(And How Professionals Stop Regrowth)
If you’ve cleaned your patio only to find it turning green or developing black spots again within months, you’re not alone. Across Cornwall and Devon, homeowners regularly struggle with persistent patio algae and black spot regrowth, even after pressure washing.
Persistent patio algae and black spot are one of the most common reasons homeowners contact us for professional patio cleaning in Cornwall, especially when DIY cleaning has failed.
The truth is:
👉 Most patio cleaning methods remove the symptoms, not the cause.
In this guide, we explain why black spot and algae keep coming back on patios in the South West, why DIY cleaning rarely lasts, and how professional treatment stops regrowth for much longer.
What Are Black Spot & Patio Algae?
Black spot and green algae are forms of biological growth, not surface dirt.
- Black spot is a stubborn lichen that embeds itself deep into stone and concrete
- Green algae forms a slippery biofilm that thrives in damp conditions
- Moss grows in joints and shaded areas, trapping moisture
Once established, these organisms root themselves into the pores of patio slabs.
Why Patios in Cornwall & Devon Are So Prone to Regrowth
Cornwall and Devon have one of the worst climates in the UK for patio regrowth due to:
- Frequent rainfall and high humidity
- Mild temperatures year-round
- Coastal moisture and salt air
- Shaded patios with limited airflow
- Porous stone and concrete paving
This is why patios in places like Truro, Falmouth, Newquay, Exeter, and Plymouth often stay damp for long periods — creating perfect conditions for algae to return.
Why Pressure Washing Alone Doesn’t Stop Black Spot
Pressure washing removes what you can see, but it usually fails to kill growth at the root.
While pressure washing in Cornwall can improve appearance short-term, it rarely kills algae and black spot at the root — which is why regrowth is so common.
Problems with pressure washing only:
- Algae spores remain alive in pores
- Black spot lichen isn’t fully removed
- Moisture is forced deeper into slabs
- Regrowth can return in weeks or months
This is why patios often look great initially — then quickly deteriorate again.
Why DIY Patio Cleaning Rarely Lasts
DIY methods such as:
- Household bleach
- Patio cleaners from DIY stores
- Jet washing without treatment
often lead to:
- Patchy results
- Surface damage
- Faster regrowth
- Slippery surfaces
Without professional-grade treatments, algae and black spot simply recolonise the patio.
How Professionals Stop Patio Regrowth Properly
4
Professional patio cleaning focuses on eliminating the cause, not just improving appearance.
In many cases, steam cleaning patios in Cornwall is used to destroy algae and black spot using heat rather than force, delivering longer-lasting results with minimal surface wear.
For more delicate stone and older patios, soft washing services in Cornwall provide a safe alternative that treats organic growth without damaging the surface.
Why this works:
- Positions you as a specialist
- Links to a premium service
- Reinforces expertise over DIY
✔ 1. Deep Biological Treatment
Specialist biocidal treatments:
- Kill algae, moss, and lichen at the root
- Neutralise spores embedded in the surface
- Dramatically slow regrowth
✔ 2. Surface-Appropriate Cleaning
Depending on the patio, professionals may use:
- Soft washing for delicate stone
- Steam cleaning to destroy organic growth with heat
- Controlled pressure washing where suitable
✔ 3. Longer-Lasting Results
Professional treatment keeps patios cleaner for far longer — often 12–24 months depending on location.
Patios Most Affected by Black Spot & Algae
This is particularly common on shaded patios in coastal towns, where regular exterior cleaning services in Cornwall are essential to prevent recurring biological growth.
Patios at highest risk include:
- North-facing patios
- Shaded garden areas
- Coastal properties
- Older stone and concrete slabs
- Poorly drained areas
These are extremely common across Cornwall and Devon.
Patio Cleaning Across Cornwall Towns
We provide professional patio cleaning services throughout Cornwall, including:
- Truro
- Falmouth
- Newquay
- St Austell
- Penzance
- Camborne
- Redruth
- Bodmin
Patio Cleaning Across Devon Towns
We also clean patios across Devon, including:
- Exeter
- Plymouth
- Torquay
- Paignton
- Newton Abbot
- Barnstaple
How Often Should Patios Be Professionally Treated?
For most properties in Cornwall & Devon:
- Once per year for general maintenance
- Every 18–24 months with biocidal treatment
- More frequently in shaded or coastal locations
Preventative treatment is far cheaper than repeated cleaning.
Why Choose Jet Power Pressure Washing?
Jet Power Pressure Washing provides professional patio cleaning across Cornwall and Devon, using the correct method for each surface.
✔ Pressure washing, soft washing & steam cleaning
✔ Specialist algae & black spot treatments
✔ Surface-safe methods
✔ Fully insured
✔ Reliable local service
We don’t just clean patios — we stop regrowth.
Stop Patio Algae & Black Spot Regrowth Today
If your patio keeps going green or developing black spots despite repeated cleaning, professional treatment can make a lasting difference.
👉 Visit our patio cleaning services page or contact Jet Power Pressure Washing today for a free, no-obligation quote anywhere in Cornwall or Devon.
👉 Contact Jet Power Pressure Washing today for a free, no-obligation quote for patio cleaning in Cornwall or Devon.
Professional patio cleaning:
- Delivers longer-lasting results
- Improves safety underfoot
- Restores appearance
- Saves money long-term
