Render Cleaning
Render Cleaning
and Soft Washing Specialists
Gentle soft washing that restores rendered walls to their original finish — removing algae, green growth and staining without risking surface damage.
Safe for all render types · K-Rend & monocouche specialists · Long-lasting biocide protection
6+
Years Experience
250+
Properties Treated
Included
Biocide Protection
Yes
Fully Insured
Always
Free Estimates
Service Overview
Everything You Need to Know
What Is It
Render cleaning — also called soft washing — is the safe removal of algae, green growth, red algae, black mould, atmospheric staining and biological contamination from rendered external walls. Unlike pressure washing, soft washing uses low-pressure application of specialist biocidal cleaning solutions that kill biological growth at root level. The growth is then gently rinsed away, leaving clean render with long-lasting protection against regrowth.
Who It's For
Homeowners with any type of rendered external walls — including K-Rend, monocouche, silicone render, acrylic render, traditional sand-and-cement render, and pebbledash. If your walls have turned green, developed dark streaks running down from the roof edge, or show patches of red or black growth, professional soft washing will restore the original finish.
When You Need It
Render typically needs cleaning every 3–5 years, depending on the property's orientation and exposure. North-facing walls and those shaded by trees or neighbouring buildings develop biological growth fastest. If you can see green, black or red discolouration on your walls from the street, the growth is well-established and will only get worse without treatment.
Why Professional
Pressure washing rendered walls is risky — high pressure can force water behind the render layer, causing internal damp, and can physically damage textured finishes. Soft washing avoids these risks entirely. The biocidal solution does the work, not water pressure. It penetrates the render surface to kill spores at root level, providing months of protection rather than just surface cleaning. This is why professional soft washing delivers dramatically better and longer-lasting results than any DIY approach.
Why Green Render Gets Worse Without Treatment
Algae growth on render is progressive and accelerating. Once a colony establishes, it creates a damp microenvironment that supports faster growth. A small green patch in spring becomes a fully colonised wall by the following year.
Red algae (Trentepohlia) is common on rendered properties across Milton Keynes and produces a distinctive rusty-red discolouration. It grows faster on south-facing walls exposed to sunlight and rain. Many homeowners mistake it for iron staining or paint deterioration.
Biological growth on render retains moisture against the wall surface. Over time, this can lead to damp penetration — especially on older properties with single-skin walls or around areas where the render has cracked or deteriorated.
Pressure washing render — a common DIY mistake — can force water behind the render layer through cracks, expansion joints and around window openings. This causes internal damp that is expensive to remediate and may not become apparent for weeks.
A green or stained rendered property looks significantly less appealing than a clean one. For properties being sold, estate agents report that dirty render is one of the most common buyer objections during viewings — it suggests broader maintenance neglect.
Professional soft washing is the only safe, long-lasting solution for biological growth on render. It treats the cause, not just the symptoms — and protects your walls for months after treatment.
How It Works
Our 5-Step Process
Render Assessment
We inspect your rendered walls to identify the render type, the biological growth present, and any areas of damage or concern. You receive a fixed-price quote based on wall area and condition.
Surface Preparation
Heavy moss, cobwebs and loose debris are removed from the wall surface and around window frames before treatment begins.
Biocidal Treatment
Professional-grade biocidal cleaning solution is applied at low pressure across all affected walls. The solution kills algae, moss, lichen and mould at cellular level — including deep within the render pores.
Dwell and Rinse
After appropriate dwell time, the treated surfaces are gently rinsed at low pressure. Dead biological growth is flushed away, revealing the clean render underneath.
Post-Treatment Protection
A protective biocide coating is applied to inhibit regrowth. This treatment continues working for weeks after application, providing 6–18 months of protection depending on exposure.
Why Choose Us
The Benefits of Professional Render Cleaning (Soft Washing)
Safe for All Render Types
Our low-pressure soft wash method is safe for K-Rend, monocouche, silicone, acrylic, sand-and-cement and pebbledash finishes. No risk of surface damage or water penetration.
Kills Growth at Root Level
Unlike surface cleaning, our biocidal treatment penetrates render pores to kill biological spores at their source. This means dramatically longer-lasting results — not just a cosmetic clean.
Long-Lasting Protection
The biocide continues working for weeks after application, providing 6–18 months of protection against regrowth. Your walls stay cleaner for significantly longer than with any other method.
No Water Forced Behind Render
Low-pressure application means no risk of driving water behind the render layer — the most common cause of damp problems after DIY pressure washing.
Dramatic Transformation
Soft washing typically restores render to very close to its original colour. The visual difference between treated and untreated walls is immediately dramatic.
Increases Property Value
Clean rendered walls are one of the most visible improvements you can make to your property's exterior. The impact on kerb appeal is significant and immediate.
Expert Guide
Render Types, Growth Patterns and Treatment Science
K-Rend (silicone render) is the most common modern render system across new-build estates in Milton Keynes. It is designed to be breathable and water-repellent, but its textured surface provides ideal conditions for algae colonisation. The texture traps airborne spores and retains just enough moisture for them to establish. Once a colony forms in the render texture, rain and wind spread it across the wall surface. Our biocidal treatment penetrates the texture to kill spores within the render surface, not just on top of it.
Monocouche render (through-coloured render) is a single-coat system popular on modern housing developments. It comes in a range of colours and does not need painting. However, algae growth can partially mask the original colour, making it look faded or dirty. Cleaning restores the original colour without any need for repainting. We adjust our solution concentration based on the growth severity and the render colour — lighter colours may need slightly different treatment to avoid any temporary discolouration.
Traditional sand-and-cement render, found on older Milton Keynes properties and many extensions, is more porous than modern render systems. It absorbs moisture more readily and is more susceptible to biological growth. Our soft wash method is particularly important for this type — pressure washing can erode the surface and weaken the bond with the substrate. We use lower solution pressures and longer dwell times to compensate for the porosity.
Pebbledash render presents unique cleaning challenges. The textured stone surface provides deep crevices where biological growth can anchor firmly. Standard cleaning methods struggle to reach into these crevices. Our biocidal treatment is formulated to penetrate these recesses and kill growth that is physically inaccessible to brushing or rinsing alone.
The biological organisms we treat include green algae (the most common, responsible for the typical green discolouration), Trentepohlia (red algae that produces rusty-red or orange staining), black mould (common in damp, sheltered areas and around guttering), and lichen (crusty, circular growths that are extremely difficult to remove without chemical treatment). Each organism responds differently to treatment, and our solutions are formulated to target all common types.
Environmental factors determine how quickly render becomes colonised. North-facing walls receive less UV light (which naturally inhibits biological growth) and stay damper for longer. Walls shaded by trees, neighbouring buildings or boundary fences are also more susceptible. Properties near water features, streams or lakes experience higher ambient humidity. We take these factors into account when advising on treatment frequency and post-clean protection.
Common Questions
Frequently Asked Questions
Related Services
Areas We Serve
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