A driveway takes more abuse than any other surface at your house. Cars leak, fertilizer gets tracked across it, sprinklers spray it every morning, and a Maryland winter throws salt and freeze-thaw at it on top of all that. By the time people call me, the stain that’s bothering them has usually been there a while.
The first thing I want you to know is that oil stains and rust stains are two completely different problems. A regular pressure wash won’t fix either one on its own. Here’s how we handle each, and what kind of results are realistic.
Oil stains
Oil soaks down into concrete, which is why plain water, even at high pressure, just slides over it. We pre-treat oil spots with a degreaser and give it time to break the oil down before we wash. Hot water helps a lot here too, because it loosens oil far better than cold.
What to expect
Fresh and moderate oil spots usually come out or fade a lot. Old, dark stains that have been baking into the concrete for years often lighten a great deal but may not disappear completely. I’ll tell you that before we start, so you know what you’re paying for.
If you just spilled oil
Don’t hose it. Blot up what you can, then cover it with kitty litter or sand and let it sit to absorb as much as possible before you sweep it up. The less oil that soaks in, the easier it is to get out later.
Rust stains
Those orange marks on your driveway or patio usually come from one of three places:
- Fertilizer. Many lawn fertilizers contain iron. Granules bounce onto the concrete, get wet, and leave little orange dots or splotches.
- Irrigation or well water. If your sprinklers run on water with a lot of iron in it, you’ll see orange staining wherever the spray hits.
- Metal sitting on concrete. Patio furniture, planters, grills and tools can leave rust rings behind.
Pressure won’t touch rust. It takes a rust remover that dissolves the stain chemically, and it has to be the right product for concrete. Some of the strong acids sold for this can etch the surface and leave you with a different-looking patch than the one you started with, which is why I’d rather handle it than have you experiment. We do rust removal for homes and businesses.
If fertilizer is the cause, the stains will keep coming back unless you sweep or blow the granules off the concrete after every application. That one habit makes a big difference.
Why driveways sometimes look striped after a wash
If you’ve ever seen a driveway with light and dark lines across it after someone cleaned it, that comes from using just a wand held too close to the concrete. We clean flat surfaces with a surface cleaner, a spinning attachment that cleans evenly across the whole area, and then go over the edges and details by hand. You get an even, consistent finish instead of stripes.
What about winter salt?
Freeze-thaw cycles and deicing salt can cause concrete to flake and pit, a problem called spalling, and the damage often shows up in March and April. A cleaning won’t repair spalled concrete. But spring is a great time to have your driveway cleaned so you can see its real condition after winter, and if you’re thinking about sealing it, cleaning comes first.
Common questions
Will pressure washing damage my concrete?
It can if it’s done wrong: too much pressure, the tip held too close, or harsh acids. Done right, with a surface cleaner and the right pre-treatments, it’s safe for driveways, sidewalks and patios.
Can you clean pavers too?
Yes. Pavers need a bit more care so we don’t wash out the sand between them. We recently cleaned a large travertine paver pool deck and kept the sand and grout intact.
How often should a driveway be cleaned?
For most homes, once a year keeps it looking good. A spring cleaning after winter is the most popular time.
Stains bugging you?
Send me a photo when you reach out and I’ll tell you honestly what I think will come out. Call us at (410) 948-0228 or contact us online. You can read more about our driveway cleaning and concrete cleaning services, which we offer across Anne Arundel, Howard and Baltimore County, including Catonsville, Millersville and Owings Mills. Businesses can see our commercial concrete cleaning page.
Frank
Owner, Professional Power Washing