Resurfacing a Concrete Floor
Concrete floor resurfacing spreads a new cement layer, from a feather edge to about 1/2 inch, over a worn but sound slab, for about $3 to $7 per square foot. It fixes a powdery, flaking or stained surface. It can't fix cracks that move, a slab that has settled or heaved, or a floor that's out of level.
This is part of our concrete floor guide; the concrete resurfacing guide covers every overlay type and has the bag calculator.
Repair, level, resurface or replace?
Resurface only a slab that's sound and flat enough. A resurfacer is only as good as the concrete under it: if the slab moves, the new layer cracks with it.
Cracks, holes, spalls
Repair
Priced per repair. See concrete floor repair.
Dips, slopes, settling
Level
Self-leveling underlayment or slab lifting. See leveling.
Worn, powdery, flaking
Resurface
About $3 to $7 per sq ft.
Wide cracks, heaving, washout
Replace
About $4 to $15 per sq ft, per Bob Vila.
Judge a crack by how it behaves. One with one side higher than the other, or that has widened over a year, is structural and will come straight back through. A hairline crack that has sat still for years can be filled and resurfaced over.
How thick a resurfacer goes on
Resurfacers are the thinnest cement layer you can buy; anything that needs more than one lift is an overlay or underlayment.
Coverage per bag, by product
| Product | Bag | Covers at 1/4 in |
|---|---|---|
| Quikrete Re-Cap | 40 lb | About 16 sq ft |
| SikaQuick Resurfacer | 35 lb | 13 to 16 sq ft |
| Sakrete Flo-Coat | 40 lb | 18 sq ft |
| Quikrete Self-Leveling Floor Resurfacer | 50 lb | 21 sq ft |
The thin end, microtopping, is also sold as microcement, a polymer-modified cement coating; no standard defines either name, so compare quotes by thickness. For a floor that's uneven rather than worn, the self-leveling concrete guide compares underlayments.
How to resurface a concrete floor
Nearly every failed resurfacer traces back to prep. Five steps, in order:
- Decide if resurfacing is the right fix. A sound slab with a worn surface and hairline cracks qualifies. Heaved, settled or widely cracked slabs need leveling or replacement.
- Strip whatever is on the slab. Scrape, use hot water on water-based glue, let a soy-based mastic remover soak 45 minutes to several hours, or grind. Soft, scaling concrete comes off down to sound material.
- Profile and clean the surface. Grind or shot-blast to CSP 3 or better (SikaQuick's minimum), then pressure wash at about 2,500 psi, as Quikrete's Re-Cap and Sakrete's Flo-Coat sheets specify. Quikrete's self-leveler sheet rules out acid etching, solvents and sanding.
- Bring the slab to saturated surface dry. Cement resurfacers go onto a slab damp through its surface with no standing water. Self-leveling resurfacers want the opposite: clean, dry and primed.
- Apply within the thickness range and cure it. Work between 50 and 90°F, moist-cure the resurfacer, and expect to walk on Re-Cap in about 8 hours and drive on it in 24.
Black mastic under old flooring? Stop. Old floor tile adhesives, including black cutback in older homes, may contain asbestos. Get it identified before you grind or dry-scrape it.
Grinding an old floor
A planetary grinder takes off about 1/16 inch per pass, up to 1/8 on heavier machines, per BigRentz, along with coatings, glue and the weak top layer.
Rental
Tooling extra
Diamond tooling and the dust extractor are usually billed on top of the grinder.
Prep or finish
Ask which
Grinding as prep is a light pass; grind and polish is the finish itself and priced far higher.
Dust
Silica
Run an extractor, or the dust fills the house.
Grinding a settled slab flat doesn't fix the settling and leaves it thinner; leveling is the fix for that.
Concrete floor resurfacing cost
Pros charge about $3 to $7 per square foot, per HomeGuide; Angi and Bob Vila top out at $9. DIY material runs about $2.27 per square foot at 1/4 inch.
