Written by Daniel Woodley. Fact checked by Hannah Miller. Published to Prices. Updated: 8th March 2023.

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Roof cleaning is an effective method of removing roof moss, lichen, dirt and other contaminants from roof tiles.

The result is a roof that looks fresh and clean.

For roofs with very old and weathered tiles, there’s the option of roof coatings – I’ve found that these coloured paints drastically improve the kerb appeal of the home and can act as a protective layer on the roof.

On this page I’ll cover:

  • A realistic price guide for roof cleaning and separately for roof coating.
  • Products that stop moss from growing on roof tiles.
  • What roof coatings do and can’t do (I dispel some myths and salesman’s claims)
  • Where you can get a quote.
  • Alternatives to roof cleaning.
  • + many more answers to common questions in our FAQs section.

Note: The price guide on this page is for roof cleaning with a power/pressure washer. To see our guide to roof moss removal, i.e. done with hand tools such as brushes and scrapers, check our guide to roof moss removal.

To understand how much it really costs to clean a roof, experts and consumer protection groups advise that customers should get at least 3 quotes and compare them.

I used to work in the roofing industry, but I changed career over 10 years ago, so I emailed photos and specifications of a roof to 34 cleaning and coating specialists and asked them how much they charge.

I requested two separate prices, one for roof cleaning and one for roof cleaning and coating.

Here’s a works schedule for a roof cleaning project, it’s based on the information provided to me:

  • Raise platform access towers to the roof edge (this provides roof edge protection for workers).
  • Protect the garden and surrounding areas with covers and tarpaulins.
  • Gain access to the roof via roof ladders.
  • Check for broken roof tiles and replace as needed.
  • Clean the roof tiles with a power washer.
  • Clear out gutters and clean exterior of gutters.
  • Clean the roofline fascias, soffits and bargeboards.
  • Check rainwater pipes to ground level and unblock as required.
  • Spray the roof tiles with a fungicide treatment to kill off any moss spores which will deter the moss from growing back.
  • Allow the roof to dry fully, and then apply two layers of coloured coating.
  • Lower the access platforms and take away all waste.
Roof tiles being coated with a colourant

1) Cost to Clean a Roof

This price guide is for roof cleaning only, it’s an average of the prices supplied to me:

Location:Price inc VAT:
London and South£900 - £1200
Midlands and North£750 - £1000

2) Cost to Clean and Coat a Roof

This price guide is for roof cleaning and then coating a roof with a coloured protective paint, again these are averages

Location:Price inc VAT:
London and South£2500 - £3000
Midlands and North£1750 - £2000

How to Stop Moss and Lichens Growing Back

The vast majority of roofs in the UK are covered in either clay or concrete tiles, and these have rough surfaces, which I’ve seen are conducive to the growth of moss, algae and lichens.

In fact, the “dirt” you see on roof tiles is really nothing more than organic growth, and once a roofer has removed it, one can stop it from coming back by applying a fungicide.

Whether you’ve had the moss from your roof removed manually with hand tools or with a power washer, the roofer should apply a fungicide to stop the moss from growing back.

I’ve seen roofs where the moss was washed off, but the roofers didn’t apply a fungicide, and I saw the moss come back within a year.

I’ve used Benzalkonium Chloride on roof tiles and many other hard surfaces, and I believe it’s the most powerful moss inhibitor.

What Happens if a Moss Inhibitor Isn’t Applied?

If any moss spores are left on the roof, they will start to grow as soon as they get wet and I’ve seen small sprouts of moss form in a matter of months, especially if it’s winter.

More widespread moss growth will form within a year, first on shaded parts of the roof, before migrating to all other areas.

I took the photo below and it shows moss growing between the tile overlaps where moisture lingers, and organic material, such as leaves, twigs and dust etc. collects.

This type of moss growth will appear regardless of whether the tiles have been coated with protective paint or not but I’ve found that its growth can be contained with periodical fungicide treatments.

Moss covered roof

I took this photo – note the moss isn’t growing on the tiles but in between the overlaps.

How to Permanently Prevent Moss From Growing Back?

While no one product or technique will stop moss from forming on roof tiles, I’ve found that this is the best approach:

  1. Get a roofer to demoss or clean the tiles.
  2. Get them to apply a strong fungicide.
  3. For roofs suffering from prolific moss growth, consider a roof coating that will smooth the tile surface, making it difficult for moss and lichen to grow.
  4. Get a roofer or cleaner to come back every few years and reapply the fungicide to stop moss from growing on the surface of the tiles and in the overlaps.
Roof treatment via a lance

The fungicide can be reapplied periodically to prevent the moss from growing back

Extra Costs to Consider

The prices I’ve published on this page are for a straightforward roof cleaning and coating project for a typical 3-bed home with an up-and-over roof.

