Pressure washing or algae treatment?

Start with the surface and the cause

Identify concrete blocks, clay pavers, natural stone or another finish before choosing pressure or chemicals. Check for loose joints, damaged surfaces and existing sealer. A small trial area can show whether the proposed method changes the appearance.

Shaded paving and areas that stay wet can need repeated cleaning. Marshalls identifies shade and ponding as conditions that encourage organic growth. A wash can improve the surface without removing those conditions.

What each method does

• Brushing and a suitable cleaner: may be enough for light soiling and is a sensible starting point on compatible paving.
• Pressure washing: removes surface dirt and growth but can damage finishes or displace jointing material if the pressure and technique are unsuitable.
• Targeted treatment: may be appropriate for remaining organic staining. Product compatibility, dilution, contact time and runoff controls matter.
• Sealing: is a separate specification. It can change appearance and surface behaviour; it does not guarantee that algae will never return.

Ask how nearby plants, pets, drains and water features will be protected. Follow the cleaner label and paving manufacturer’s care guidance. Do not mix cleaning chemicals.

Compare the same scope of work

Use the pressure washing price guide for current planning rates and minimum charges. As an arithmetic example only, an assumed R45–R80/m² for a 50 m² area produces R2,250–R4,000 before separately quoted work.

A low per-metre chemical-treatment add-on is not a like-for-like comparison with a complete clean. Request a total for inspection, preparation, treatment, washing, joint reinstatement where needed and waste-water management.

Cleaning and sealing describe a different package from washing alone. Obtain its own measured quote and ask for the sealer name, preparation, curing conditions and maintenance requirements. Do not base the choice on a promised number of algae-free years without product-specific evidence.

When cleaning is not enough

Water collecting in a depression may point to drainage or paving-level problems. Loose or sinking pavers need assessment before aggressive cleaning. Ask for those repairs to be priced separately rather than concealed in a surface-cleaning promise.

Send a wide photo of the area, a close view of the growth, approximate dimensions and whether water remains after rain. Mention previous coatings. That helps establish an appropriate method and a comparable quote.