Written by Muhammad Ahmad, Construction Superintendent at Golden Roofing Expert Ltd. Last updated: 26 October 2026.
When London homeowners ask us about roof cleaning, it is nearly always about moss, not dirt. Moss holds water against tiles, lifts the edges of slates, drops into gutters and makes a roof look decades older than it is. We remove it by hand, treat the roof so it does not come straight back, and check the covering while we are up there.
Over 15 years on London roofs, I have seen what happens when the job is done badly. The commonest case is a roof that has been jet-washed, where the moss is gone and the tiles are left rough, with ridge mortar loosened and water running down into the loft the next time it rains. This guide explains how we avoid that, what it costs, and when a roof clean is not the right answer.
In short:
- We scrape moss by hand and apply a biocide at low pressure. We do not use high-pressure jets.
- Gutter and downpipe clearing is done in the same visit.
- You get before and after photographs and a written note of anything that needs repair.
- Surveys and quotes are free.
Why Moss Grows So Fast on London Roofs
London roofs are good places for moss. Terraces are often overshadowed by neighbouring buildings and street trees. Winters are damp and mild, and old porous concrete tiles hold water long after rain stops.
The roofs we treat most often share these features:
- North-facing slopes that rarely dry
- Roofs under trees, where leaf litter keeps the surface wet
- Older concrete tiles, whose surface has weathered and become rough
- Low-pitched sections where water drains slowly
Moss is not just cosmetic. It acts like a sponge, and in a cold snap the trapped water freezes, expands and breaks down the tile surface. Moss also grows in tile joints and on ridge mortar. When it falls away, it ends up in your gutters. If you have already seen damp patches inside, read our guide to the signs of a leaking roof.
What Our Roof Cleaning Service Includes
- Manual removal of moss, lichen and algae
- Low-pressure biocide treatment to slow regrowth
- Gutter and downpipe clearing
- A check of tiles, slates, ridges, flashing and valleys
- Photographs before and after
- A written note of recommended repairs, quoted separately
We never carry out extra work without your agreement.
Why We Don’t Pressure Wash Roofs
Pressure washing looks impressive for a few weeks. The problems show up later.
- It damages the tile surface. Tile manufacturers do not recommend it. Wienerberger’s roof tile cleaning advice warns that the jet can damage the tile finish and strip colour from concrete tiles.
- It forces water under the tiles. Spray directed upwards can push water past the laps and onto the felt.
- It loosens ridge and verge mortar. We have been called out to re-bed ridges within days of a pressure wash by another firm.
- It can affect your guarantee. Check the manufacturer’s terms before anyone uses a jet on your roof.
Some contractors offer “soft washing”, which uses a low-pressure rinse and biocide. It can be done safely. But on a roof I have inspected, the best result has always come from taking the bulk of the moss off by hand first, then treating what is left. A biocide on thick moss only turns it brown.
How We Clean a Roof, Step by Step
- Survey and photographs. We check the roof type, pitch, access and condition before we start.
- Hand removal. We scrape and brush the moss off, working from the ridge downwards so we never lift the tile edges.
- Gutters and downpipes. A clean roof draining into a blocked gutter only moves the damp to your wall, so we clear them the same day.
- Biocide treatment. We apply a fungicidal wash at low pressure to kill the spores left behind. Biocides are regulated in the UK, and the HSE explains the rules on biocidal products. We keep run-off away from plants, ponds and neighbours’ property.
- Inspection. We look for slipped tiles, failed flashing and crumbling mortar while we are there.
- Report. You get the after photographs and a plain note of what needs attention.
Treated moss does not vanish at once. It dies back and washes away over the following weeks. We tell every customer to expect this, because the roof looks only partly better on the day.
How Much Does Roof Cleaning Cost in London?
Price depends on roof size, pitch, access and how heavy the moss is. A typical terraced house is priced from £450 to £1,200, including gutter clearing and treatment. Larger roofs, steep pitches and heavy moss sit at the top of that range, and we confirm the price in writing after the survey.
