Render & Pebbledash Cleaning
Deceptively fragile. Render greens up faster than anything else in the North West climate — and a pressure lance held too close will take the top coat off and leave a patch worse than the dirt.
Render is the surface where we're most often called in after somebody else has had a go. It looks solid and it looks washable, so the instinct is to point a pressure washer at it — and the result is a wall with clean stripes where the lance passed, blown patches where it lingered, and a finish that now needs a decorator rather than a cleaner.
It's also the surface most affected by the North West climate. Render holds moisture at the surface, and a damp, shaded, west-facing wall in Greater Manchester is close to ideal for algae. Plenty of the render we clean isn't dirty in any meaningful sense — it's green, and it's green because of where it is.
Why render goes green so fast
Algae needs three things: moisture, light and a surface to sit on. Render provides an excellent surface — slightly textured, mildly alkaline when new, and able to hold surface water long enough for growth to establish. The North West supplies the rest generously.
It's rarely evenly distributed, and where it appears tells you a lot. Growth concentrated below a window usually means a failed sill or a missing drip. A green stripe down one section normally traces a leaking gutter joint or a blocked hopper. Growth up from the ground is splashback, often where a path or drive sits too high against the wall. Heavy growth on one whole elevation is usually just aspect — north or west facing, shaded by a tree or a neighbouring building.
Cleaning fixes what you can see. If there's a defect feeding it, the growth returns quickly and in the same pattern. We photograph and flag anything obvious, because a five-minute gutter repair frequently saves the next three cleans.
If your render is green in one specific vertical band, look up before you book a clean. There's very often a gutter joint or a hopper directly above it, and fixing that is cheaper than cleaning it every year.
How we clean render safely
Almost always with low-pressure superheated steam, and often with nothing else. The heat kills the algae and its spores in the surface, and the low pressure means the render is cleaned rather than eroded. Water volumes are low, which matters on a wall with any cracking, because you don't want to be pushing water into the structure behind it.
For heavier or long-established growth we'll follow the clean with a biocide wash — left on the surface rather than rinsed, so it keeps working. That's the step that determines whether the wall stays clean for one season or several, and it costs very little on top of a clean that's already happening.
- Survey the render — type, condition, cracking, coatings, and what's feeding the growth
- Low-pressure steam across the full elevation, never a spot clean
- Biocide finish to kill spores in the surface and slow regrowth
- Flag defects — blown patches, cracks, gutter and sill problems — with photos
Why we clean whole elevations
Render weathers as a single continuous plane, with no joints, bays or texture changes to break up the eye. That makes patch cleaning look far worse on render than on brick or stone: a clean square in the middle of a weathered wall is glaringly obvious, and it doesn't blend over time — it just weathers back to matching in a couple of years while looking wrong throughout.
So we quote by elevation rather than by area. If there's a tag in the middle of a gable, the honest quote is for the gable, not for the square metre around the tag. It's occasionally a more expensive conversation at quote stage, but it avoids handing back a wall that looks patched.
Green render or a tag on a rendered wall?
We clean render across Greater Manchester and Cheshire without the lance marks. Send a photo and we'll quote the elevation properly.
Graffiti on render
This is a genuinely difficult combination, and it's worth being realistic. Render is porous and usually painted or coloured through, so you're trying to remove one coating from another without touching the one underneath.
Sometimes it works cleanly — a fresh tag on sound, modern painted render often lifts with a mild gel remover and steam, and we'll prove it on a test patch first. Often it doesn't: the remover softens the render's own coating, or the pigment has soaked into an unsealed surface, and the realistic outcome is that the elevation needs repainting.
We'll tell you which it is after a test patch rather than after the whole wall. Where a rendered elevation is a repeat target, an anti-graffiti coating is the sensible investment — it's much cheaper than repainting a gable annually, and it has to be a breathable system so the wall can still dry out.
External wall insulation
A lot of render across the region's social housing stock isn't render on masonry — it's a thin coat over external wall insulation, applied during retrofit programmes. It looks identical from the ground and behaves completely differently.
EWI render is thin, applied over a soft insulation board, and there's no structural masonry immediately behind it. It's easily damaged by pressure, and any water that gets through a crack has nowhere useful to go. If a building has been through an EWI programme it's worth telling us, because it changes our approach and we'd rather know at survey than find out with a lance in hand.
Render At A Glance
Where we come across it
- Housing association and council stock across Salford, Oldham and Rochdale
- Post-war semis and estate housing throughout Greater Manchester
- Modern K-Rend and monocouche on new-build residential and commercial
- External wall insulation systems retrofitted to solid-wall properties
What damages it
The mistakes we're most often called in to fix.
- High pressure blows the top coat off and leaves permanent lance scarring
- Patch cleaning shows badly — render weathers as a single visible plane
- Cracked or blown render lets cleaning water into the wall behind it
- Strong chemicals can bleach coloured through-render unevenly
What We Remove From It
Methods We Use On It
Frequently Asked Questions
Can you pressure wash render?
You can, and it's how most render gets damaged. High pressure blows the top coat off, leaves lance scarring that doesn't weather out, and drives water into any cracks. We clean render with low-pressure superheated steam instead, which removes the growth and grime without touching the surface itself.
Why does my render keep going green?
Because something is keeping it damp. Aspect is part of it — north and west-facing walls in the North West stay wet — but a distinct pattern usually points to a defect: a leaking gutter joint, a blocked hopper, a failed sill or splashback from ground level. Cleaning with a biocide finish buys years rather than months, but fixing the water source is what actually solves it.
Will you clean just the patch where the graffiti is?
We'd advise against it on render. With no joints or texture to break up the surface, a cleaned patch reads as obviously as the graffiti did and takes years to blend. We normally quote by elevation so you get a wall that looks right, and we'll explain that at quote stage rather than surprising you with it.
Is cleaning safe on external wall insulation?
Yes, with the right method — low-pressure steam is fine. Pressure washing is not: EWI render is thin, sits on soft insulation board rather than masonry, and damages easily. Please tell us if a property has had EWI fitted, as it isn't always obvious from the ground and it changes how we work.
Areas We Cover
We clean render across Manchester, Greater Manchester and Cheshire, including:
Other Surfaces We Clean
Need graffiti gone — fast?
Call 0161 399 5247 or request a free quote. We respond within one working hour.