Roof cleaning prices look simple until you start collecting quotes. One firm gives a flat sum for the house. Another prices by the square metre. A third includes a treatment to slow the moss returning and a fourth does not. This guide sets out the ranges published by national cost guides, split by roof covering and by cleaning method, followed by the factors that push a price either way on a real house: roof area, reach, the amount of growth and the fragility of the covering. Because the ranges are national, treat them as a yardstick for reading a quote. On an older roof in or around Bath the covering and the access usually matter more than the area. Your own figure comes after a survey, when we have seen the roof and photographed what is growing on it.
What cleaning costs by roof covering
The simplest way to size a roof cleaning job is by the covering, because slate, clay and concrete tiles and flat membranes all clean differently. MyBuilder's roof cleaning cost guide (2026) reports the typical UK ranges below, and puts the starting point for any clean at about £300.
| Roof type | Typical UK range |
|---|---|
| Flat roof | £300 to £600 |
| Pitched roof | £450 to £850 |
| Tiled roof | £400 to £750 |
| Slate roof | £500 to £1,000 |
The table shows roughly where a sensible price sits. Each row is wide because roofs differ so much inside a single category, and your own price is set after the survey.
Slate sits at the top of the range for good reasons. Natural slate is thin and brittle at the edges, it is nailed rather than hung on lugs, and a careless boot or brush can crack it. The work is slower and the person doing it has to place every step on the roof with care. Tiles are more forgiving, though old clay tiles can be as fragile as slate once their surface has weathered. Flat roofs are cheaper to clean because there is less area to cover and no laps to work around, yet the membrane still needs a method that does not scour it. That applies to felt, to EPDM (a rubber sheet) and to GRP, which is glass-reinforced plastic.
A table by covering also hides something useful: price follows the risk to the roof as well as the time on it. A cheap clean that leaves cracked slates behind is not cheap.
Soft wash and pressure wash rates per square metre
Some firms quote by area instead of by the roof. The same MyBuilder guide (2026) gives typical UK rates of £15 to £20 per square metre for soft washing and £10 to £15 per square metre for pressure washing. These help you compare offers, and a fixed quote only comes after the survey.
At first glance the pressure-wash figure looks like the bargain. It is the lower rate, and the jet strips growth quickly. Yet that guide warns that a jet wash may damage delicate tiles, and the warning matches what we find on site. A jet can lift the surface off concrete tiles, drive water up under the laps of slates and tiles, and loosen mortar at the ridge. The cost of putting that right is far higher than the saving on the clean. The mechanics are laid out in the damage a jet wash can do to tiles and slate.
Soft washing is priced higher because the method has more steps. A low-pressure spray puts a cleaning and biocidal solution (a treatment that kills moss, algae and lichen) on the roof. It is then left to work, and the dead growth is rinsed or brushed away gently. The time on site and the products both cost money. What you get for the difference is a clean that does not rely on force, and a surface that stays clean for longer because the roots and spores have been treated, not simply blasted off.
It is worth asking any firm quoting by area what their rate includes. Some count only the visible slopes and some include the hips, valleys and the tops of chimneys. Some add a charge for the second visit when the treatment is left to work. Comparing a per-metre rate with a flat sum only works if the same scope sits behind both.
House type, roof shape and access
The table by covering assumes an ordinary roof that can be reached without fuss. Real houses vary, and on the survey these are the things that change the figure.
Size and shape
A small terraced house has two slopes and a short ridge. A detached house with a hipped roof (one that slopes on all four sides) has more slopes and more edges to work along. A Victorian villa may add bay roofs, dormers and a valley, where one slope drains into another. Each of these adds time, and a valley full of moss and leaf litter takes longer than the slope either side of it.
Height and access
A single-storey extension can be cleaned from a ladder. A three-storey terrace in Bath often cannot, and the cost of scaffold or a tower can rival the cost of the clean. If the street is narrow, if there is a basement area to bridge, or if a neighbouring roof must be crossed, say so when you enquire. Access is a frequent reason for a wide gap between quotes on one house.
How much is growing there
A light film of algae takes less effort than a thick cushion of moss with debris trapped beneath it. Thick moss often has to be removed by hand before any treatment can reach the surface, and that is slow work. Our guide to removing moss from a roof explains how hand scraping, brushing and biocide fit together.
Gutters and fall-out
Moss that comes off a roof ends up in the gutters. A sensible quote includes clearing the gutters and taking the debris away, and it should say so without trade jargon.
