The best time of year to clean a roof

Month by month

Why nesting season matters

Roofs are popular nesting spots in spring and summer: gutters, gaps under tiles, behind fascias and in chimneys. The RSPB says "March to September marks the main nesting season", although some birds start in January or February and others breed into late September. Under the Wildlife and Countryside Act 1981, it's illegal to "deliberately take, damage or destroy the nest of any wild bird while it is in use or being built".

NFRC, the roofers' trade body, is clear with its members: "If you know that birds are nesting, you mustn't start roofing work." It also advises asking your roofer whether they check for nests before starting. Booking outside the main season avoids the problem altogether.

Why after the leaves fall

Moss removal sends moss, grit and debris into the gutters, so the gutters need clearing straight afterwards. Do the roof before the trees have finished, and the gutters fill again within weeks. Do it after, and one visit clears both for the winter. Our tree-by-tree guide shows when the leaves are usually down for oak, beech, lime and pine.

Picking the day: weather

• Dry spells matter if a treatment is going on. Product labels set the conditions. Wet & Forget, for example, says to apply when "there won't be any rain for at least 4-5 hours".
• Frost and ice make a roof dangerous, and a mossy slope holds moisture, so it can stay slippery.
• Strong wind is unsafe at height, and blows moss, debris and spray where it shouldn't go.
• Heavy rain makes roof work unsafe, and washes treatments off before they can work.

So a roof clean is booked for a window, not a fixed date. A good roofer will move the day for the weather rather than work in conditions that aren't safe.

What about summer?

Summer is dry and the days are long, so it's tempting. But it's the middle of nesting season, and a roof that looks empty from the garden can have nests tucked under tiles or in the gutters. If a summer clean can't wait, for example because moss is blocking gutters and causing a leak, have the roof checked for nests first, and accept that some areas may need to wait until the birds have gone.

Combining it with other jobs

• Clear the gutters and downpipes in the same visit, since that's where the moss ends up.
• Have any slipped tiles or loose ridges looked at while the roof is being worked on.
• If you're selling in spring, a winter clean means the work is done and photographed before the house goes on the market.

When we clean roofs

We recommend booking roof cleaning from late autumn through winter, after the leaves are down and outside the main nesting season, and we pick the day by the forecast. We take the moss off by hand from roof ladders, treat where it suits the roof, clear your gutters and downpipes, and photograph every slope before and after.

Written by Hawkes Roofing, roofers based in St Albans who remove roof moss by hand across Hertfordshire, Buckinghamshire and north-west London. Last reviewed 26 October 2026.