What's involved
A typical roof clean starts with a look at the roof from ground level and, where access allows, up close, to see how far the moss has spread and whether any tiles look lifted or cracked underneath it. From there an installer removes the growth by hand or with soft-bristle tools rather than jet-washing, then applies a biocidal treatment to slow regrowth.
Moss vs algae vs lichen
Moss is the thick, cushiony green growth that holds the most moisture and does the most damage over time. Algae shows up as a duller green or black streaking, often below chimneys or on north-facing slopes, and lichen appears as flatter, crusty patches that can be slower-growing but harder to shift. An installer can tell you which you've actually got, since the right approach differs.
Gutters and downpipes
Moss debris that washes down the roof is one of the main causes of blocked gutters, and a blocked gutter overflowing at the fascia is how a lot of damp problems start at roof level. It's worth asking whether gutter clearing is included in a roof clean or quoted separately.
When cleaning isn't enough
If moss has been left for years, it can lift tiles out of position or let water track under the covering, and cleaning alone won't fix that — a repair or partial re-tiling might be needed instead. A local installer should tell you honestly if that's what they find rather than just cleaning over a bigger problem.
Frequently asked questions
How often does a roof need cleaning?+
It depends entirely on the roof's aspect, pitch and how shaded it is — a north-facing roof under trees will need attention far more often than an open, south-facing one. An installer can advise based on how your particular roof looks.
Can moss be prevented from coming back?+
A biocidal treatment applied after cleaning slows regrowth, and keeping overhanging branches trimmed back reduces shade and leaf debris, but no treatment stops moss returning permanently in a damp climate.
Is it safe to clean my own roof?+
Any work at height carries a real risk of falls, which is why the Health and Safety Executive's guidance flags it as a recurring cause of serious injury on both domestic and commercial jobs. It's not something to take lightly without the right access equipment and experience.
Useful local links
- Basingstoke and Deane Borough Council — Planning — The local planning authority for Basingstoke and most of the surrounding villages in this cluster; covers when planning permission is needed for roof work beyond routine cleaning.
- Basingstoke and Deane Borough Council — Building Control — Covers building regulations approval for roofing work that goes beyond like-for-like repair or cleaning.
- Hart District Council — Planning and Building Control — The local planning authority for Hook, which sits in the Hart district rather than Basingstoke and Deane.
- Planning Portal — Roof Work — National guidance on when roof alterations need planning permission, referenced when explaining that routine cleaning doesn't.
- Health and Safety Executive — Working at Height — HSE guidance on the risks of working at height, referenced when explaining safe roof access.