Quick verdict
Uneven concrete catches a surface cleaner on every raised edge, so the ones that work hold their nozzle height, lift easily and let the operator see the bumps coming. The Karcher 15-inch holds height best; the Westinghouse 15-inch is lightest to lift; the Greenworks 15-inch includes the extension that keeps the operator upright. Match the cleaner to the washer PSI and fill the worst dips before washing.
Karcher 15-Inch Surface Cleaner for 2,600 to 3,200 PSI
A surface cleaner on uneven concrete has to keep its nozzles at a fixed height as the deck rides over lips and dips, and the Karcher 15-inch is built with a skirt and spinner that hold that height to eliminate streaks. Two spinning nozzles clean a 15-inch path, it fits any wand with a quarter-inch quick connect and Karcher rates it for 2,600 to 3,200 PSI washers.
The best surface cleaners for uneven concrete: Karcher 15-inch, Westinghouse universal 15-inch at 4 pounds and Greenworks 15-inch with extension, compared on nozzle height control, weight and fit.
The picks at a glance
| Tool | Best for | Score /100 | |
|---|---|---|---|
| Karcher 15-Inch Surface Cleaner for 2,600 to 3,200 PSI | Best for Uneven Slabs | 8.8 | Check price |
| Westinghouse Universal 15-Inch Surface Cleaner, 3,400 PSI | Lightest 15-Inch for Gas or Electric | 8.5 | Check price |
| Greenworks 15-Inch Surface Cleaner with Extension | Best With Extension Wand | 8.4 | Check price |
The picks, reviewed
Karcher 15-Inch Surface Cleaner for 2,600 to 3,200 PSI
A surface cleaner on uneven concrete has to keep its nozzles at a fixed height as the deck rides over lips and dips, and the Karcher 15-inch is built with a skirt and spinner that hold that height to eliminate streaks. Two spinning nozzles clean a 15-inch path, it fits any wand with a quarter-inch quick connect and Karcher rates it for 2,600 to 3,200 PSI washers.
Reasons to buy
- Holds nozzle height over bumps
- Two spinning nozzles
- Universal 1/4-inch connector
- Karcher build
Reasons to avoid
- Needs 2,600 PSI or more
- No wheels
- Skirt wears on rough concrete
Westinghouse Universal 15-Inch Surface Cleaner, 3,400 PSI
At 4 pounds the Westinghouse 15-inch is light enough to lift over a step or a raised slab edge, which uneven concrete asks every few feet, and it is rated to 3,400 PSI for gas and electric washers on a quarter-inch connector. Westinghouse names decks, patios and driveways as its jobs.
Reasons to buy
- 4 pounds
- Rated to 3,400 PSI
- Universal connector
- Low price
Reasons to avoid
- No wheels
- Plastic housing
- Needs a strong washer to spin well
Greenworks 15-Inch Surface Cleaner with Extension
The Greenworks 15-inch includes an extension so the operator stands upright behind the cleaner, which on uneven concrete means seeing the lips before the deck hits them. It fits most washers on a quarter-inch quick connect and carries a three-year warranty.
Reasons to buy
- Extension wand included
- Three-year warranty
- Universal connector
- Good value
Reasons to avoid
- No wheels
- Modest build
- Best on electric washers
Why uneven concrete is hard on surface cleaners
A surface cleaner is a round deck with spinning nozzles that cleans a wide path evenly, as long as the deck stays flat on the concrete. On an old driveway with heaved slabs, spalled edges and dips, the deck tilts on every bump, one nozzle lifts and the result is a streak. The cleaners that work on uneven concrete hold their nozzle height with a skirt, weigh little enough to lift over a raised edge every few feet and keep the operator upright where the bumps can be seen. The three here are 15-inch attachments that fit any washer with a quarter-inch quick connect.
This guide is built from the published specifications of each product and from recurring owner feedback. We have not run these products ourselves.
How the three compare
| Cleaner | Width | Weight | Pressure | Extras |
|---|---|---|---|---|
| Karcher 15 | 15 in | Moderate | 2,600 to 3,200 PSI | Height-holding skirt |
| Westinghouse 15 | 15 in | 4 lb | Up to 3,400 PSI | None |
| Greenworks 15 | 15 in | Moderate | Electric and small gas | Extension wand |
Karcher 15-inch: holds its height
Karcher built this cleaner to keep two spinning nozzles at a fixed height from the surface, which is the design detail that stops streaks when the deck rides a lip, and it cleans a 15-inch path on any wand with a quarter-inch quick connect. It wants a washer of 2,600 PSI or more, which is a 3,000 PSI electric or a gas machine. On rough concrete the skirt wears, and it is the cleaner that leaves an even finish on a heaved slab.
Westinghouse 15-inch: lift it over the edge
At 4 pounds the Westinghouse is the one to lift over a step or a raised slab edge without thinking, and it is rated to 3,400 PSI for gas and electric washers. The plastic housing is adequate, it spins happily on a 2,000 PSI electric, and the price is low. On a driveway of many small slabs it is the practical choice.
Greenworks 15-inch: see the bumps coming
The Greenworks includes an extension wand, so the operator stands upright behind the cleaner and sees the raised edges before the deck reaches them, which on uneven concrete is half the battle. It carries a three-year warranty and fits most washers. It is best on electric and small gas machines.
Cleaning uneven concrete well
Sweep first and fill the worst dips and cracks with patching compound a week before washing, which fixes the cause. Walk the cleaner slowly in overlapping passes, lift it over lips rather than dragging, and make a second pass at 90 degrees to the first to remove any streaks. Finish the edges and steps with the wand. Rinse toward the drain, and seal the concrete once dry so the next wash is easier.
Which one should you buy
Buy the Karcher 15-inch for the most even finish on heaved slabs with a strong washer. Buy the Westinghouse 15-inch for the lightest cleaner to lift over edges. Buy the Greenworks 15-inch for the extension that keeps the operator upright.
How we research
This guide is built from the published specifications, manuals and warranty terms of each product and from recurring owner feedback. We have not run these products ourselves; where a maker does not publish a figure we say so rather than guess.
What to look for
Nozzle height control
A skirt and spinner that hold height over bumps is what stops streaks on uneven slabs.
Weight
Uneven concrete means lifting the cleaner over edges every few feet. Four pounds lifts; ten does not.
Pressure match
Surface cleaners need enough pressure to spin. Check the rating against the washer; most want 2,000 PSI or more.
Extension
Standing upright behind an extension wand lets the operator see raised edges before the deck hits them.
Our verdict
Uneven concrete catches a surface cleaner on every raised edge, so the ones that work hold their nozzle height, lift easily and let the operator see the bumps coming. The Karcher 15-inch holds height best; the Westinghouse 15-inch is lightest to lift; the Greenworks 15-inch includes the extension that keeps the operator upright. Match the cleaner to the washer PSI and fill the worst dips before washing.
FAQs
The deck tilts on a bump and one nozzle rises off the surface. Cleaners with a height-holding skirt, a slower walk and a second pass at 90 degrees fix it.
A 12 or 15-inch cleaner spins on 2,000 PSI electrics. The Karcher wants 2,600 PSI or more; the Westinghouse and Greenworks work on less.
No. The round deck misses about an inch at walls and steps, which the wand finishes.
Yes, slowly. Cracks and spalls catch the skirt; lift over them rather than dragging.