The Brief
In early September 2025, we were contacted by the managing agent of a commercial business park on the outskirts of Bryanston. The property housed twelve tenants — a mix of light industrial units and professional offices — and the landlord had decided to invest in a full exterior refresh ahead of lease renewals.
The brief was straightforward: restore the precast boundary walls along all three street-facing sides of the property to a standard that matched the freshly painted buildings inside. The walls hadn't been cleaned in approximately four years.
On-Site Assessment
Before any equipment left the yard, we walked the full perimeter with the managing agent. The assessment revealed three distinct problem zones:
- North-facing wall (main road frontage, ~120m): Heavy black lichen colonisation, particularly in the shaded sections beneath mature trees. Significant efflorescence along the bottom two courses of panels. The lichen had penetrated into the surface texture, meaning a standard wash wouldn't cut it — dwell-time chemical pre-treatment was essential.
- East-facing wall (~90m): General algae, road grime, and one section with faded graffiti tags approximately 1.5m long. The graffiti was old — likely over two years — which typically means deeper paint penetration into the concrete.
- West-facing wall (~130m): The cleanest section. Primarily road dust and green algae. Good drainage at the base had prevented the moisture-related issues seen on the north face.
We always photograph and document the full perimeter before starting. This protects both the client and our team — any pre-existing cracks, staining, or damage is on record before our equipment goes anywhere near the walls.
Our Treatment Approach
Phase 1 — Chemical Pre-Treatment
The north-facing wall received a full application of our biodegradable biocide formula. This was applied the afternoon before pressure washing began and left to dwell overnight. The product works by breaking down the cellular structure of lichen and algae at the root level — without this step, you can blast a wall clean only for the surviving root system to regenerate within weeks.
The graffiti section on the east wall received a separate specialist paint-stripping agent, also left to penetrate for a minimum of four hours before washing.
Phase 2 — High-Pressure Washing
We used our commercial cold-water pressure washing unit running at 3 000 PSI for the heavily contaminated sections, dialling down to 1 800 PSI on the smoother, less contaminated panels of the west wall. Working top to bottom, section by section, we flushed the loosened biological material and chemical residue off the surface completely.
All runoff was channelled to the property's stormwater drainage. We pre-wetted all landscaping and garden beds bordering the walls before starting, and rinsed them thoroughly after each section was completed.
Phase 3 — Graffiti Finishing
After the initial wash, the graffiti area showed 80% removal — a solid result given the age of the tags. A second application of stripper and a targeted re-wash brought the remainder to near-invisible levels. On textured precast, absolute perfection is rarely achievable with very old paint, but the result was indistinguishable from two metres — the viewing distance that matters for street appeal.
The Result
By mid-afternoon on day three, the full perimeter was complete. The managing agent walked the walls with us before sign-off and described the result as "night and day." The black lichen and green algae were entirely gone. The efflorescence on the north wall had been dramatically reduced — some residual ghosting remained in the deepest-stained sections, which we flagged as a moisture source issue rather than a cleaning issue (something to address with a penetrating sealer).
The graffiti area passed the client's sign-off. Street-facing curb appeal was transformed.
Following the clean, the managing agent reported that two prospective tenants who had previously passed on units specifically cited the improved exterior condition as a factor in reconsidering the property.
Key Takeaways for Commercial Properties
- Four years between cleans on a high-traffic commercial perimeter is too long. We recommend annual professional cleaning for business parks.
- Graffiti removal success decreases significantly with age. Faster response = better outcome.
- North- and east-facing walls in Johannesburg accumulate biological growth significantly faster than south- and west-facing ones. Factor this into your maintenance schedule.
- A clean perimeter wall isn't just cosmetic — it signals to tenants and visitors that the property is actively managed.
Managing a commercial property in Sandton or the northern suburbs? Get a free assessment — we handle projects of all scales.