Many patios and driveways end up covered in small black or grey-white spots that don’t move with a brush. They are usually not dirt at all.
They’re usually lichen
Those spots are usually lichen. Lichen is a combination of a fungus and algae living together. It grips the surface of paving very tightly and grows slowly, which is why it spreads as small round spots over time.
Why they’re hard to shift
Because lichen is bonded to the surface, sweeping and a quick wash rarely remove it. Pressure washing may lighten the spots but can leave marks behind.
How they’re treated
Lichen usually needs a treatment that breaks it down, followed by cleaning. It can take some time after treatment for the spots to fade fully, depending on the product and the weather.
Could it be something else?
- Chewing gum leaves flat grey or black circles, often near doors and gates.
- Oil drips leave larger, irregular dark stains on driveways.
- Mould can appear as a darker film in very damp, shaded corners.
If you’re not sure what’s on your paving, send us a photo.
Keeping them away
Lichen likes the same damp, shaded conditions as algae and moss. Keeping paving clear of debris and letting light in helps. See why your patio goes green.
See patio cleaning and driveway cleaning, or ask for a quote.
