The white haze inside your front door in March is not dirt and it will not mop off. It is the single most avoidable damage a floor takes in this city.
Ice melt is mostly calcium chloride or magnesium chloride. Tracked in on boots, it dissolves in the snow melting off them and then dries as a salt crust on the finish. That crust is alkaline and it is abrasive, and it does two things at once: it etches the finish chemically and it grinds it mechanically as people walk over it.
The white haze people try to mop away is usually the etched finish itself, not residue sitting on top. That is why mopping does not work.
Long winters, plenty of freeze-thaw cycles, and driveways that get treated repeatedly between December and March. An entry floor in this metro sees salt on and off for four months a year, every year, which is a very different exposure from a wet boot.
The damage concentrates in the first two metres inside every exterior door, which is why an otherwise healthy floor often has one ruined patch.
Mats at every entry, and this is not decorative advice. A mat outside to knock the bulk off and an absorbent mat inside long enough for two full steps. Two steps is the specification that matters, a small mat that catches one footfall lets the second one land salt on the finish.
Then wipe up melt water rather than letting it dry. Once it dries, the salt is concentrated on the surface and the clock starts. A damp cloth in the first hour prevents nearly all of it.
Light etching sometimes comes back with a screen and recoat, which abrades the damaged top layer and puts fresh finish over it, at $2.00 – $4.00 per sq ft. That works when the damage is in the finish and has not reached the wood.
If the salt has gone through and greyed the wood itself, a recoat will not touch it and the area needs sanding back to bare wood, at $2.75 – $5.50 per sq ft. The dividing line is whether the discolouration is still there after the finish is abraded off a test patch.
Two mats and a rag by the door prevent a repair that costs several hundred dollars per entry. There is no product, finish or maintenance schedule that beats keeping the salt off the floor in the first place.
Abrading the old finish and adding a coat without sanding to wood. $2.00 – $4.00 per sq ft.
Yes. Calcium and magnesium chloride etch the finish chemically and abrade it underfoot, leaving a white haze that does not mop off because it is the damaged finish, not residue.
If it is fresh residue, a damp cloth removes it. If it does not come off, the finish itself is etched and the fix is a screen and recoat, or sanding if the salt has reached the wood.
One outside to knock off bulk, one absorbent inside long enough for two full steps. A mat that catches only one footfall lets the second step put salt on the finish.
Worse, because it soaks in rather than sitting on top. Salt damage is usually confined to the finish; urine reaches the wood and often the subfloor, and black staining there does not sand out.
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