Factors that push the price up:
| Factor | Effect on cost |
|---|---|
| Steep pitch or several roof levels | More time and safety equipment |
| Heavy, thick moss | Longer hand removal |
| Difficult access, or scaffolding needed | Access priced separately, and we tell you before booking |
| Repairs found during the clean | Quoted separately, never added without your say |
The only reliable way to price a roof is to see it. Send us a photo or request a survey and you will get a written quote with no obligation.
When Roof Cleaning Is Not the Right Answer
A good roofer sometimes advises against a clean. These are the cases where I would not recommend it:
- The tiles are worn through. Cleaning removes moss that may be holding a crumbling surface together. On badly worn roofs, repair or replacement is the honest advice.
- Widespread slipped or cracked tiles. Walking on them risks more breakage, so repair first.
- Failed flashing or valleys. The roof needs repair, not cleaning. See our roof repair in London service.
- Roofs near the end of their life. Cleaning only delays the problem. We will say so and explain whether a new roof installation makes more sense.
To catch problems early, our roof maintenance service combines inspection with cleaning. Our guttering and soffits and fascias teams cover the roof edge, which cleaning alone cannot fix.
Safety Checks Before Any Roof Clean
We check several things before we scrape a single tile:
- Asbestos cement. Some older garages and outbuildings have asbestos cement sheets. These must never be scraped or brushed. If we suspect it, we stop and advise you.
- Wildlife. Birds nest in roofs in spring, and bats and their roosts are legally protected. The Bat Conservation Trust explains the law. If we see signs of either, we pause and advise you.
- Fragile surfaces. Some rooflights and older materials will not take a person’s weight, so we use the right access equipment.
- Working at height. The HSE publishes guidance on safe working on roofs. Tiles are not designed to be walked on, which is why we do not recommend homeowners climb up themselves.
Roof Cleaning Across London
We carry out roof cleaning in Camden, Islington, Hampstead, Highgate, Barnet, Brent, Kilburn, Willesden, Wembley, Harrow, Ealing, Hammersmith, Chiswick, Westminster, Kensington, Chelsea, Hackney, Tower Hamlets, Stratford, Lambeth, Southwark, Lewisham, Greenwich and Wandsworth. Shaded terraces in Camden, Islington, Hampstead, Ealing and Brent are the roofs we treat most often. If your postcode is not listed, call and we will confirm cover.
Why Use a Roofer for Roof Cleaning?
A cleaner can make a roof look better. A roofer can tell you whether it is sound. We work at height every day, carry the right access equipment, and can repair what the clean exposes, so there is one visit, one quote and one company.
- 5.0 rating from 489 Google reviews, and listed on TrustATrader
- Local base at 10 Sale Pl, Tyburnia, London W2 1PX
- Written quotes and no doorstep pressure
You can read more on our about page, and for standards that apply to roofing contractors see the NFRC. If the clean turns up damaged tiles or a failing chimney, we can quote for tiled and slate roof repair, chimney repairs or a full roof repair at the same visit.
Roof Cleaning London FAQs
How often should a roof be cleaned in London?
Every three to five years for most homes. Shaded roofs under trees may need it sooner.
Is hand removal safe for my tiles?
Yes, when done by someone who works on roofs. We scrape downwards and avoid heavy pressure on concrete, clay and slate.
Will cleaning stop the moss coming back?
It slows regrowth significantly, but no treatment stops moss permanently in a damp climate.
What is the best time of year to clean a roof?
Dry spells in spring and early autumn usually work well. We will advise on timing when we survey.
Do you clear the gutters as well?
Yes. Gutter and downpipe clearing is included.
How long does a roof clean take?
Most terraced and semi-detached houses take a few hours to a day, depending on size and moss growth.
Can I clean my own roof?
We advise against it. Falls from roofs cause serious injuries, and it is easy to crack tiles by walking on them.
Book Roof Cleaning in London
Call +44 7723 782655, email info@goldenroofing.co.uk, or request a free quote. Send a photo of the roof if you can, and we will tell you what is involved.