Roofs are designed to bear the brunt of the elements, but their lifespan is not infinite. Like any other exterior object or surface, roofs are vulnerable to wear, tear and erosion over time.
Periodic roof maintenance can lengthen the lifespan of a roof by some 50% whilst also preventing leakage and other more expensive wear and tear.
Roof cleaning is a cost-effective way to ensure that roofs remain in good condition. Cleaning does not only benefit the structural integrity of the roof, but also drastically improves the aesthetics of the roof itself.
In this article, we’ll cover how much you can expect to pay to clean a roof and other common questions around cleaning a roof.
Average Cost of Cleaning a Roof
By compiling quotes from 8 roof cleaning specialists and roofing contractors and 8 secondary sources, we found the following average costs of cleaning a roof in the UK. All prices include VAT.
Additional costs may include:
- Gutter cleaning, repair or replacement
- Concrete repairs
- Eaves felt replacement
- Fascia and soffit cleaning
- Tile repair or replacement
Ask the roofing company about what they recommend once they inspect your roof.
|Type of Cleaning||2-Bed Terraced House||3-Bedroom Semi-Detached||4-Bedroom Detached House|
|Manual Cleaning||£500 to £600||£600 to £700||£850 to £1,000+|
|Pressure Washing||£600 to £750||£700 to £850||£950 to £1,100+|
|Cleaning With Biocide Treatment||£800 to £1,100||£900 to £1,200||£1,150 to £1,500+|
|Cleaning With Biocide Treatment and Sealant||£1,200 to £1,500||£1,000 to £1,500||£1,200 to £1,750+|
|Additional Cleaning and Repairs to Tiles and Guttering||+£150||+£200||+£450+|
Why Should You Clean Your Roof?
When we talk about the cost of roof cleaning, we’re talking primarily about two things:
- The build-up of moss and other thick plant foliage
- Discolouration from algae, fungus and other dirt
Moss and other plant matter are more serious as they can lead to increased water retention, thus making the roof heavier and more likely to suffer serious damage including collapse, in the most extreme cases at least.
Moss can also force tiles apart and intrude underneath the tiles, allowing water to seep beneath tiles and into the house’s foundations.
Needless to say, water that intrudes into your home has the potential to be hazardous, dripping down through the interior walls into the electrics or rotting the timber frame and beams.
You’d be amazed at how even small amounts of moisture intrusion can cause damage to a home over time. Leaky roofs can also cause a build-up of hazardous black mould.
Besides structural damage, dirty roofs are unsightly and really affect the curb appeal of a home when selling. For a reasonably small investment, it’s possible to clean a roof in its entirety, removing potentially damaging moss and algae in the process.
Also, roof cleaning may reveal other issues with the roof ranging from missing tiles to problems with guttering, e.g. blocked or otherwise dysfunctional guttering.
Types of Roof Cleaning
There are 3 broad techniques available for cleaning roofs:
Manually, using brushes
This involves scrubbing the roof with wire or fibre brushes. Strong detergent will be used to loosen dirt and kill algae/fungus. This might be enough if a roof is just slightly discoloured but relatively free from moss overgrowth. Manual removal of moss and other foliage by hand is suitable for fragile roofs that are unsuitable for pressure washing. Most firms will prefer to pressure wash the roof, though.
With pressure washers
The most common and popular type of roof cleaning service, pressure washer roof cleaning involves the use of pressurised water jets that effectively remove stains and foliage.
Pressure washers are extremely effective at removing dirt and moss from hard surfaces like tiles. Pressurised water jets can also effectively reach into the cracks and crevasses of a roof.
The contractor will start at the highest point of the roof and work downwards. If necessary, plastic sheets will be thrown across the garden to collect moss and other foliage. It might also be necessary to disconnect the guttering to prevent loose moss from blocking it up.
Either manually or with pressure washers with additional biocide/herbicide treatments for killing moss
To prevent the rapid re-growth of moss, algae and fungus, the roofing company may recommend treating the roof with fungicides or herbicides (i.e. biocides).
This will kill moss, algae and fungus, preventing them from quickly growing back. Once herbicide/fungicide has been applied, the company will usually have to wait a day or two for it to take effect before coming back and removing any growth before washing the roof.
It’s also possible to seal the roof against further moss or algae intrusion. Sealants can be sprayed onto the roof, helping prevent moss and algae intrusion. It’s relatively simple once a roof has been cleaned and can greatly enhance the roof’s resistance to further growth.
Whilst it’s possible to clean a roof DIY, it’s obviously a risky business without the proper training or equipment. Whilst some roofs are easily accessed via ladder, others aren’t, and it’s difficult to tell the structural integrity of a roof before you set foot on it, unless you’re an expert.
Professional roof cleaning is well worth it for peace of mind over one’s personal safety, and as far as administering herbicide/fungicide and sealing the roof goes, the experience of a roofing contractor is indispensable.
A Note on Cleaning Thatched Roofs
Thatched roofs are a different beast from tiled roofs and require regular specialist cleaning with particular attention given to mossy buildups, fungus and algae.
Without regular maintenance, thatched roofs can retain vast quantities of excess water and may rot internally. Thatched roofs also need to be re-tightened to ensure their integrity.
Rightmove says thatched roofs cost around £1000 to maintain per year on average.
Step-by-Step Roof Cleaning
The expected roof cleaning process as broken down step-by-step is as follows:
- The first step is invariably an assessment of the roof. What state is the roof in? Does it need urgent repairs prior to cleaning? The roof cleaners will also inspect access to the roof and decide whether ladders will suffice or whether scaffolding will need to be erected (usually only necessary for larger roofs).
- If broken tiles are found, now is an ideal time to replace them. Broken tiles usually cost around £50 to £75 to replace per tile when repaired as part of a roof maintenance service.
- The ground around the roof will be covered with plastic or tarpaulins to catch dislodged debris.
- The guttering is usually disconnected prior to roof cleaning.
- If required, the roof will be treated with biocide/fungicide/herbicide and left until the chemicals take effect.
- The roof will then be washed, either by hand, with pressure washers, or a combination of the two.
- Gutters can also be washed if necessary.
- If necessary, sealant can be applied to the joints between roofing tiles.
- Reassembly and cleanup.
How Long Does it Take to Clean a Roof?
The actual roof cleaning process will seldom take more than 1 day.
However, if the roof is being treated with a biocide and/or sealed, then this will usually stretch works over 2 days at least. The roof will have to dry out before sealant is administered, which can pose a problem during wet weather.
When is the Best Time to Clean a Roof?
Always aim to carry out roof maintenance and repairs in the dry summer months. This will make the entire process easier since moss and other foliage will be drier and easier to dislodge. The later summer months or early autumn is probably ideal.
This also applies to thatched roofs which should also be maintained and cleaned in the summer where moisture levels are lower and temperatures are higher.
How to Find a Roofer
Whilst there are specialist roof cleaning and maintenance services around, most roof cleaners will also be general roofers by trade.
Always look for some with a strong portfolio of recent work and a long-term local reputation. Don’t be tempted by cold callers or contractors that offer a discount because ‘they recently completed a job in the area’ (unless you can verify this).
Look for roofers that are accredited by the National Federation of Roofing Contractors (NFRC). Where sealant or biocide is recommended, ask what brand of products are being used and whether they come with a guarantee.
Get Pricing on Roof Cleaning Near You
We’ve done our best to give you a good idea of what you can expect to pay to clean your roof.
However, our guides are not a substitute for a fixed quote specifically for you.
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