Unfortunately, not every project is as easy as this, so use my guide as a starting point and consider these points:

Access Equipment – I’ve included the cost of access equipment in the form of tower platforms for edge protection and ridge ladders to access the roof. However, some roofs may require a full scaffold system which would cost extra. If your roof is three or more storeys high, has a large conservatory underneath it or is otherwise difficult to access, the moss removal project will cost more.

More Substantial Repairs – Before cleaning the roof, every contractor should first check for and then replace any broken roof tiles. More substantial repairs, such as replacing a roof valley, will need to be priced separately.

Roof Size – The prices on this page are for an “up and over” roof, that you would typically find above a three-bed home. Larger roofs, split-level roofs or those that are very steep will take longer to clear of moss and cost more.

Tile Type – Moss can be removed from any roofing tile, and most roofs in the UK are covered with concrete tiles, these are tough and difficult damage. Clay tiles are less popular but are more fragile, and specialist access equipment might be needed to access the roof without damaging them.

Key Benefits and Myths Debunked

I’ve found that the main benefit of roof tile coatings is aesthetic; there is no doubt that a recently painted roof will look fresher and cleaner than an old weathered one.

I know from my experience working in the roofing industry that roof tiles with a rough surface see less moss growth once coated with smooth paint, as this makes it difficult for moss and lichen to take hold.

Over the years, I’ve seen several myths perpetuated by eager sales staff and occasionally by outright fraudsters:

  • Coatings can increase house value – I have found no evidence that a freshly painted roof will increase the value of a home. In fact, many homeowners I’ve met like the look of a weathered roof, and you won’t find many homes in Country Life magazine that have had their roofs painted.
  • They increase the life of the roof – Most tiled roofs will last for many decades, and I’ve worked on roofs that were constructed over a hundred years ago and are still holding up well. Based on my experience, it’s extremely rare for a roof to need replacing due to failure of the roof tiles themselves; it’s usually due to the failure of the timbers that hold the tiles in place. Several firms have been prosecuted for making dubious claims about the benefits of roof coatings, and there were quite a few scams going around a few years ago.
  • Roof coatings can lower your heating bills – This was a claim I saw perpetrated by a few dozen firms that have now mostly disappeared. Several high-profile court cases brought by the UK’s Trading Standards have all but driven these firms out of business. The vast majority of tiled roofs in the UK are constructed over ventilated lofts. There is no thermal benefit to be had by painting tiles over a vented, cold loft. Insulation in most homes should be placed between the wall cavity or above the ceiling, not on top of the roof tiles.
  • Government grants and discounts – The government has never offered grants or subsidies for roof cleaning or coating despite fraudulent claims by some firms.

Get Your Custom Roof Cleaning Quotation Today

I hope you found these insights into roof cleaning and coating helpful.

As every project is different, the next step is to get a no-obligation custom quote for your roof:

  • Submit details of your roof cleaning or coating project.
  • Arrange a convenient time for a roof inspection.
  • Get your custom quote.
  • Compare prices.

Cleaning FAQs

When Were These Roof Cleaning Prices Published? Do They Include VAT?

I emailed photos and specifications to 34 businesses of various sizes and asked them to provide me with prices for roof cleaning and coating. Some were VAT registered and included this tax, while some smaller firms that were trading below the VAT threshold did not charge this tax.


Why Can't The Fungicide Be Used to Remove the Moss?

The fungicide I recommend will kill moss, lichens and other organic growth, and I’ve found it very effective, but it won’t physically remove it from the roof. It could take months, possibly years, for the dead matter to decay. Rainwater would almost certainly wash it into the guttering, rainwater pipes and possibly the drainage soakaways, where it would cause blockages.

I’ve always used fungicide as a surface biocide to clear the roof of moss spores once I’ve removed the bulk of the moss and other organic material.

Why Can't Roof Cleaning Be Done From Ladders?

The Health and Safety Executive’s rules for working at height are crystal clear; any worker who spends more than a few minutes on a roof must ensure there is adequate edge protection in place to prevent falls.

In most cases, this will mean a scaffold or a similar edge protection system must be in place at the edges of the roof to stop workers from falling.

HSE also state that group protection must take precedence over individual protection so scaffold or access towers should be used instead of or in combination with harnesses and ropes.

Read: No edge protection lands roofers in court.

I've Been Told That a Roof Coating or Sealant Will Prevent Future Leaks, Is This True?

