Roof cleaning quotes vary more than almost any other exterior job, and the reason is usually method rather than margin: two quotes for the same roof can describe two completely different pieces of work, one finished in an afternoon and one that keeps working for years.
This guide explains what genuinely drives the price, why the cheapest quote often costs more in the long run, and what any quote should tell you before you accept it.
Why there's no fixed price for a roof
A roof is difficult to price accurately without seeing it, which is why we survey before giving a figure. Roofs differ in ways that change the work substantially — a steep, complex roof with three valleys and heavy lichen is a different job from a simple bungalow with light green algae, even if the two properties look similar from the street.
We survey the roof before quoting and then give you a fixed, no-obligation figure. A firm price after a proper look is more useful than a low number that moves once someone is on site.
What actually changes the price
- Roof area and pitch — the biggest single factor. A steeper roof takes longer and needs more care
- Tile type — old clay peg tiles, slate and pantiles all need a gentler approach than modern concrete interlocking tiles
- How established the growth is — light algae is a treatment; thick moss pads that have been building for a decade need physically removing first
- Roof shape — valleys, dormers and multiple elevations add far more roof area than the frontage suggests
- Access — conservatories, extensions, tight side returns and dense planting all slow the work down
- Whether gutters are included — moss dislodged from a roof lands in the gutters, so a proper job clears them afterwards
- Location — we cover ME1–ME17 and CT1–CT4 without a travel surcharge
Soft washing versus pressure washing — the real cost difference
This is where quotes diverge most. A pressure washer will strip moss off a roof quickly and cheaply. It will also blast the protective granular surface off concrete tiles, force water up under the laps, and risk lifting or cracking older tiles that have spent decades bedding in.
The roof looks clean for a season. Then the growth returns faster than before, because the surface is now rougher and holds more moisture. A cheaper clean that shortens the life of the roof is not really a saving — which is worth weighing up when you compare quotes.
Soft washing costs more up front because it takes longer and uses a biocidal treatment rather than brute force. It works at low pressure, kills the growth at the root, and keeps working for weeks after we leave. On most Kent roofs the result stays visibly clear for four to six years. Measured per year of clear roof, it is usually the cheaper option — and it does not put the tiles at risk.
What any roof cleaning quote should include
- A survey before the price — not a figure quoted blind over the phone
- The method, stated plainly — soft wash or pressure wash, and why that suits your tiles
- Moss removal as well as treatment, where the build-up is heavy enough to need it
- A gutter clear-down afterwards, since that is where the dislodged moss ends up
- Proof of public liability insurance, before anyone starts work at height on your property
- A fixed price, not an estimate that can move once the work starts
A quote covering all six is describing a different job from one that doesn't, even where the headline figures look close.
Is roof cleaning actually worth it?
For appearance alone, that is your call. For the roof itself there is a reasonable case: moss pads hold water against the tile, lift edges as they thicken, and shed constantly into the gutters — so a mossy roof frequently causes the blocked-gutter problems that lead to damp, stained fascias and rotten timber.
The honest answer is that it is maintenance rather than an emergency. If your roof is sound and lightly marked, it can wait. If moss is visibly thick, sitting in the valleys and filling the gutters below, it is doing something rather than just looking untidy.
How we quote
Every quote is free, individual and no-obligation. We look at the roof rather than guessing from a postcode, tell you what the job involves and which method suits your tiles, and give you a fixed figure before any work starts.
We are City & Guilds trained, Checkatrade-listed and fully insured with public liability cover, and we are happy to provide proof of insurance before a job. You can read more about the method on our roof cleaning page, or see the village-by-village detail on our Maidstone roof cleaning page.