Establishing a patio maintenance regime can be very beneficial.  It helps retain a tile’s aesthetic, along with its performance, and reduces the need for intensive cleaning and re-sealing down the line.  Most organic stains are relatively easy to remove, especially if the patio has been sealed, but there are some that can prove more difficult, like black spot. 

Black spot originates from plants and trees and, despite its name, it can actually be black or white. The dust-like lichen microspore is carried by the wind and rain and it colonises on stonework, taking around 2-3 years to get really established below the surface.  Black spot thrives in damp, shady places, sending its tendrils or ‘hyphae’ down into the stone’s pores, searching for nutrients.  It’s a particular menace in porous stone, as its open texture enables the microspores to spread more easily, but even less porous materials like porcelain aren’t immune.  Here, the lichen can still create a slippery residue on the tile surface.  

Cleaning methods that don’t work

A pressure washer and, sometimes, a dose of household cleaner is a common go-to treatment.  However, this doesn’t work because hyphae become anchored into place below the surface.  In fact, the extra dose of water only makes conditions even better for the rampant lichen.  Also, pressure washing can damage the surface of the stone, loosen the grout and, if any protective sealer is applied, it will damage that too.

How to remove stains and preventing regrowth

A specialist, two-pronged attack is necessary in order to remove black spot stains and the microspores below the surface.  Any treatment used needs to have a bleaching action, to restore the colour of the tile or paver.  It also needs to target the hyphae below the surface.  But care should to be taken.  If a treatment is acidic, it can damage acid sensitive material and erode the grout joint.

ECOPROTEC Black Spot & Algae Remover targets organic residue, restoring appearance to natural stone, concrete, brick and porcelain, giving results in as little as two hours.  Developed to deep clean new and existing paths, patios and driveways, the treatment targets black spot, lichen, moss, algae and other stains caused by damp and slippery leaf matter.   

Three case study examples, shared by Alastair Niddrie from stone maintenance specialist, Silex UK, illustrate treatment with Black Spot & Algae Remover at sites throughout the UK:  The first – a York Stone and brick installation in Chiswick – had a build-up of green algae and black spot over 30 years.  As well as white and black staining, the lichen was creating a serious slip hazard.  At the second site in Dorset, a large limestone patio was stained with black spot, algae and dirt. The client was considering replacing the patio as repeated jet washing hadn’t resolved the issues and had damaged some areas of paving.  The third site – a courtyard in London – was also deeply stained with black spot and algae.

“These types of stains are notoriously difficult to remove and a blast with a jet wash just makes matters worse.  We’ve found a solution with Black Spot & Algae Remover. It’s formulated to cling to the surface and once absorbed, it breaks down the hyphae within the stone porosity, as well as the slippery residue on the tile surface.  A bleaching action also removes the staining, to restore surfaces to their former glory. We’re delighted with the results and now routinely use the treatment on all patio refurbishments,” explained Alastair.

Before application of ECOPROTEC Black Spot & Algae Remover, surfaces should be swept clean.  The treatment is then applied neat, using a watering can or light pressure garden spray, where it fizzes during treatment.  It should be left to act for 2-4 hours and surfaces are then hosed with clean water.  The solution can be used on dry and slightly damp surfaces and should be applied during a morning or afternoon of fair weather.  

Newly cleaned stone surfaces can be protected with ECOPROTEC Patio Sealer or Ultimate Sealer. Barrier treatment, ECOPROTEC Pre Grout Protection, is recommended for matt porcelain pavers.  Both treatments create a barrier without altering surface appearance; this prevents absorption of moisture and organic particles, reducing staining and the spread of algae, mould and black spot.  

To find out more, call the ECOPROTEC technical team on call 01823 666213 or email

To contact Silex UK, please visit, tel. 0207 504 1070 (London Office) or 01225 650122 (Bath Office) or email

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For media information and photography, please contact Angela Fitzhugh PR Ltd on tel. (01579) 673026 or email

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