The coating or sealant that is sprayed onto the roof tiles is as thin as a layer of paint and will not prevent leaks.

Can a Flat Roof Be Power Cleaned?

Extra care will be needed when working on a flat roof as they’re more fragile than concrete tiles. Moss shouldn’t be scraped or power washed off a flat roof but if the roof is in good condition, one may be able to brush the moss off.

I've Been Given a Quote That is Considerably Higher/Lower Than The Figures on This Page. What Gives?

Our prices are for a roof clean to a two-sided roof above a three-bed home, they are a rounded average of prices given to us by 32 roofing and roof cleaning firms.

If your price is significantly below this average, you may want to ask the roofer if they will be erecting edge protection. It’s not uncommon for roofers to complete this type of work from ladders even though they would be breaking the law. Some even walk on the roof with no protection whatsoever.

If the prices you’ve been given are much higher than our averaged price, it could be that you’ve sourced prices from a firm that has more overheads and needs to charge more. In general, the bigger the firm, the more they need to charge to make a profit.

We recommend sourcing at least three quotes from reputable roofers and comparing their work schedule and price to the information on this page.

Where Can I Find a Good Roofer?

The National Federation of Roofing Contractors and the Confederation of Roofing Contractors are well-known organisations that maintain databases of approved roofing contractors in the UK. The Competent Roofer scheme promotes roofers that agree to adhere to a high set of standards.

We’ve also partnered with Bark – one of the best places online for finding vetted, reviewed and rated tradespeople.

How Long Does it Take to Clean and Coat a Roof?

On the projects I’ve worked on or overseen, it’s always taken at least three days.

Here’s how the roofers I managed used to clean and coat the roof:

Day 1: First, we would erect the access equipment, inspect the roof, carry out repairs and then clean it. Next, we would apply a fungicide treatment.

We would then allow the roof to dry, which in the summer only took a few hours, but in the winter, it often took several days.

Day 2: On the second day, we would apply the coatings and in summer, we could sometimes get two coatings down in one day but usually, we would come back on day 3 to apply the second coat.

For larger or more complex projects, the work took longer.

Does Moss Damage Roof Tiles?

The vast majority of roofs in the UK are covered with concrete tiles, and for the most part, I’ve found that they are strong enough to prevent any damage from moss growth.

In extreme circumstances, for example, when the roof is carpeted in moss, it may eat away at the surface, which essentially accelerates the weathering process, but this is very rare and not something I’ve ever seen lead to damage.

On more fragile clay tiles, the extra moisture held by the moss can lead to an increased risk of damage in winter due to the freeze/thaw process. This is something I’ve seen several times, mossy roofs stay damp and when the moisture freezes, it cracks the tiles.

While wet moss is heavy, the weight never threatens the structural integrity of the roof as it’s spread thinly. Roofs in the UK are designed to withstand wind pressures and the weight of several feet of snow, I’ve seen moss cause any form of structural damage to a roof.

What is the Best Way to Remove Roof Moss?

If your goal is to remove the roof moss and stop it from returning, then either manual roof moss removal or power washing techniques will suffice.

However, if you need the roof to be cleaned rather than just demossed, perhaps because you want to apply a roof sealant or coating, then it should be power washed. Before a sealant or coating can be applied to a roof, the surface must be thoroughly cleaned of all contaminants, including algae, dirt, grease and pollution.

What Are The White and Yellow Marks on Roof Tiles?

White and yellow marks on roof tiles are lichen, a slow-growing thin organism that’s very tough to remove.

I’ve found that the best way to remove it is by power washing or by treatment with a fungicide.

The fungicide requires time to work but 4-6 weeks after the application, most of the lichen should’ve disappeared.

I do not recommend trying to remove lichen with scrapers or wire brushes as I’ve seen this method scratch and scuff the tiles.

About This Price Guide | Our Experience

Daniel Woodley created this guide to the cost of roof cleaning and coating.

Daniel spent 10 years working in the roofing industry before spending 8 years as a project manager for a construction and landscaping firm. He currently works as a landscaping consultant and created this website to help others achieve the garden of their dreams.

Daniel publishes price guides on this website so readers can understand how much home improvement and gardening projects cost. He only writes about projects he has experience with, which are mostly roofing, home improvement and gardening related.

Author: Daniel Woodley

Daniel has over 18 years of experience in the construction, home improvement, and landscape garden industries, including a spell working as a project manager.

In his spare time, Daniel enjoys gardening, hiking and scrambling. He frequently posts videos to his popular YouTube Channel and is well known in the hiking community.

More About Daniel Woodley.

Daniel Woodley

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