shared mechanism, and why bonding at the surface beats a film or a pore sealer, is set out in full in how sealing works and stone and sealer chemistry. What matters here is the surface a polished floor gives it to grab.
Grinding exposes two reactive surfaces at once
Polishing a floor cuts back to both the calcium-silicate-hydrate cement paste and the quartz aggregate, and lays them side by side at the face. Both carry reactive silanol groups that condense with the sol's silanols into genuine covalent Si to O to Si bonds continuous with the surface. On cure the coating is chemically integrated with the floor, not adhered to it. This is the strong-bond case, the same one concrete gives broadly.
Density, not hardness, carries the durability
The load-bearing property is the density and cross-link redundancy of the network, not a mechanical hardness figure. On a trafficked floor it fades by slow nano-scale abrasion rather than a cliff-edge failure, and it renews with a top-up on a clean surface, because a bonded surface network can be rebuilt where a pore-deep reservoir cannot wick up to renew an abraded face.
The one comparison specific to this floor
Why a densified floor still stains.
Most polished concrete has already been treated, with a silicate densifier. A densifier and a sol-gel are not rivals, they are partners doing two different jobs. This is the comparison that only matters on a polished floor. For the full head-to-head against films and pore sealers, see the three ways to seal a surface compared.
The densifier's job
Hardens the slab, leaves it open
A silicate densifier reacts with free lime in the paste to harden and dust-proof the slab. It does that mechanical job well. But it leaves the surface energetically open: it does not repel water or oil, because repelling was never what it was for. A densified floor is a harder floor, not a protected one.
The sol-gel's job
Does the half a densifier can't
The sol-gel lowers the surface energy, so water, oil and staining liquids sit on top and lift in cleaning instead of soaking in. Most polished floors have the hardening and are missing the repelling, which is exactly why a floor can look sealed and still ring-mark from a wine glass or a coffee cup. We do not replace the densifier. We finish the job it started, at the surface where the staining happens.
On a polished floor
The four loads, read on a floor.
Every load a floor takes, the mop and scrub pad, the detergent, the sun through the glazing and the dropped oil, acts in the top sub-millimetre, which is where the network sits. The four resistances, cleaning, chemical, UV and oil, and the honest bound on each, are set out in full in the four real-world resistances. Here is how they read on a polished floor specifically.
Cleaning and abrasion
The mop, scrub pad, grit and foot-traffic lanes. Durability is network density, not hardness, so it fades slowly and tops up without a strip. Not scratch-proof, and abrasion is not guaranteed.
Oil
The kitchen and living-floor case: olive oil, cooking splatter, red wine and coffee sit on the surface and lift in cleaning rather than soaking in. Oil is an outcome here, never a number, and a spill left for days can still mark.
Chemical
Built for the routine alkaline detergents of floor maintenance, the same exposure that fails a pore sealer from inside. More resistant, not immune. Keep strong acids off, they attack the cement itself.
UV
The sun stripe a glazed room throws across a floor. The inorganic backbone does not yellow or chalk the way an organic acrylic or urethane guard does. Far more UV-stable, not UV-proof and not permanent.
The family evidence we publish is GlassProtect, still beading above 100 degrees after 3,000 cream-cleanser cycles, around 3 times slower repellency loss than the leading brand. On concrete we judge it on how the surface sheds water and oil over time, not a cycle number we cannot stand behind on your floor.
The honest limits
Where it stops.
- Not permanent, not maintenance-free, not stain-proof. A long-lasting treatment that degrades slowly and predictably and needs periodic top-up. Silicate chemistry is more resistant, not immune.
- No penetrating sealer stops acid etching. Etching is the acid dissolving the cement itself, not a stain on top, so sealing slows absorption and buys wipe-up time. It does not make cement acid-proof. Etch prevention is a glass-only claim, not a concrete one.
- Beading fades before the barrier does. Loss of visible beading is a prompt to re-test, not proof of failure. The decoupling is partial, not total, so we never claim the coating is fully intact once the bead has gone.
- Prep decides longevity. A weak or contaminated surface fails every sealer class the same way. The floor is assessed and prepared to a certified standard before any coating goes on. The chemistry is only half of it.
Specifier questions
The technical detail.
Does the coating consolidate or strengthen the concrete?
No, and we don't claim it does. Deep sol-gel consolidants are a separate class that penetrate millimetres and re-cement loose grains. MineralProtect is a thin surface coating, around 90 to 100 nanometres, that engineers the surface energy. Hardening the slab is the densifier's job, not the sealer's.
What is the chemical working range?
The bonded network is stable through routine alkaline detergents and mopping at cleaning-strength pH and short contact times. It is more resistant, not immune: silicate chemistry hydrolyses at high alkalinity, and strong acids attack the cement itself. For everyday floor cleaning it is well within range. Keep undiluted acids off it.
Do you have a scrub or Taber figure for MineralProtect?
We hold MineralProtect to the recognised abrasion and scrub standards, Taber, ASTM D2486 and ISO 11998, but we don't publish a cycle number for it, because we won't quote a figure we can't stand behind on your floor. The family evidence we do state is GlassProtect, still beading above 100 degrees after 3,000 cream-cleanser cycles. On concrete, judge it on how the surface sheds water and oil over time.
Is it PFAS-free, and what about VOC?
PFAS-free by design, not by reformulation: the oil behaviour comes from an inorganic mechanism that never needed fluorine. The historic oil-repelling stone sealers were fluoropolymer, and those specific PFAS are being regulated out in Australia. MineralProtect is water-based and low-VOC. Full safety data sheets are available on request.
How does it renew, and what does the guarantee cover?
It wears by slow nano-abrasion with no cliff-edge, and it tops up over itself on a clean surface with no stripping, unlike a failed film that has to be buffed back or recoated. Every job is registered under a 10-year guarantee covering the repellency function, with re-treatment of the affected area as the remedy, sitting on top of your Australian Consumer Law rights.
Go deeper
The shared science, in the pillars.
This page covered what is specific to a polished floor. The mechanism it rests on is set out in full here.
How sealing works
The third class of sealer from the ground up: what a sol-gel does, and why bonding at the surface changes the outcome.
Read the pillarThe four real-world resistances
Cleaning, chemical, UV and oil, the four loads that decide a seal, each with its honest bound, and why a pore sealer cannot meet them.
Read the pillarThe three ways to seal, compared
Film against impregnator against the bonded coating, on one axis: where it protects, whether it breathes, and how it renews.
Read the pillarGet a quote
Seal it with the next generation.
We'll assess your polished concrete, prepare it to a certified standard and seal it with MineralProtect, registered under a 10-year guarantee. Confirmed price before you book.