Malvern roofs, specifically
Why Malvern roofs green up faster than almost anywhere we work.
Malvern isn't built on flat ground — it's built up the side of a hill. The town climbs the steep eastern flank of the Malvern Hills, with the streets stepping from roughly 50 metres above sea level near the Link up to around 200 metres on the higher terraces, all of it on the shoulder of a ridge that rises to 425 metres at the Worcestershire Beacon. That geography is the whole story for roofs here. A large share of the pitches face north or west, into the shadow of the hill and the AONB woodland that cloaks the lower slopes, so for much of the winter the sun barely touches them. They never get the chance to dry out.
Then there's the weather. Malvern averages around 740mm of rain a year, spread across roughly 123 days when more than a millimetre falls — and because the town sits against the hill, cold, damp air drains down into the valleys and pockets and lingers. A roof that stays wet for days at a time is exactly what moss, lichen and gloeocapsa algae need. The result is that a slate roof in Malvern Wells or on the shaded side of North Malvern will carry noticeably heavier growth than an identical house out on open, drier ground towards Worcester or the Severn vale.
And the roofs themselves make it worse. Malvern's prosperity came in the Victorian water-cure boom, when wealthy families — many of them from the booming Birmingham area — built large Regency, Victorian and Edwardian villas and hotels up the hillside for the hydrotherapy season. A great many of those roofs are natural Welsh slate or old, porous clay: complex, steep, multi-pitched, with valleys, turrets and shared parapets that hold damp and shed it slowly. Welsh slate is wonderfully durable but it splits along its bed if it's ever hit with pressure, and old clay loses its weathered surface the same way. These are roofs that must be soft-washed and hand-stripped, never pressure-blasted.
Down the hill it's a different roof but the same problem. The post-war and modern estates around Malvern Link, Link Top and the Pickersleigh side are largely concrete interlocking tile — Marley and Redland — and the textured surface grips spores so hard that in this damp microclimate whole roads of them mat up green together. Whether it's an 1860s spa villa on Abbey Road or a 1970s semi off Pickersleigh Road, the cause is the same hillside damp, and the cure is the same: lift the moss off by hand, then treat the cause with biocide so it stays off.
One thing worth saying plainly: this isn't a town where a quick blast and a rinse does the job. The damp comes back fast on these slopes, so a roof that's only been pressure-washed is green again within a season or two — and on slate that pressure has done quiet damage you'll pay for later. Manual moss removal plus a proper biocide is gentler on the material and lasts far longer, which is exactly why we work the way we do here.