Why Chemical Choice Matters
Pressure washing without the right chemistry is like washing dishes with just hot water — you'll move the dirt around but you won't truly clean. The same principle applies to precast walls. Water alone, even at high pressure, cannot penetrate the pore structure of concrete to remove biological growth at the root, dissolve efflorescence, or break down the bond between graffiti paint and the substrate.
But chemical selection has consequences beyond the wall itself. Many pressure washing operators use industrial bleach (sodium hypochlorite) at high concentrations. It's cheap, widely available, and effective at killing algae on contact. It's also highly corrosive to metal, toxic to plants at operational concentrations, and poses real risks to pets and soil ecology. On coloured precast panels, it can cause permanent, irreversible bleaching.
Our Chemistry-First Approach
We've spent years testing formulations that deliver professional cleaning results without the collateral damage. Our products are selected based on four criteria:
- Efficacy: Does it actually work on the target contaminant at practical dwell times?
- Surface compatibility: Is it safe on pigmented precast, aluminium fixtures, and sealants?
- Environmental profile: Does it biodegrade rapidly in soil and water without residual toxicity?
- Safety: Can it be used safely around established garden beds, pets, and people within normal operational distances?
The Products We Use
Biocide / Algaecide Formula
Used as pre-treatment for algae and lichen. Penetrates the biological organism's cellular structure and kills it at the root — preventing regrowth from surviving spore populations. Applied before pressure washing and left to dwell. Plant-safe at working dilutions once thoroughly rinsed. Biodegrades completely within 28 days in soil.
Efflorescence Remover (Mild Acid Formulation)
A diluted organic acid solution that dissolves salt crystal deposits without attacking the concrete matrix itself. Significantly milder than muriatic acid (the industry standard for decades), with full biodegradability and no metal corrosion risk at working concentrations. Neutralised by water rinse.
General Surface Degreaser / Traffic Film Remover
For road grime, diesel film, and general urban pollution deposits. Water-based, non-caustic, and safe for application near paved surfaces and gardens. Breaks down hydrocarbon deposits and suspends them for pressure removal. Fully biodegradable within 14 days.
Specialist Graffiti Remover (Gel Form)
Gel formulation that clings to vertical textured surfaces. Softens acrylic, enamel, and lacquer spray paint bonds for pressure extraction. Safe on concrete, brick, and most stone substrates. Not recommended near fish ponds — though we maintain a standard exclusion buffer during application.
We wet-soak all garden beds bordering the wall before applying any chemistry, and give them a thorough clean water rinse after each section. This significantly reduces any potential for product contact with plant root zones.
What We Don't Use — And Why
- Concentrated sodium hypochlorite (pool chlorine): Highly effective short-term biocide, but damages pigmented concrete, corrodes metal fixtures, and is toxic to plants and soil bacteria at common working concentrations.
- Muriatic (hydrochloric) acid: Effective on efflorescence but aggressively attacks concrete over time, damages rebar if any water ingress occurs, and generates fumes hazardous to operators and nearby occupants.
- Solvent-based degreasers: Effective on oils and grease but persist in soil, can contaminate groundwater, and are hazardous to handle in open-air residential environments.
- Unknown or unbranded industrial chemicals: We never use products that don't have documented environmental and safety data sheets. Full stop.
Common Client Questions
Is it safe for my dogs?
During active chemical application, we ask that pets be kept inside or away from the work area. By the time we've completed the wash phase and rinsed down, the chemicals are either fully flushed or diluted to below-safe-threshold concentrations. We'll always let you know when it's safe to let animals back near the wall.
Will the runoff affect my lawn or garden beds?
With our pre-soak and post-rinse protocol for adjacent garden beds, the risk is minimal. For particularly sensitive plantings — including vegetable gardens or established ornamental beds — we can discuss additional protective measures before the job.
Are you SANS/environmental regulation compliant?
Yes. All products used meet current South African environmental standards for commercial cleaning applications. We carry product data sheets on site and are happy to share them on request.
Have specific questions about our chemistry or safety protocols? Get in touch — we're happy to discuss the details before any work begins.