Full House Render Cleaning - Northampton (September 2024)

In September 2024, we completed a full house render clean on a residential property in Northampton. The rendered walls had developed significant green and black algae staining across multiple elevations, giving the property a tired and neglected appearance despite being structurally sound. Using soft wash methods and a biocide treatment, we restored the render to a clean, uniform finish.

Project Overview

• Location: Northampton
• Date: September 2024
• Property type: Residential detached
• Main issue: Green and black algae on render
• Method: Soft wash + biocide treatment

The Challenge

Algae growth was concentrated on the shaded elevations of the property, where reduced sunlight and higher moisture retention created ideal conditions for biological growth. Runoff staining beneath the eaves had left visible streaking down the render, and the textured render surface itself was trapping organic growth within the grain - making it harder to shift than it would be on a smooth finish.

The combination of green algae on the shadier sides and black biofilm developing across other areas meant the property looked uneven and patchy from every angle.

Our Approach

1. Surface assessment - We assessed the render type and the severity of staining on each elevation before selecting our cleaning approach. The textured finish required careful pressure control to avoid damaging the surface.
2. Soft wash application - A cleaning solution was applied at low pressure across all affected elevations. We allowed appropriate dwell time for the treatment to break down the algae and biofilm before rinsing.
3. Controlled rinse, elevation by elevation - Each elevation was rinsed methodically from top to bottom, ensuring no streaking or residue was left behind. Detail work around windows, soffits, and downpipes was carried out carefully.
4. Biocide treatment - After cleaning, a biocide was applied to all elevations to inhibit regrowth. This treatment provides protection for approximately 4-5 years, keeping the render cleaner for longer between washes.

Results

The render was returned to its original colour across all elevations. The difference was most noticeable on the previously shaded sides where algae had been heaviest - these went from heavily discoloured to clean and consistent with the rest of the property. The biocide treatment means the homeowner can expect the render to stay cleaner for several years before any retreatment is needed.

Related Services

• Render Cleaning