Residential Render, Brick and Patio Cleaning - Northampton (February 2026)

In February 2026, we completed a series of full residential exterior cleaning jobs across Northampton covering three different surfaces: painted render with dark vertical streaking, a Victorian red brick front garden wall, and Indian sandstone patio flags. Each surface needed a different method, but the underlying approach was the same - break down organic growth at root level, rinse cleanly, and apply a biocide to slow regrowth.

These jobs are typical of what we do across Northamptonshire. Homeowners often book us for one service and ask about another while we are on site - render clean turns into render plus patio, brick wall restoration gets added to a roof clean. Most properties benefit from a coordinated approach rather than spreading individual services across several visits.

Project Summary

• Location: Northampton, Northamptonshire (various residential properties)
• Date: February 2026
• Surfaces cleaned: Painted render (three-storey gable ends and full facades), Victorian red brick boundary walls, Indian sandstone paving
• Main issues: Dark vertical streaking on render, heavy algae/organic staining on brick, green algae and biofilm on natural stone patios
• Methods used: Sodium hypochlorite soft washing, low-to-medium pressure washing with rotary surface cleaners, DDAC biocide treatment

Work Completed

Render Cleaning - Painted Render Streaking Removal

The render projects involved three-storey rendered townhouses where vertical dark streaks had developed across gable ends and facades. The streaking was a mix of atmospheric soiling, algae colonisation, and water runoff staining from parapet lines and window sills.

We applied a controlled sodium hypochlorite cleaning solution to the rendered surfaces, allowed sufficient dwell time for the solution to break down the organic component of the staining, and rinsed carefully at low pressure to avoid driving water behind the render layer. Once the walls were clean and dry, we applied a DDAC biocide treatment to inhibit algae regrowth for 4 to 5 years.

The result is a clean, uniform cream finish across the full facade - visible in the before/after pairs in the gallery. Streaking that took years to develop is removed in a single day.

Victorian Brick Wall Restoration

The brick wall job was a front garden boundary wall on a Victorian terraced house. Years of black algae and organic staining had left the red brick looking dark and neglected. The mortar was in good condition, which meant we could use medium pressure washing safely.

We used a rotary surface cleaner at controlled pressure to lift the organic staining from the porous red brick surface without eroding the mortar joints. After the bulk of the staining was removed, we applied a DDAC biocide treatment to prevent the algae returning. This approach is safe on modern mortar but we would never use it on heritage lime mortar - for listed buildings we switch to soft wash only.

Sandstone Patio Cleaning

Indian sandstone patio flags heavily colonised with green algae and biofilm - the classic problem on natural stone paving in UK gardens. Sandstone is porous, holds moisture, and sits at ground level in partial shade. Algae builds up fast.

We applied a sodium hypochlorite cleaning solution to kill the algae at root level, allowed dwell time, then pressure washed the slabs with a rotary surface cleaner for even coverage. Rotary cleaners distribute water across the surface at a controlled pressure so you do not get the striping marks a single jet leaves. After cleaning, a DDAC biocide was applied to slow regrowth - sandstone patios benefit hugely from biocide treatment because they sit in exactly the conditions algae loves.

The Challenge

The common thread across all three surfaces was organic growth - algae, lichen, biofilm - but each surface needed a different approach. Render is fragile and cannot take high pressure. Modern brick mortar can handle controlled pressure washing. Sandstone patios respond best to rotary cleaners after a chemical pre-soak. Using the wrong method on any of them would cause damage: high-pressure jets on render drive water behind the surface, aggressive pressure on heritage brick erodes mortar, and single-jet pressure washing on sandstone leaves streak marks.

The other challenge was getting uniform results. A half-cleaned facade looks worse than an untouched one, so all three projects required careful attention to coverage, consistent dwell times, and methodical rinsing.

Results

• Render streaking fully removed, consistent cream/sand finish restored across all elevations
• Victorian brick wall restored from dark staining to warm red brick colour
• Sandstone patio back to original warm buff tone, algae and biofilm removed
• DDAC biocide applied on all three surface types - 4 to 5 years of regrowth protection
• No damage to mortar, render, or stone surfaces

Related Services

• Render Cleaning - method detail, render types, pricing from £350
• Pressure Washing - patios, driveways, block paving, from £150
• Exterior Cleaning in Northampton - all residential services