Interior floor, basic
$3 to $8
Per sq ft, per HomeGuide; $5 to $15 for complex work.
Decorative or stamped
$6 to $20
Per sq ft for overlays.
DIY 40 lb bag
$36.97
Covers about 16 sq ft at 1/4 inch, per the Re-Cap data sheet.
Expect 8 to 15 years before repairs, a figure from exterior-leaning cost guides. Size your floor with the concrete floor calculator and compare looks in the concrete floor finishes guide. Driveways carry cars, frost and salt, so they're covered separately in concrete driveway resurfacing cost.
Self-leveling or trowel-applied resurfacer?
Use trowel-applied on a worn floor that's already flat, and self-leveling to bury a rough interior floor under a smooth face in one pour.
Trowel-applied
To 1/2 in
Re-Cap or Flo-Coat. Follows the slab, can be broomed for grip, goes on damp. Works outdoors.
Self-leveling
To 5/8 in
Flows flat on a clean, dry, primed floor. Won't fix a slope deeper than itself.
Pro self-leveling toppings go thicker but read the exposure line: Rapid Set's TRU is "not recommended in locations subject to freezing temperatures or where deicing salts will be used," and ARDEX SD-T "is intended for interior, dry spaces."
Finishing a resurfaced floor
Sealers can go on the next day, but coatings and stains wait for a full cure, and polishing needs a thicker topping than a resurfacer.
Coat
28 days
Sakrete's Flo-Coat must be fully cured and dry before painting. See epoxy coating and garage floor repair.
Polish
3/8 in min
Rapid Set's TRU minimum for polished floors; grinding goes through a thin resurfacer. See polished concrete.
Stain
Test first
None of the four resurfacer data sheets above says whether it takes acid stain. See stained concrete.
Seal
24 hours
Quikrete's minimum wait before its sealer. See the sealing guide.
Resurfacing a basement floor
Test for moisture first, because water vapor rising through a basement slab breaks the bond. If the floor gets wet when it rains, fix the water; if it's dry, a self-leveling resurfacer usually suits it best.
Quick check: tape a 2 by 2 foot sheet of plastic to the bare floor for 24 hours and look for droplets underneath, as Rust-Oleum's coating instructions describe. The basement floor guide covers the proper tests.
Why patcher and resurfacer strength figures mislead
Resurfacer and patcher strengths come from 2 inch mortar cubes (ASTM C109) and concrete mix strengths from cylinders (ASTM C39), so they can't be compared. Cubes read higher.
Compressive, cube test
5,000 psi
Sakrete Top 'n Bond, a patcher, at 28 days, against 4,000 for its High-Strength concrete mix.
Bond strength
1,200 psi
Top 'n Bond to ASTM C882: the number that tells you a thin layer will stay put.
Each brand's products are in Sakrete mix types and Quikrete mix types.
Frequently asked questions
How thick can you apply concrete resurfacer?
From a feather edge to about 1/2 inch for cement resurfacers from Quikrete, Sika and Sakrete, and to 5/8 inch per lift for a self-leveling resurfacer. Anything thicker is an overlay or underlayment.
Can you resurface a cracked concrete floor?
Only over dormant hairline cracks, filled flush first. A crack that is still moving, or has one side higher than the other, will come straight back through the new surface.
How much does concrete floor resurfacing cost?
About $3 to $7 per square foot from a pro, and $6 to $20 for decorative or stamped overlays. Doing it yourself, a 40 lb bag of resurfacer covers about 16 square feet at 1/4 inch.
How long does a resurfaced concrete floor last?
Commonly 8 to 15 years before repairs, though that figure comes from exterior-weighted cost guides. Prep and the soundness of the slab underneath matter more than the product.
What is the difference between resurfacing and leveling a concrete floor?
Resurfacing replaces the worn top surface; leveling corrects a floor that has settled or slopes. A floor that is both worn and uneven needs both.