Those stubborn black spots on your patio are not dirt, and they are not going anywhere with a hose or a jet wash. They are lichen, a living organism that roots down into the stone, and the only way to clear them for good is to kill them at the root and lift them out with a low-pressure soft wash. At Outdoor Butler, the outdoor cleaning specialists across Orihuela Costa, Torrevieja and the Costa Blanca, we remove black spot properly and leave your paving genuinely clean. Ask for your free, no-obligation quote: clear prices, no hidden fees.
If you have scrubbed, bleached and jet washed and the spots keep coming back, you are not doing it wrong. You are using the wrong method for what these marks actually are. Here is what they are, why they return, and how they are removed for good.
What are the black spots on my patio?
The black spots are lichen, not dirt or mould. Lichen is a tough little organism (part fungus, part algae) that anchors itself to porous surfaces like natural stone, concrete and terracotta by sending root-like filaments down into the pores of the slab. That is why they feel flat and welded to the surface rather than sitting on top of it. On the Costa Blanca they take hold most on north-facing and shaded terraces, where the surface stays damp for longer.
Why jet washing does not remove black spots (and often makes it worse)
A pressure washer blasts away the surface grime and the visible top of the lichen, so for a day or two the patio looks cleaner. But the roots are still buried in the stone, untouched, and they simply grow back. Worse, high pressure erodes the surface of the slab and opens up the pores, leaving it rougher and more absorbent than before. That means it holds moisture more easily and the lichen returns faster and more aggressively than it did the first time. Blasting harder is not the answer; it is the reason the problem keeps getting worse.
Why bleach and vinegar are not the fix either
Household bleach and vinegar look like they work because they lighten the spots for a short while, but they do not penetrate deep enough to kill the lichen at the root, so it grows back. Both are also acidic or corrosive enough to eat into the mineral content of natural stone, sandstone and some terracotta, dulling the colour and pitting the surface. On the porcelain and natural stone that is so common on Costa Blanca terraces, that trade-off is not worth it.
How black spots are actually removed
The method that works is patient, not powerful. This is the approach a professional uses, and the same one you can follow with a proper product:
- Apply a specialist black-spot biocide. A dedicated lichen and algae treatment is applied to the dry paving and left to dwell, usually for several hours, so it soaks in and kills the organism at the root rather than just the surface.
- Let it do the work. The biocide keeps working after treatment. Dead lichen often lifts gradually over the following days and weeks as the weather washes it away, so the patio keeps improving after we leave.
- Finish with a low-pressure soft wash. Instead of blasting the stone, a gentle rinse clears the dead growth without damaging the surface or opening the pores. This is the opposite of jet washing and it is what protects the slab.
- Treat stubborn areas again. Deep-rooted lichen can need more than one round. A second treatment a little later finishes off anything the first pass did not fully kill.
How to stop black spots coming back
Once the lichen is gone, keeping it away is about denying it the damp, shaded, debris-fed conditions it loves. Sweep leaves and organic debris off the terrace regularly, keep drainage clear so water does not sit, and cut back overhanging plants that keep an area in permanent shade. On north-facing terraces that go green and black every winter, a periodic preventative biocide treatment stops the regrowth before it becomes visible again. This is exactly the kind of upkeep a regular professional outdoor cleaning visit is built around.
The Costa Blanca angle: porcelain, terracotta and north-facing terraces
Costa Blanca terraces are mostly porcelain, natural stone or terracotta, and each behaves differently under treatment, which is why a one-size blast so often backfires. Terracotta is porous and drinks in both the lichen and any harsh chemical you throw at it; porcelain is dense but its textured, anti-slip finish traps spores in every ridge. Add the shaded, north-facing corners that stay damp through winter and the odd calima dust film that people mistake for staining, and you have the perfect conditions for black spot. Treating it correctly for the surface is the difference between a patio that stays clean and one that is black again by next spring.
Frequently asked questions
What actually are the black spots on my patio?
They are lichen, a living organism that roots into porous stone, concrete and terracotta. They are not dirt sitting on the surface, which is why scrubbing and jet washing do not shift them for long.
Does jet washing remove black spots?
Only the visible top, and only briefly. The roots stay in the stone and grow back, and the high pressure roughens the surface so the lichen actually returns faster. Killing it at the root with a biocide is what works.
Will black spots damage my patio?
The lichen itself is slow to cause structural harm, but the aggressive jet washing people use to fight it does real damage, eroding and opening up the surface. Removing it gently is safer for the paving.
How long does it take to get rid of black spots?
The treatment is applied in one visit, but the dead lichen lifts gradually over the following days and weeks. Deep-rooted or long-neglected patios can need a second treatment.
How much does black spot removal cost on the Costa Blanca?
It depends on the size and surface of your terrace and how established the lichen is. We give bespoke quotes with no hidden fees. See our pricing page or ask for a free quote.
Ask for your free, no-obligation quote
Tired of black spots that come back every time you clean them? Let Outdoor Butler remove them properly in Orihuela Costa, Torrevieja and across the Costa Blanca, without wrecking your paving. We will give you a free, no-obligation quote with no hidden fees. Message us on WhatsApp at +34 644 466 783 or call +34 644 390 864 and get a patio that actually stays clean.