Full House Render Cleaning - Northampton (September 2024)

One of our exterior cleaning jobs in September 2024 was a full house render job for a residential property in Northampton. Across several elevations, green and black algae staining covered the rendered walls. Even though there was nothing wrong with the structure, the property had a dull, unsightly appearance. Using soft wash methods and a biocide treatment, we restored the render to a clean, uniform finish.

The project, at a glance

• Location: Northampton
• When: September 2024
• Property type: Residential detached
• What was the main issue: Green and black algae on the render
• How did we address it: Soft wash + biocide treatment

What we were running up against

Most algae growth was found on the shaded elevations of the property. Not a surprise for us, though. Biological growth thrives in areas with reduced light and high moisture retention. Beneath the eaves, there was a visible streaking down the render from runoff. Organic growth was also trapped within the grain of the textured render surface. Removing it was way harder than removing it from a smooth finish. With green algae on the shadier sides and black biofilm spreading across other areas, the reality was pretty brutal: the property looked uneven and patchy, no matter which angle you took.

How did we handle it

We started by examining the render type and the severity of staining on every elevation. Because of the textured finish, we had to adjust the pressure carefully. Cleaning without damaging was also our goal. Using a cleaning solution, we applied it at low pressure across all affected elevations. Dwell time was key. We allowed the treatment enough time to break down the algae and biofilm.

Working top to bottom, we meticulously rinsed every elevation—no streaking or residue left behind. Paying attention to the most minute detail, we cleaned around windows, soffits, and downpipes. We followed the cleaning with the application of a biocide to all elevations. It inhibits regrowth and ensures protection for 4–5 years. Between washes, the render will stay cleaner longer.

The Results

Across all elevations, the render returned to its original colour. Talk about efficiency. The most impressive results were on the once-shaded sides, which were covered by stubborn algae and were now clean and consistent with the rest of the property. With our biocide treatment, the homeowner was expected to see the render remain clean for several years before a retreatment would be necessary. Done.

Related Services

• Render Cleaning