When does polished concrete need resealing? The water test and the reseal matrix
A two-minute water test tells you whether your sealer is still working. The matrix tells you roughly when to start testing, by finish, setting and traffic.
By Jeremy Thomason. Updated .
The water test
Put a few drops of water on the floor somewhere that gets used - a doorway, in front of the sink, the main traffic lane. Leave it two minutes.
- The water beads or sits as a clear droplet: the sealer is working. Nothing to do.
- The water flattens out and spreads: the sealer is thinning. Book a reseal in the next six to twelve months.
- The water soaks in and leaves a dark patch: the sealer is gone there and the concrete is absorbing whatever lands on it. Reseal now.
Test three or four places. Sealer wears unevenly - the lane in front of a kitchen bench fails years before the corner of a spare room - and the whole floor is resealed together.
The other signs
- Stains that did not used to happen. Coffee, oil or wine leaving a mark where it used to wipe away.
- Dull patches in traffic lanes while the edges keep their sheen.
- A floor that looks dirty however you clean it, because dirt is sitting in open concrete.
- On a grind and seal floor, flaking or lifting at the edges. That is the coating letting go.
If you are not sure, send us photos and the result of your water test. If the floor is not due, we will tell you to leave it.
The reseal matrix
Intervals in years. Find your finish, then your setting, then your traffic.
| Finish | Light traffic | Moderate | Heavy |
|---|---|---|---|
| Grind and seal, indoor | 4-5 | 3-4 | 2-3 |
| Grind and seal, outdoor or wet | 3-4 | 2-3 | 2 |
| Honed and sealed, indoor | 6-8 | 5-6 | 3-4 |
| Honed and sealed, outdoor or wet | 4-5 | 3-4 | 2-3 |
| Polished to 800, indoor | 8-10 | 6-8 | 4-6 |
| Polished to 1500, indoor | 10-12 | 8-10 | 5-7 |
- Light: bedrooms, formal living, a holiday house used a few weeks a year.
- Moderate: a normal family home - kitchen, living, hallways, the path from the back door.
- Heavy: commercial floors, busy entries, anywhere sand is walked in daily. Beachside houses sit here more often than owners expect.
Three things shorten the interval more than anything else. Sand and grit underfoot - abrasion wears sealer, not footsteps. Sun - UV degrades sealer, so north and west rooms with big glazing go first. And cleaning - the wrong products strip sealer in months. The matrix tells you when to start testing; the water test tells you what is actually happening.
What a reseal involves
For a honed or polished floor, a reseal is a one-day job on a typical house, with one person on site.
- Clear the floor. Furniture out of the area being done - we can work in halves.
- Deep clean. A pH-neutral clean to lift residue, or the new sealer will not bond.
- Light abrasion where needed, to even out worn traffic lanes.
- Apply sealer. Flooded on, left to dwell, excess wiped back before it dries. Leaving excess to dry is what causes blotching.
- Cure, then burnish to work the sealer in and lift the sheen.
Foot traffic after 24 hours. Keep it dry for 72 hours, and no furniture or rugs for 48.
A grind and seal floor is different: the old coating is abraded and two new coats go down. Expect two days. If the coating has failed badly - widespread flaking - it may need stripping, which costs considerably more. That is the main reason not to leave a coated floor too long.
A reseal does not remove scratches, fill new holes or change the exposure. Those need grinding, a different job at a different price. If your floor needs more than a reseal, we say so before we start.
Care between reseals
Use
- pH-neutral cleaner and warm water, with a wrung-out microfibre mop.
- Doormats at every entry, and a mat under any wheeled chair.
- Felt pads under furniture legs.
- Sweep or vacuum before mopping. Grit dragged around under a mop is what wears the sealer.
Avoid
- Anything acidic: vinegar, citrus cleaners, bathroom and tile products.
- Eco and natural cleaners without checking the pH - many are citrus or vinegar based.
- Abrasive cleaners, scouring pads and steam mops.
- Wax-based mop products, which build a film that traps dirt.
- Rubber, latex and PVC-backed mats, which can mark sealed concrete permanently.
- Spills left to stand, and tape stuck directly to the floor.
In the first few weeks after a reseal, use pH-neutral cleaner only. Excess sealer rises as a faint oily film that can look like the floor is not clean. It passes after ten to fifteen washes.