How Much To Pressure Wash Roof

Have you looked at your roof lately? If so, it probably wasn't a pretty sight, and now you're wondering, "How much moss can grow in one place??"

As well as all that moss, there's going to be lichen, algae, various fungi, dead leaves, bird droppings, and a whole load of other accumulated muck.

No, it doesn't look great, and it can be bad news - and we'll elaborate on this later.

One extremely effective way to shift all of this dirt and filth is to blast it off using a pressure washer. The question is, do you hire or buy one and do it yourself, or do you look up professional roof cleaners to do the job for you?

The Tripleclean Gang strongly recommends that you do the latter, for several good reasons that we'll spell out in a moment. But then we come to the most important question: how much does roof cleaning cost?

In this blog, we'll explore this question and throw in some useful pointers along with advice to help you to reach your own conclusions as to the best course of action.

Roof Cleaning Costs

When you are researching the possibility of having your roof pressure washed, it's only fair to ask what you're getting for your money - it's only natural to want to know what all your hard-earned cash is being spent on.

As you probably guessed, the main factor affecting the cost of roof cleaning is the size of the roof space. It goes without saying that a large roof will generally cost more to clean than a small roof space.

However, there are other issues that will affect the roof cleaning prices, such as:

How Much To Pressure Wash Roof

Your Location

Anyone living in London and the southeast will be painfully aware that the cost of living is much higher there. Recent figures suggest that those living in London itself can expect to pay up to 58% more for goods and services than in other urban areas.

In general, roof cleaning costs will become gradually lower the further north you are located.

The Roof Cleaning Method

Although we are concentrating on pressure washing here, it's only one of the cleaning methods available. There are a few different ways to clean a roof, and professional roof cleaning companies usually offer a range of options, like Soft Washing, moss removal, steam cleaning, or biocide treatment. The prices for these will vary according to the effort involved, the complexity of the task, and the equipment used. Also, these companies will often combine some of these methods for the best results.


It shouldn't come as a surprise that the workers will need to be on a raised platform of some kind to ensure their safety while cleaning your roof, and scaffolding or mobile elevated working platforms (known as MEWPS in the trade) will be necessary in almost all cases. They may use a scaffolding tower or roofing ladders roped together, but it depends on the cleaning method they have selected.

Scaffolding towers are perfectly okay to use, these need to be constantly moved around, whereas full scaffolding makes a lot of sense as the contractors have easier access to the roof area. MEWPS are also handy as they can be relocated without too much hassle.

Scaffolding typically accounts for about 30% of the total roof cleaning cost, and this is generally unavoidable. Full scaffolding will cost around £18 per square metre.

The only scenario where scaffolding or a MEWP may not be needed is for conservatory roof cleaning, as the contractors won't be working at height.

Large buildings with multiple roofs can be a real challenge and may require additional equipment to reach and clean them safely. This will probably increase the total cost and extend the working time, which leads us to our next point.

Labour Costs

Each roof cleaning company sets its own rates for labour, and these will vary quite a lot depending on your location and the size of the business; a one-man roofing company will have lower overheads and only one wage to pay, so the labour cost will typically cost less than hiring a medium-sized company with several staff.

On the whole, labour accounts for the biggest chunk of your bill, at around 60% of the overall cost.


This covers items like moss killer, the odd roof scraper, replacement tiles, and minor repairs, and maybe cleaning solutions. It could also include a roof sealant if you opt for this added extra.

Even so, materials should only usually account for about 10% of the overall cost.

Roof Pressure Washer

Approximate Cost Of Pressure-Washing A Roof

With all of this in mind, here are some figures for you to consider. Although we're more interested in pressure washing here, we've included other methods for comparison.

Bear in mind that these are only rough estimates, as your own personal circumstances will have a bearing on the final overall cost of roof cleaning.

First, let's look at the average cost of roof cleaning per square metre:

  • Pressure washing - £8.50
  • Soft washing - £14
  • Steam cleaning - £11
  • Manual roof scraping (moss removal) - £11.50

Did you notice that manual scraping is more expensive than pressure washing? That's because scraping by hand is a much slower and more labor-intensive process, whereas an experienced roof cleaning company will be able to clean your roof with a pressure washer much more rapidly.

Here's another breakdown of the roof cleaning cost for different types of dwellings:

Pressure Washing 1

A Large Detached House

Between £800 and £1000

An Average-Sized Detached House

Between £600 and £800

A Semi-Detached House

Between £450 and £600

A Terraced House

Between £350 and £450

Don't forget - these are average prices for roof cleaning including all the different methods, not just pressure washing. And as the cost per square metre for pressure washing is less than the others, it's likely that your bill will be on the lower side of this scale (unless you live in London!). For more information, you can check out our post "How Much Does Pressure Washing House Cost".

