New estates & the conservation area
A new-build on Copcut and a Tudor house on Friar Street — two different jobs.
Most of Droitwich's recent growth has been modern concrete interlocking tile — Copcut, Yew Tree Hill and the in-fill developments around them. New owners often assume a ten- or fifteen-year-old roof is too young to need anything doing. In the dry it might be; in the Salwarpe valley it isn't. Concrete tile leaves the factory with a thin surface coating, and once that coating starts to weather — which in this damp air happens sooner than the brochure suggests — the slightly porous, textured surface underneath gives algae and moss spores something to grip. You first see it as black streaking on the north-facing pitch, then green creeping up from the gutter line. Treating it early, with a soft-wash and biocide while the tile is still sound, is the cheapest and gentlest point to act: it lifts the growth, slows how fast the tile weathers, and keeps the roof looking like the day it went on.
The town centre is the opposite end of the scale. The Droitwich Spa conservation area takes in around 46 listed buildings — among them two Grade I and two Grade II* — across the Tudor and Georgian streets: Friar Street, the High Street, St Andrew's Street, Queen Street and the lanes between. A good number of those roofs are old clay, stone or slate on timber frames, and the famous lean of the High Street buildings is no accident — the ground beneath the centre has subsided for centuries over the brine and salt workings that made the town. That history is exactly why these roofs need the lightest possible hand. On them we hand-scrape only, never pressure, because force cracks old tile, drives water into a structure that has stayed watertight by careful balance, and can disturb a roof already carrying the strain of subsidence.
For listed buildings, cleaning sits in a careful zone. Straightforward removal of biological growth normally doesn't need listed-building consent, because you're not altering the fabric of the building. Anything that touches mortar, lead or the original tile-fixing usually does — and we'll tell you upfront if a job crosses that line so you can speak to Wychavon District Council's conservation team before booking. We keep biocide off lime mortar by sheeting and rinsing the edges, and where old lead flashings have weathered to a soft grey patina we'll usually recommend leaving them rather than scrubbing them back to bright metal — exactly the kind of thing heritage officers, reasonably, don't want to see.
At quote stage we check whether your property looks listed and glance at the Historic England map before the survey, and on the older streets we look at whether the roof has moved with the subsidence so we can plan access safely. It costs us a few minutes and can save you a headache.