What's included in a roof clean
A typical job starts with a look at the roof to check the covering, pitch and how much moss or algae has built up, followed by removal of moss and debris and a wash or biocide treatment to the whole roof. Some installers include a gutter clear as part of the job; others price it separately, so it's worth asking.
Soft wash and pressure wash methods
Soft washing uses a low-pressure biocide treatment that kills moss and algae without disturbing the tiles — generally the gentler option for older concrete, slate or clay roofs. Pressure washing physically blasts moss away faster but carries more risk of dislodging tiles or stripping granule coatings on aged coverings.
Ask which method an installer plans to use, and why, particularly if your roof is older or already showing cracked or slipped tiles.
Access and safety
Roof cleaning is work at height, and how it's accessed depends on the height and pitch of your roof — a ladder may be enough for a bungalow, while a two- or three-storey house usually needs a tower or scaffold. The Health and Safety Executive publishes guidance on the precautions that should be taken for any work at height, and it's reasonable to ask an installer how they plan to access your roof safely.
After the clean
Moss and algae can return over time, particularly on shaded roofs or those under trees, so don't be surprised if some regrowth appears eventually. Some installers apply a treatment intended to slow regrowth; ask what's included and how long it's expected to make a difference before you compare quotes.
Frequently asked questions
How long does a roof clean take?+
It depends on the size, pitch and access to your roof — the installer you're matched with can give you a more accurate idea once they've seen it or discussed it with you.
Will cleaning damage my roof tiles?+
Done carefully, no — but the method matters. Ask whether an installer plans to soft-wash or pressure-wash, especially on an older roof, since pressure washing carries more risk on aged tiles or slates.
Do you clean flat roofs as well as pitched ones?+
Mention your roof type in your enquiry and we'll match you with an installer who covers that type of work.
Can I have just the moss removed without a full wash?+
That's a question for the installer directly — some offer a moss-removal-only option, others prefer to treat the whole roof. Ask when they get in touch.
Useful local links
- Portsmouth City Council – Planning and Building Control — Planning and building control guidance for Portsmouth, including Tipner and the rest of Portsea Island.
- Havant Borough Council – Planning Services — Planning services covering Havant, Waterlooville, Emsworth, Purbrook, Langstone, Warblington and Hayling Island.
- Fareham Borough Council – Planning — Planning information for Fareham, Stubbington and Funtley.
- Winchester City Council – Do I Need Planning Permission — Guidance for Southwick, Denmead and North Boarhunt, which fall within the City of Winchester district.
- Gosport Borough Council – Planning — Planning information for Gosport.
- Health and Safety Executive – Working at Height — Official guidance on the safety rules that apply to any work at height, including roof work.