The Challenge
Natural limestone and heritage paving are highly porous materials common throughout Fremantle and coastal Perth. A combination of winter shade, coastal humidity, and bore water sprinklers had allowed black algae, moss, and mineral stains to blanket 120 square metres of pool coping, entertaining patio, and driveway. The slippery surface had become a safety hazard for the owners' elderly parents and visiting grandchildren.
Our Approach
We applied an eco-friendly, biodegradable pH-neutral pre-treatment to break down deep biological algae roots without corroding the porous limestone. We then utilized a dual-nozzle 20-inch rotary surface cleaner calibrated to optimal pressure, ensuring uniform cleaning with zero zebra striping or surface gouging, finished with a high-volume soft rinse into stormwater drains.
The Result
The limestone pavers were completely revitalized, returning to their rich natural golden-buff hue. All slick green and black algae were eradicated from pool coping and timber steps, eliminating the slip hazard completely while preserving the integrity of the heritage masonry.
The Danger of Algae on Porous Coastal Pavers
Fremantle's coastal microclimate means outdoor limestone, liquid limestone, and brick pavers stay damp throughout Perth's winter. Microscopic spores of green and black algae take root in the microscopic pores of the stone, blooming into an unsightly and dangerously slippery film. Standard homeowner pressure washers often do more harm than good: using narrow spray tips at excessive PSI gouges the soft limestone, leaves permanent streaks, and blows out polymeric joint sand.
Our Gentle, Commercial Rotary Washing Approach
To protect the valuable stone, we employed our professional commercial pressure washing rig. We began by saturating surrounding garden beds and pot plants with fresh water to shield delicate foliage, then applied our biodegradable cleaning agent. Using a 20-inch rotary surface cleaner, two counter-rotating jets delivered constant, evenly distributed pressure across every square centimetre. This lifted the grime and biological growth cleanly without etching lines or loosening the pavers.
Pool Coping Detailing & Non-Slip Safety Restored
Around the swimming pool, our technicians carefully washed the bullnose coping tiles away from the water to prevent runoff from entering the pool filtration system. The transformation was dramatic: years of dark grey oxidation and green moss disappeared, revealing the original honey-coloured limestone texture underneath. The non-slip friction of the pavers was 100% restored, giving the family complete peace of mind when entertaining around the pool.
Long-Term Surface Protection for Perth Homes
Periodic high-pressure washing every 12 to 18 months prevents biological growth from permanently etching into concrete, brick, and limestone. Aspect provides full exterior hardstand cleaning across Perth, including driveways, council crossovers, patios, timber decking, and commercial parking bays.
