Your render’s gone green on the shady side again. Welcome to RH1 — the damp valley floor where algae thinks it lives rent-free. We soft wash it off and kill it at the root, so it stays gone. Patrick’s based here, so we’re usually same day or next.
Four steps. The biocide does the cleaning, not the pressure — that’s what makes it stick on damp RH1 walls.
Protect
Plants and lawn wetted down first, delicate borders sheeted. Half of Redhill’s semis have a hedge right up against the gable — that gets covered.
Apply biocide
Low-pressure soft-wash solution onto the render or tile. It soaks into the texture and the lichen pits where a jet would just skim over the top.
Dwell
15–30 minutes to kill the algae at root level. This is the bit that beats the RH1 humidity — spores die instead of bouncing back in eight weeks.
Rinse
Low-pressure rinse from the top down. Garden hosed off after, full clear-up, and we walk it with you. Not right? We redo it free.
By Patrick, Same Day Jetwash — Redhill (RH1) exterior cleaning. Last updated: June 2026.
The short answer: soft washing is a low-pressure (typically under ~100 psi)[1] cleaning method that uses a specialist biocide — not mechanical force — to kill algae, lichen and moss at root level on render, roofs and cladding. In Redhill (RH1), where the damp Vale of Holmesdale valley floor keeps humidity high, that root-level kill is what stops the green coming straight back. We charge from £5/m² for render and £15–£30/m² for roof tiles, and call back within 2 hours.
Before & after
Illustrative example of typical soft washing results in Redhill — representative, not a specific customer job.
Why Redhill render goes green faster than the next town over
Here’s the honest version. Redhill sits on the floor of the Vale of Holmesdale — the low corridor between the North Downs chalk and the Greensand ridge. The bedrock here is Lower Greensand on the valley floor with Weald Clay edges towards Salfords and South Nutfield[3], and it holds damp. Add the valley humidity that hangs about over Earlswood and the Mole tributaries and you’ve got the perfect conditions for algae. It’s not your house. It’s the postcode.
The bit nobody tells you: it always starts on the north and shaded elevations. South-facing walls bake dry in the afternoon and stay greener for longer between cleans. North gables and anything under a tree never properly dry out, so the green takes hold there first and worst.
And the housing stock makes it worse. RH1 is full of 1930s–60s rendered semis, a lot of them around Redstone Hill and central Redhill, plus pebbledash everywhere. That textured render is a thousand tiny ledges for spores to sit in. A pressure washer skates straight over the top of it and leaves the roots behind — which is exactly why it’s back by spring. Soft wash is the fix: low pressure, specialist biocide, root-level kill. Soft washing applies a sodium-hypochlorite-based biocide at low pressure (typically under ~100 psi) so the chemistry does the work rather than the jet[1] — that’s what kills the algae and lichen at the root instead of just blasting the surface growth off.
Low-pressure application on render — the biocide soaks into the texture, no high-pressure damage.
What we soft wash on Redhill homes
Rendered semis & detached — K-Rend, silicone, acrylic and old-school painted render on the RH1 1930s–60s stock. Manufacturer-recommended method on modern render.
Pebbledash — classic Redhill finish, and the texture is exactly where lichen loves to live. Biocide gets into the dimples.
Roof tiles & slate — always soft wash, never pressure. High-pressure washing can strip the protective surface off concrete and clay tiles, which is why tile-cleaning guidance recommends low pressure (no more than ~4–5 bar / 60–70 psi) instead.[2] Mossy RH1 detached pitches are bread-and-butter for us.
UPVC & timber cladding — common on newer Earlswood and Salfords builds. Pressure marks UPVC and raises the grain on timber; soft wash doesn’t.
Brick & natural stone — for the green organic staining, not the brick itself. Won’t etch the face.
Honest Redhill prices
No “£60 for any house” nonsense — that maths doesn’t work and you’ll be calling someone else to redo it in a year. These are the same rates as our main soft washing page, just so you know what an RH1 job actually costs:
Surface (typical RH1 home)
Soft-wash price
How long it lasts
Render / cladding
£5–£8/m²
2–4 years
Brick / natural stone
£6–£10/m²
2–4 years
Roof tiles / slate
£15–£30/m²
Years (biocide between cleans)
Difficult access (gables, scaffolds)
£10–£12/m²
2–4 years
Typical RH1 house front
£200–£500
2–4 years
Whole property exterior
£400–£1,200
2–4 years
Final price depends on size, condition and access — a north gable behind a hedge takes longer than a clear south wall. Most RH1 jobs are quotable from a photo. Want a rough number now? Try the cost calculator.
Why a same-day local crew matters here
Redhill’s our home patch. Patrick is based in RH1, so most weeks we’re same-day or next-day for Redhill, Merstham, Salfords, Earlswood and Nutfield — you’re not waiting two weeks for someone to drive in from out of county. And because we actually live with this geology, we know to start on the north elevation, we know pebbledash needs the dwell time, and we know which Earlswood and Salfords streets sit near surface-water drains where the rinse needs capturing properly. That local read is the difference between a job that lasts four years and one that’s green again by spring.
Where we cover in RH1
All of Redhill plus the surrounding RH1 villages — Redhill town, Merstham, Salfords, Earlswood, Nutfield and South Nutfield. Reigate (RH2) is next door, Horley (RH6) to the south, and we cover the rest of Surrey within 20 miles of RH1. Call 01737 652 515 and Patrick will talk through your render in five minutes.
Redhill bedrock geology (Vale of Holmesdale: Lower Greensand valley floor between the North Downs chalk and the Greensand Ridge, Weald Clay to the south) — British Geological Survey Geology Viewer, bgs.ac.uk.
Redhill soft washing FAQs
Most-asked questions from RH1 homeowners.
How much does soft washing cost in Redhill?
£5–£12 per m² depending on surface and access. A typical RH1 rendered house front is £200–£500, a whole property £400–£1,200, and roof tiles £15–£30/m². Free quote, no obligation — most Redhill jobs are quotable from a photo and your postcode.
Why does the render on my Redhill house keep going green?
Redhill sits on the damp floor of the Vale of Holmesdale, so humidity stays high and shaded north elevations dry slowly — perfect for algae, especially on the textured 1930s–60s rendered semis around Redstone Hill. Pressure washing knocks the green off but it grows straight back. A soft-wash biocide kills it at the root so it stays clean for 2–4 years.
Do you cover Merstham, Salfords and Earlswood?
Yes — every postcode in RH1 including Merstham, Salfords, Earlswood, Nutfield and South Nutfield. Redhill is our home patch, so we’re usually same-day or next-day. We also cover Reigate (RH2), Horley (RH6) and the rest of Surrey within 20 miles of RH1.
Can you soft wash a roof in Redhill?
Yes — and on a roof it’s the only sensible method. Pressure strips the factory coating off concrete and clay tiles. We soft wash with a biocide that clears moss and lichen without damaging the tiles. Roof tiles run £15–£30/m² in RH1 depending on pitch and access.
