Pressure washing concrete: real power, and real ways to do damage.
A Michigan winter leaves a film on the driveway, road salt and grit from every plow that went by, and by July the shaded side has grown its own green. A pressure washer takes it off in an afternoon. It's also the most dangerous tool most homeowners rent, and it damages more houses than any other job on this list, so the cautions come before the technique.
How often should a driveway be pressure washed?
Once a year is plenty. A spring wash takes the winter's road salt off; a fall wash gets the front of the house looking right for the holidays. More often than yearly buys nothing on concrete.
What is the green film on concrete?
Algae and mold, growing wherever the concrete stays damp and shaded. It turns the surface dark and slick when wet, which is how people fall on their own front walk. On shaded walls the same growth does real damage over time, eating into wood decks and mortar joints, not just staining them.
Should you rent a pressure washer or buy one?
For one driveway a year, rent, and take the surface cleaner attachment with it. Owning makes sense for someone who'll also use it on a patio and a deck, with somewhere dry to store it over the winter.
How to pressure wash a driveway.
On concrete, a surface cleaner attachment lifts the dirt evenly with no zebra stripes. Keep the wand off siding and off soft stone like Lathrup limestone. High pressure slices vinyl and drives water behind the panels, where it stays and grows mold inside the wall. Walls want a low-pressure soft wash with a cleaning solution, which is a different job from concrete.
When to hand it off.
Eaves that can't be reached from the ground, or siding that might not take the pressure. Or just a half day you'd rather spend elsewhere. Pressure washing is $— added to a plan or $— one-time, the driveway and front walk.
Or never think about the driveway again. On a plan the driveway and front walk are washed on the summer visit, $—, spread across the monthly bill. Plans
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