What Does Roof Cleaning Involve?

You need your roof cleaned, and you want to know what it costs. But you also need to know what the process is and what to expect when the workers turn up.

Here's a general idea of what will happen.


Whether it's pressure washing or one of the other roof cleaning methods mentioned here, your cleaning session should always begin with an initial roof inspection.

Were you aware that you should have your roof inspected at least once a year, according to industry experts? If not, you're by no means alone, as most people have no idea that this is the recommendation. And this increases to twice yearly inspections for flat roofs!

For many homeowners, the initial roof inspection will be the first time it has ever been checked. The contractor will examine your roof tiles and advise you of any roof repairs that need to be undertaken before cleaning goes ahead. No reputable company will start a roof cleaning job before all the repairs have been done.

Risk Assessment

The site will be examined to identify any potential risks and hazards, and safety measures will be implemented to address these if necessary.

This is not an optional step: all professional, trustworthy roof repair or cleaning specialists will perform a risk assessment before undertaking any work. You should be very wary of a contractor who skips this part, as they are likely to cut corners elsewhere, resulting in damaged roof tiles, accidents, or much worse!

Roof Cleaning

Your roof cleaning specialists will arrive and set everything up, including any safety equipment and the tools or machines for their chosen method.

Now, pressure washers are pretty big machines - nobody wants to manoeuvre one up to your rooftop, and they'd be unwise to attempt it! Instead, a long hose is connected to the pressure washer and this is trailed up the scaffolding (or MEWP) where it is used to clear roof moss and all the other gunk.

The same applies to other methods, like Soft Washing, DOFF, and TORC systems, while roof moss removal usually only relies on hand tools for scraping.

However, pressure washing alone, although it's great for cleaning a roof, won't get rid of the microscopic spores. It may also struggle with some stubborn stains. That's why most roof cleaners apply a mild detergent before cleaning, followed by biocides afterward.

A professional roof cleaner will always make sure that your gutters are clear, and this is especially important if they use a pressure washer or jet washer (what's the difference? Fine out below!) as these will blast the moss and muck into the gutters.

Roof Cleaning

Roof Sealant

Your contractor may recommend a roof coating that will seal and protect the surface, and this is a sensible course of action. These sealants prevent moss growth and inhibit other organic matter from taking root. They protect against frost cracking and staining and will prolong the life of your roofing tiles.

If you're trying to save money, applying a sealant is a great investment as you'll avoid the financial burden of having to buy a brand new roof for much longer!

Tidying Up

So, you've got a clean roof, but a lot of that mess and muck has been distributed on the ground around your home. If you picked a reputable cleaning company, like the Tripleclean Gang, they'll do the job properly by clearing this up.

They'll also dismantle any scaffolding and safety equipment, tools, machines, and assorted cleaning paraphernalia, leaving the area clean and tidy.

How Long Will Your Roof Stay Clean?

It depends on which method your roof cleaner uses.

Pressure washing alone will only ensure that your roof stays clean for a few months or so, maybe up to a year. It's the biocides (moss killer), cleaning agents, and protective coatings that keep the dirt and moss away for longer.

If the job is done properly, it could keep your roof clean for between three and five years, although it depends on your local climate and location. Wetter areas, urban or coastal regions, and houses surrounded by nearby trees are likely to need cleaning much sooner.

On balance, it's best to book a professional cleaning session once a year, although you could really stretch this to every couple of years or so.

Pressure Washing In Roof

Why Should I Have My Roof Cleaned?

Without a shadow of a doubt, all roofs will need a good cleaning at some point. While a lot of that muck makes its way into the gutters, organic growth attaches itself to the roofing material and becomes a dirt trap.

What's more, moss absorbs moisture, adding significantly to the weight. Although it might not seem to be much of a problem, dry moss can increase its weight by as much as twenty times when wet. All this extra weight will eventually affect your roof structure and shorten its lifespan.

Excess moisture also encourages mould, rot, bacteria, and other organic growth that speeds the decay and deterioration of roof materials.

Besides this, it ruins your home's appearance, negatively affecting its value and kerb appeal.

Therefore, cleaning a roof makes a lot of sense!

Roof Pressure Washing

Why Should I Use A Professional Roof Cleaner?

At the Tripleclean Gang, we get why some people want to clean their own roofs. Maybe you need to be careful with your money. And, let's face it, who doesn't these days?

Maybe you enjoy the challenge and the sense of achievement when the job is done. It could be that you just prefer to do things yourself, and all of these are fair comments.

