Cheltenham gutters, specifically
Why Cheltenham gutters fill up faster than you'd think.
Cheltenham is a town of trees. The Promenade, Imperial Gardens, Montpellier Gardens, Pittville Park and Sandford Park are all lined with mature planting, and the big gardens in Battledown, Leckhampton and Charlton Kings hold trees that are often taller than the houses. From October to December that canopy comes down into gutters across the town, and a run that was clear in September can be holding a wet mat of leaves by Christmas. If your house backs onto one of the parks, or a neighbour's sycamore or chestnut hangs over the roof, twice a year is a better interval than once.
Leaves are only half of it. On older slate and stone roofs, moss comes away from between the slates and washes down into the gutter, where it packs into a dense, silty layer in the bottom of the trough. From the pavement the gutter looks fine. Up close it's a few inches of compacted material with a film of water sitting on top, which is why a vac on its own doesn't finish the job. We vac the loose material, then hand-clear what's packed into the trough and the outlets.
The housing splits roughly in two. The Regency and early Victorian centre (Montpellier, Lansdown, Pittville, the Suffolks, Bayshill) is mostly slate roofs with cast-iron gutters, hoppers and downpipes, and many terraces have a parapet or valley gutter hidden behind the front wall where nobody can see it from the street. The post-war and later suburbs (Hatherley, Up Hatherley, Warden Hill, Benhall) are mostly PVC half-round or square-line gutters on concrete-tile roofs. Different materials and different problems, but the same full clear.