Modern rendered houses look stunning when new — and streaky, patchy and tired within a few years. Red and green algae colonise K-rend and silicone render relentlessly in the North West damp, creeping across the walls in tide marks that no amount of rain washes away.
We soft wash rendered properties across Greater Manchester — Manchester, Stockport, Salford, Altrincham, Sale, Denton, Bury and beyond. Soft washing uses low pressure and specialist treatments rather than a forceful jet, so the algae dies and rinses away without damaging the render finish.
What is render & soft washing?
Render soft washing is a low-pressure cleaning method for rendered walls — K-rend, silicone render and similar modern finishes — that kills algae, lichen and general grime with specialist treatments instead of blasting it off with high pressure. The render is pre-treated, left to dwell, then rinsed gently: the chemistry does the work the pressure cannot safely do.
This matters because render is a coating, not a solid surface. A high-pressure jet can pit it, strip its colour and force water behind it, causing far more expensive damage than the algae ever would. Soft washing is the method render manufacturers recommend, and it is the only way we clean it.
How we do it
- Inspect the render: We check the type of render, look for cracks, hollow or blown areas and failed sealant around windows, and note how far the algae has spread. Anything structurally wrong — cracked or detached render — gets flagged, because cleaning will not fix it and pressure near it is avoided entirely.
- Protect windows, plants and paintwork: Windows and doors are pre-wetted, delicate planting below the walls is covered or soaked, and nearby painted surfaces are masked where needed. The treatments are render-safe, but we take no chances with your garden or your glazing.
- Apply the soft-wash treatment: A specialist algae treatment is applied across the render at low pressure, working from the bottom up to avoid streaking. It is left to dwell — typically 20 to 40 minutes — so it can kill the algae right down to the root rather than just bleaching the surface.
- Gentle rinse: The walls are rinsed with low-pressure water, washing away the dead algae and treatment residue. Stubborn patches may get a second light application rather than a harder rinse — patience protects the render.
- Final check: We walk the property with you, checking the walls are evenly clean and the windows and garden are untouched. Any cracks or blown render we spotted are pointed out so you can get them repaired before water gets in.
Why have it done
- Removes red and green algae without damaging the render
- Low-pressure method safe for K-rend and silicone finishes
- Treatments kill algae at the root for longer-lasting results
- Windows, plants and paintwork protected during the clean
- Restores the even, like-new colour of the walls
Red and green algae: why render goes streaky
The red and green staining on render is living algae, feeding on the damp North West air. It starts in the spots that stay wet longest — under sills, around downpipes, on north-facing walls — and spreads in tide marks that follow every rain run. Once established, rain alone will never shift it.
Bleach-based DIY attempts usually just lighten the surface while the roots survive underneath, so the staining is back within months. A proper soft-wash treatment kills the organism fully, which is why the result lasts years rather than weeks.
What soft washing will not do
Honesty matters here: soft washing removes biological growth and grime, but it will not fix cracked, blown or hollow render, and it will not recolour render that has faded unevenly in the sun. If the render itself is failing, it needs a renderer, not a cleaner — and we will tell you which it is before we quote.
What it does brilliantly is return sound render to an even, clean finish and keep it that way. If your brickwork needs attention rather than your render, our brick and exterior wall cleaning covers that side of the house.
What does it cost?
As a rough guide, render soft washing across Greater Manchester typically falls between £200 and £450 depending on the size of the property, how many walls are affected and how heavy the algae growth is — every job is quoted free after a look at photos or a quick site visit.
Render & Soft Washing FAQs
How much does render cleaning cost in Manchester?
Most rendered homes across Greater Manchester fall between £200 and £450. The number of affected walls and the overall size of the property matter most, then how heavy the algae is — light staining is quick work, walls black with growth need longer dwell times and repeat applications. Photos or a visit get you an exact free quote.
Will soft washing damage my K-rend or silicone render?
No — soft washing is specifically the safe method for render. We use low pressure and specialist treatments rather than a forceful jet, which is what damages render by pitting the surface, stripping colour or forcing water behind the coating. We also inspect for cracked or blown render first and avoid pressuring those areas entirely.
Will the red and green staining come back?
Eventually, yes — render in the North West will always recolonise in time, because the damp air suits algae. But a proper soft-wash treatment kills the growth at the root, so you are looking at years before it becomes noticeable again, not months. North-facing walls and areas under leaking gutters will always go first.
How do you protect my windows and garden?
Windows and doors are pre-wetted before treatment goes on, delicate planting is covered or thoroughly soaked so any run-off is diluted, and nearby painted surfaces are masked where needed. The treatments are chosen to be render-effective but garden-safe with these precautions, and we rinse everything down afterwards.
My render is cracked in places — can you still clean it?
We can clean the sound areas, but we will avoid pressuring cracked or hollow render and we will tell you about it plainly. Cleaning does not fix failed render — that needs a renderer to repair first, otherwise water gets behind the coating. We would rather flag it during the quote than clean over a problem and leave you with a bigger one.
How do I clean rendered walls myself?
Apply a render-safe algae cleaner with a garden sprayer, working from the bottom up to avoid streaking, leave it to dwell for 20 to 40 minutes, then rinse gently with a hose or a pressure washer on its lowest setting held well back. Never use bleach, which can discolour render, and never use a high-pressure jet, which pits the surface and forces water behind the coating. This handles light algae; heavy staining or large areas are honestly better left to a professional soft wash.
How long does render soft washing take?
A typical semi-detached house takes half a day to a full day, depending on how many walls are affected and how heavy the algae is. The treatment dwell time — 20 to 40 minutes per section — sets the pace, and stubborn areas may need a second application. Detached houses with all four elevations affected can take a full day. We tell you the expected time in the quote, and the walls are left to dry naturally afterwards.
How often should render be cleaned?
Every three to five years suits most rendered homes in Greater Manchester, because a proper soft wash kills the algae at the root. North-facing walls and areas under dripping gutters will go first — fixing the gutter extends the clean noticeably. If the staining is returning within a year or two, something is keeping the wall wet — usually a leak, failed sealant or poor drainage — and that is worth investigating before another clean.
Can you get white render back to white?
Usually, yes — dramatically so. White and light-coloured render shows algae worst, which is why the transformation on a white rendered house is often the most striking work we do. The red and green staining lifts with the soft-wash treatment and the original colour comes back evenly. The honest caveat is sun-faded or patch-repaired render: cleaning removes the growth, but it cannot even out colour differences in the render itself.
Is soft washing safe around children and pets?
Yes, with sensible precautions. We ask that children and pets stay indoors while the treatment is being applied and during the dwell time, then the walls are rinsed thoroughly and the area is safe once dry. The treatments are chosen to be effective on algae but to break down with rinsing, and we soak down any nearby planting. If you have a pond, tell us before we quote — we will take extra care around it.
Render & Soft Washing across Greater Manchester
We're mobile and cover the whole region. Pick your area: