That dark, speckled growth on your driveway is called black spot and it's one of the most stubborn driveway problems. Here's what causes it and how to get rid of it.
If you've noticed dark, almost black spots or patches appearing across your block paving or concrete driveway, you're dealing with what's commonly known as "black spot." It's one of the most stubborn and unsightly driveway problems, and it's very common in the UK climate.
What Causes Black Spot?
Black spot is caused by a fungal organism called Aspergillus niger -- a type of black mould that forms dark colonies on paving surfaces. It thrives in the UK's damp climate and is particularly prevalent in areas with poor drainage, heavy shade, or where organic debris accumulates.
Unlike algae and moss, which sit relatively loosely on the surface, black spot fungus has fine root structures (hyphae) that penetrate into the surface of the paving. This is why it's so difficult to remove completely with ordinary cleaning methods -- removing what's visible on the surface doesn't address the root growth within the block.
Why Is It So Hard to Remove?
Standard pressure washing will remove the visible dark staining, but without treating the underlying fungal growth, black spot will return within weeks or months -- often looking exactly the same as before, or worse. This leads many homeowners to believe that cleaning "didn't work," when in fact the cleaning addressed only the symptom rather than the cause.
The Professional Approach
Effective black spot removal requires a combination of specialist biocidal treatment and thorough pressure washing. The biocide needs to be applied at the correct concentration and allowed to dwell on the surface for long enough to penetrate and kill the fungal growth at its root. Only then should pressure washing be carried out to remove the dead organisms.
In severe cases, a second biocidal treatment after the initial clean may be necessary to achieve a fully clean result.
Prevention
After cleaning, a quality block paving sealant will significantly reduce the likelihood of black spot returning. The sealant fills the microscopic pores in the surface where the fungal spores take hold, making it much harder for them to establish.
Improving drainage and reducing shade where possible will also help. Black spot tends not to thrive on surfaces that dry out quickly after rain.
Contact us if you have black spot on your driveway -- we have the specialist equipment and products to deal with it properly.
Written by the Tamworth Brighter Drives team
With over 10 years of experience cleaning and restoring driveways and patios across Tamworth and the Midlands, our team shares practical knowledge drawn from thousands of real jobs.
Need your driveway or patio cleaned?
Get a free, no-obligation quote from Tamworth's #1 driveway and patio cleaning specialists. We cover Tamworth, Lichfield, Sutton Coldfield, Birmingham and the wider Midlands area.