A surface cleaner does most of the work for you, which is exactly why the failures are technique rather than tool. Follow the seven steps below and you will get an even finish on the first attempt.
Before you start
Confirm the head is the right size for your machine’s flow — how to check. Everything below assumes the pairing is correct. An undersized machine cannot be corrected with technique.
The seven steps
1. Clear and protect
Everything off the surface. Pre-wet planting beds along the edges, because run-off carries cleaner into them. Close windows and doors you will be working under.
2. Edges first, always
A surface cleaner cannot reach the last inch against a wall, a curb or a garage threshold, and it cannot do steps. Do all of that before the main area with a wand and a 25-degree tip, or a turbo nozzle. Edges-last means flushing dirt back across slab you have already cleaned.
3. Pre-wet the whole surface
Dry concrete absorbs cleaner unevenly, which leaves faint tide marks. Thirty seconds with a wide tip prevents it.
4. Apply cleaner and let it dwell
This is where the actual cleaning happens, and it is the step people skip. Apply a concrete cleaner through the black low-pressure soap tip and leave it five to ten minutes. Do not let it dry — a dried cleaner has stopped working and may leave a residue. Re-mist if the sun is on it.
5. Connect, and let it come up to speed
Fit the head, then squeeze the trigger with the head tipped slightly off the surface so the bar is spinning before it makes contact. Starting it flat on the concrete is one of the three causes of a crescent mark.
6. Overlapping passes, one direction
Overlap by about a third of the head’s width. Keep one consistent direction across the whole area rather than changing with the light. Walk at a steady, slow pace — around a foot per second is a good starting point, slower if your flow is at the low end for the head.
Work in sections you can finish before the cleaner dries. On a hot day that may be surprisingly small.
7. Rinse in one direction
Swap back to a wide tip and push the dirty water off the surface rather than fanning it around. Uneven drying is the last chance to spoil an even clean.
The three mistakes that cause stripes
Tipping the head. Any lean puts one side of the disc closer to the surface. Four wheels mostly solve this; with three wheels, consciously keep it flat, especially over expansion joints.
Walking too fast for your flow. If the bar is turning slowly because the head is large for your machine, each spot gets hit less often and a quick pace leaves visible banding. Slow down.
A partially blocked nozzle. One nozzle doing less work shows as a regular repeating pattern. Pull the nozzles and clear them — covered in surface cleaner not spinning.
Afterwards
Run clean water through the head for thirty seconds, particularly after any chemical work. That is what preserves the swivel seal, which is the part that eventually fails. If you cleaned sand-jointed pavers, let them dry and then re-sand the joints.
The full job sequence for each surface is in the driveway guide and the patio guide.
