How to keep render clean: maintenance and aftercare guide
Updated 6 November 2026 · By the Render Cleaning team
How often render needs cleaning
| Wall situation | Typical cleaning interval |
|---|---|
| Open, sunny, south-facing | Often five years or more |
| East or west-facing | Around three to five years |
| North-facing | Around two to four years |
| Shaded by trees or hedges | Every one to three years |
| Rural or coastal, high exposure | Every one to three years |
These are rough guides. A protective treatment after cleaning can extend the interval, and catching growth early makes each clean quicker and cheaper.
Fix the causes of growth
- Repair leaking gutters, joints and downpipes that soak the wall
- Clear gutters so they do not overflow in heavy rain
- Check sills and copings have drips that throw water clear of the render
- Cut back trees, climbers and shrubs touching or overhanging the wall
- Redirect overflow pipes that run down the render
- Make sure soil and planters are not piled against the bottom of the render
Best time of year to clean render
Spring to early autumn is usually the best window, when temperatures are high enough for biocides to work and drier spells give the product time on the wall. Cleaning in spring removes winter growth before it spreads through the summer. Autumn cleaning, followed by a protective treatment, helps walls go into the damp winter months clean. Freezing weather and prolonged rain are best avoided.
If you are selling, aim to have the render cleaned a few weeks before photos are taken, so any slow-fading staining has time to clear. Booking early in spring also helps, as many render cleaners get busy from late spring onwards.
Light maintenance cleans
A maintenance clean is a lighter, quicker version of the full job, done before growth becomes heavy. Because there is less to kill and rinse away, it usually takes less time and costs less than leaving the walls until they are badly green. It is particularly useful on the one or two walls that always go first.
| Approach | What it involves | When it suits |
|---|---|---|
| Full clean | Biocide, dwell, thorough rinse of all walls | Heavy growth or first clean |
| Maintenance clean | Lighter biocide application on affected walls | Early signs of growth returning |
| Protective re-treatment | Residual biocide or repellent on clean walls | Shaded walls that green up quickly |
Catching the first light green haze, rather than waiting for thick growth and black streaks, keeps the render looking consistent and reduces the amount of product used on the wall over its life.
What not to do
- Do not pressure wash render, even on a low setting, without knowing the render type
- Do not scrub silicone or monocouche with stiff brushes
- Do not use undiluted household bleach on coloured render
- Do not paint through-coloured or silicone render with ordinary masonry paint without checking compatibility
- Do not let climbing plants attach to render, as they hold moisture and can damage the surface
Simple yearly checklist
- Walk round the house in spring and autumn and look for new green or black patches
- Check gutters and downpipes after autumn leaf fall
- Look for new cracks, especially around windows and corners
- Tap any areas that look raised to check for hollow render
- Check sealant around windows and doors where it meets the render
- Note which walls green up first, so they can be cleaned or treated early
Small cracks and failed sealant are worth fixing promptly. Water getting behind render through gaps around windows, pipes and fixings is a far bigger risk to the wall than surface algae, and on thin-coat systems over insulation it can lead to costly repairs. Any new fixings, such as satellite dishes, cameras or lights, should be sealed properly where they pass through the render.
Keep a simple record with the date of each clean, the products used and photos of each wall. Over a few years it shows clearly which walls need attention most often, and lets you plan maintenance cleans for those walls only rather than the whole house.
Maintenance for landlords and managing agents
Green and streaked render makes a property look neglected, which matters when letting, selling or managing a development. A planned cleaning cycle, with shaded elevations done more often, is usually cheaper than waiting until growth is heavy across every wall. Recording the render type, any manufacturer guidance and the date of each clean and treatment makes it easier to plan future work and to show the render has been maintained.
On blocks and estates, cleaning whole elevations at the same time keeps the colour consistent, as a single cleaned wall next to an uncleaned one can look patchy. For taller buildings, combining render cleaning with other work that needs the same access, such as gutter clearing, window cleaning or sealant replacement, can make better use of the cost of towers or powered access.
Related guides
- How much does render cleaning cost in the UK? (2026 guide)
- Why is my render going green? Causes and how to fix it
- Can you pressure wash render? Safer ways to clean it
- How to choose a render cleaning company: questions to ask and red flags
- What type of render do I have? How to identify it before cleaning
- Clean, repaint or re-render? Choosing the right fix for tired render
- Render cleaning: how long it takes and what to expect on the day
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