A basement floor coating turns a dusty, stained slab into a bright floor that wipes clean. Basements are the one place moisture decides everything, so we test the slab before we quote a system, diamond grind it, repair the cracks, and then coat it in full flake, partial flake or solid color polyaspartic.
By Rob Diederich, owner · Updated
First step
Moisture test
Prep
Diamond grind, CSP 2–3
Finishes
Full flake, partial flake, solid
Quote
From photos, within 24 hours
Basement floor coating at a glance
Before anything else
A moisture check: a calcium chloride test (ASTM F1869) or an in-slab humidity probe (ASTM F2170)
Prep
Full diamond grind to about CSP 2–3 with dust extraction, edges included
Repairs
Cracks, pits and old patches filled; old paint or sealer ground off
Basement slabs sit in the ground, and many older ones were poured without a vapor barrier. Water vapor moving up through the concrete pushes on a coating from below, and that's the most common reason basement coatings fail. So we test before we quote. A slab that passes gets our standard system; one that's borderline gets a moisture-tolerant base coat; one with an active leak or standing water needs the water fixed first, and we'll tell you so.
White powder on the floor? That's efflorescence: salts left behind by water moving through the concrete. It's a sign to test, not a reason to give up. More in cleaning concrete floors.
1Diamond grindThe whole floor is ground with diamond tooling and vacuumed. This opens the concrete so the coating has something to bite into. No acid etching.
2Repair cracksCracks, pits and spalls are filled and ground flush so they don't show through the finished floor.
3Base coatA base coat goes down over the ground concrete. This is the layer that bonds to the slab.
4Broadcast flakeFlake is thrown into the wet base coat until it covers the floor, then the excess is scraped and vacuumed off.
5Clear topcoatA UV-stable clear topcoat locks in the flake, sets the texture for grip and takes the wear.
Illustrations, layers exaggerated for clarity. Most garages are done in a day; parking time depends on the system.
Before we start, everything comes off the floor, and we set up ventilation for the install. Sunken sections, like a slab that dropped near a floor drain or a sump, get lifted first, because a coating can't level a floor.
What it costs
Nationally, professional coatings run about $4 to $12 per square foot installed (HomeGuide). Your price depends on the size, the repairs and the finish, and comes from photos of the floor. See the coating cost guide.
Often, yes. We test the slab first. Damp from vapor moving through the concrete can usually be handled with a moisture-tolerant base coat. An active leak, standing water or a floor that floods needs the water fixed first, because no coating holds back water under pressure.
Will a coating stop my basement floor from sweating?
It can't change the humidity in the room, so condensation can still form on a cold floor in summer. A dehumidifier handles that. What a coating does is keep spills, stains and dust out of the concrete and make the floor easy to wipe up.
Do I need to empty the basement before you coat the floor?
The area being coated has to be empty: the whole floor is ground, repaired and coated in one go. Furnaces, water heaters and other fixed equipment stay; we coat around them.
How do you test a basement floor for moisture before coating it?
With a calcium chloride test (ASTM F1869) or an in-slab humidity probe (ASTM F2170), which give a real number instead of a guess. That number decides whether the floor gets our standard base coat, a moisture-tolerant one, or needs a water problem fixed first. Taping a square of plastic to the floor gives you a hint at home, not a number.
How much does it cost to coat a basement floor in Green Bay?
Nationally, professional floor coatings run about $4 to $12 per square foot installed (HomeGuide). Where a basement lands in that range depends on its size, what the moisture test shows, crack repair and any old paint to grind off. We price from photos of the floor, by text within 24 hours, and confirm the base coat with a moisture test before we start.
Can you coat around a sump pit and floor drain?
Yes. The coating runs right up to the sump basin and floor drains, the lid and grates still lift out, and water still flows where it should. If the slab has dropped around the pit or drain, it gets lifted first, because a coating follows the floor and can't level it.
Should I put carpet or a coating on my basement floor?
If the basement has ever been damp, a coating. Carpet holds moisture and odors and is ruined by a backed-up drain or a failed sump pump, while a coated floor just gets wiped dry. Carpet is softer and warmer underfoot, so plenty of people coat the whole floor and put area rugs in the family room.
Can you coat the floor in a finished basement?
Yes, as long as the floor itself is bare concrete. We grind with dust extraction and coat right up to the walls. Baseboards are best taken off before we come and put back once the coating has cured, so the coating runs underneath; if yours can't come off, tell us and we'll work along them.
Do I need to pull up old carpet or tile before you coat?
Yes, the coating has to go on bare concrete, so carpet, pad, tack strips and loose tile come up first. Old black tile adhesive is a different story: it can contain asbestos, so it gets tested before anyone disturbs it, and we don't grind it off. The floor prep guide explains the options.
Should I coat my basement floor before or after waterproofing or an egress window?
After. Interior waterproofing usually means cutting out and re-pouring a strip of floor along the walls, and an egress window brings dust and debris through the basement. Coating last means the new concrete gets ground and coated with the rest of the floor, once it has cured at least about a month and passed a moisture test.
Can you coat a basement floor that has in-floor radiant heat?
Usually, yes. Grinding takes off only the thin top layer of the slab, and a cured coating handles the warmth. Mention the heat when you send photos: we'll ask you to turn it down before the install and bring it back up slowly afterward, and if the tubing might sit close to the surface, we check before we grind.
Does a basement floor coating smell, and do we need to leave the house?
There's a noticeable smell while the coating goes down and for a while after, so we set up ventilation for the install, and it fades as the coating cures. You don't need to move out, but pets and anyone sensitive to odors are better off out of the house on install day.
How long does it take to coat a basement floor?
Usually a day, like a garage. A large basement, lots of crack repair or old paint to grind off can add time, and we'll tell you up front from your photos. You can walk on the floor within a few hours, and we'll tell you when furniture can go back.
Why does paint keep peeling off my basement floor?
Usually moisture. Water vapor moving up through the slab pushes on a thin film of paint sitting on smooth, unground concrete until it bubbles and lets go. We grind the old paint off, test the slab, and bond the coating into the ground concrete with a base coat matched to what the test shows.
How long does a basement floor coating last?
Many years when the slab is tested and prepped right. Cost guides cite 10 to 20 years or more for professionally installed polyaspartic floors in garages, and a basement sees no hot tires or road salt. Moisture is what shortens a basement coating's life, which is why we test first, and the written warranty on your quote spells out what's covered.