However, there are serious risks involved in using a pressure washer - or using any other roof cleaning method - that have to be considered before you go ahead and clean your own roof:

  • Have you used a pressure washer before? They aren't the easiest machines to work with. If you aren't careful, they will push you off balance - not the best thing when you're on a roof!
  • Pressure washing can damage roof tiles. It takes skill and experience to get the settings right and to use the machine effectively without ruining your tiles. Old tiles are especially vulnerable and can be easily broken by the high-pressure jet of water.
  • Safety precautions. Unless you're prepared to go to the expense of hiring scaffolding or a cherry picker, you'll be standing on a ladder while operating a pressure washer. This is not the best idea and is likely to result in a serious accident.
  • Roof damage. Walking on roof tiles or slate tiles requires care, not only because of the slope - and the risk of slipping - but also because they can break. Professionals use roofing ladders roped together or roof boards that spread the load evenly. They may also use water-fed poles to reach the furthest areas without having to put any pressure on the roof tiles.

Still, determined to clean your own roof? If we can't convince you otherwise, then please take all the necessary precautions. Cleaning a roof isn't an easy job, and you could end up breaking your tiles - or yourself!

In all seriousness, we would urge you to consider hiring a professional to do the job. They have the equipment, the experience, and the training to make a decent job of it and save you a lot of hard work, hassle, and pain!

Pressure Washing, Jet Washing, Power Washing - What's The Difference?

We won't dwell on this, but some people get confused over the names - even the experts! - so let's take a quick look to try and get things straight.

  • A pressure washer generally uses cold water forced through a hose and adjustable n25ozzle.
  • A power washer (also called a jet washer) mostly uses heated water. In all other respects, they are much the same as a pressure washer.

You're bound to come across those who disagree and say they want their roof power washed when they are thinking of pressure washers.

Does it really matter, when all's said and done? Probably not, as long as the customer and the cleaning company are absolutely in agreement and are on the same page! As a consumer, you have the right to know exactly what service you are paying for, and that's what really matters.

Pressure washer 1

Will Pressure Washing Ruin My Roof Tiles?

It's a fair question, as most roof tile manufacturers and roofing specialists tell you never to pressure wash roofs. In fact, some organisations don't even recognise roof cleaning as a thing*.

There's an element of truth here: you should certainly never pressure wash asphalt shingles (more common in the US than the UK), and older roofs are vulnerable to damage from aggressive forms of cleaning.

However, these warnings are generally aimed at enthusiastic homeowners who want to do the job themselves. These machines can be dangerous and clumsy in the hands of someone who doesn't know what they're doing.

Conversely, a trained, experienced professional can achieve excellent results without harming a single roof tile. They will make the appropriate adjustments to the equipment and use it expertly to clean a roof to a high standard.

*Some organisations representing roofing contractors claim that moss isn't an issue. It's worth noting that they have a vested interest here - if your roof fails before time, you'll be paying someone between £5000 and £6000, on average, for a new one.

Choosing A Reputable Roof Cleaning Company

The key to keeping costs down and getting the best results is to find a cleaning company that you can trust.

You can do this fairly easily these days, by looking at reviews on social media and trusted trader websites, like Checkatrade.

Secondly, ask for references and get them to provide insurance certificates. You might also want to ask what safety equipment they'll be using, and whether the cleaning solutions they use are harmful in any way.

No genuine, reputable company will begrudge you these requests, and you should never feel awkward or embarrassed about asking. After all, it's your money that's at risk!

Pressure Washing Roof

Roof Cleaning Prices: What To Take Away

We began by asking how much does it cost to pressure wash a roof?

And we've learned that, although it's a straightforward question, there's more to cleaning a roof than simply blasting it with a powerful jet of water.

We also discovered that people get their roofs cleaned for several reasons, but mostly as it improves the appearance and increases property value. But it goes further than this: having your roof cleaned will extend its life and save you money in the long term.

But what about the actual cost of pressure washing a roof? Well, according to the information available, you should expect to pay somewhere between £350 and £1000, depending on the size of your house, your location, and the state of your roof underneath all that moss and muck.

However, these are what are known as ballpark figures.

Will you find cheaper quotes? Of course, you will! But should you jump at the chance?

In all honesty, the cheapest quotes are rarely the best option. You need to question whether this is a genuine offer - will there be hidden costs and added extras? Are they roof-cleaning experts or just someone who does odd jobs? Do they have experience using pressure washers, or any other roof cleaning technique?

Well, now you have all the information you need to make a decision. But should you need further help, give the Tripleclean Gang a shout!

Before you go, take a look at our other articles "Will Pressure Washer Remove Oil From Driveway" and "Can You Pressure Wash Solar Panels".

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