What a fair cleaning quote should list
Totals that look alike can hide very different work, so read the detail as well as the sum. A fair written quote for a roof clean names each of the following, and a missing item deserves a question.
- The method: soft wash, hand removal, brushing, or a combination, and which parts of the roof get which.
- The treatment: that a biocide is applied and left to work, and the product used.
- Which slopes, hips, valleys and ridges are included.
- Access: ladders, a tower or scaffold, and who pays for it.
- Gutters, downpipes and flat roof outlets: whether they are cleared.
- Debris: that moss and waste are taken away and the site left clear.
- Any repairs found on the way, priced separately and agreed before they are done.
That last point is worth dwelling on. A roof cleaner is often the first person to get close to your roof in years. Cracked slates, slipped tiles, perished ridge mortar and lifted lead flashings show up once the cover of moss is gone. A good firm tells you, shows you a photograph and prices the repair as a separate item. A firm that quietly adds charges on the day, or says nothing, leaves you with a clean roof that still leaks.
After the survey we write the scope down and attach pictures taken on your roof, which lets you check our list against anyone else's. Ten years of workmanship cover come with the work, in writing.
The cost of cleaning against the cost of leaving it
Moss costs little to treat early and a good deal to ignore. Wet cushions press against the covering, growth works between the laps and lifts the edges, and clumps drop into the gutters. The mechanism has its own page, does moss damage a roof, so here we stay with the money.
A roof clean in the ranges above is a small fraction of the cost of replacing a roof. MyBuilder's new roof cost guide (2026) puts a typical UK roof replacement at £5,000 to £12,000. MyBuilder's 2026 slate roof guide gives typical lifespans of 30 to 50 years for concrete interlocking tiles, 40 to 60 for clay plain tiles and 75 to 100 or more for natural slate, all depending on exposure, workmanship and maintenance. Keeping a roof clean and the gutters flowing is part of what lets a covering reach the upper end of those ranges.
That does not mean cleaning is always the right answer. A roof whose tiles are crumbling, whose slates have lost their nails or whose underlay has perished will not be saved by a wash, and repair or renewal is the better use of the money. Part of the survey is deciding where your roof stands. A roof that needs a clean gets a clean price. A roof that needs more gets photographs of the evidence before anything is agreed. We weigh that decision in more detail on the whether to clean or replace a roof page.
Stone, slate and listed roofs
Older roofs cost more to clean because there is less margin for error. Natural stone tiles, common on older buildings around Bath, are porous and can be fragile. Their surfaces flake under force, and a single cracked tile may be hard to replace with a match. Gentle methods, hand work and a low-pressure rinse are the only sensible choices, and the job takes longer. Our guide to cleaning stone roofs goes through the approach in detail.
Heritage status adds a different kind of cost. Heritage rules shape what is sensible here. UNESCO recognises the entire city, the city-wide conservation area reaches across about half of that ground, and plenty of houses are listed. For those, B&NES Council asks owners to contact its planners ahead of any works, and treats unconsented works as an offence. A clean is not a repair, but it is sensible to ask the council whether a particular treatment on a listed roof needs consent. It costs nothing to check and it may save a great deal.
Treatment choice matters on heritage roofs too. Harsh chemicals can stain stone and pit lead, and runoff can mark the walls below. We choose a treatment to suit the covering, protect the lead and the surrounding stonework, and keep the run-off away from plants and drains as the product instructions require. Where a roof is fragile enough that cleaning would do more harm than good, we explain that and suggest a repair or a more cautious approach, even when that means a smaller job for us.
Turning a price range into a fixed price
A published range tells you if a figure is believable. It says nothing about your roof, and only a visit does that. We go up, or use a tower where the height demands it, and examine the covering, the ridge and hips, the lead, the gutters and how much growth there is. We photograph what we find and send the pictures with the quote so you can follow the reasoning.
The survey costs nothing. Afterwards you get one fixed price on paper, with the method named, access sorted and any repairs as separate lines. There is no pressure to book, and a clear explanation is part of the service. If a gentle clean will do, we recommend exactly that and nothing more. If we find defects, we will say which ones matter now and which can wait, and we will not let a cleaning visit turn into an unrequested roof replacement.
To work out the right clean for your roof, start with the type of covering and the age of the house. A modern concrete-tiled semi is a simple job. A pre-war slate roof on a three-storey terrace is not. Tell us which you have when you ask for a survey, and we can plan the access before we arrive. You will find the whole service laid out on our roof cleaning and moss removal page, and bookings are taken on 01225 285181, by WhatsApp, or through the enquiry form on this page.