01/11/2026
🏠 Is roof cleaning only about improving its appearance?
A professional roof clean can completely transform the appearance of a property, but there are practical reasons for removing a heavy build-up of moss too.
Moss acts like a sponge, absorbing rainwater and keeping the roof wet for longer. Large amounts can obstruct the channels and joints between tiles, slow down the flow of rainwater and eventually fall into gutters, valleys and downpipes.
❄️ What happens during cold weather?
When wet moss holds moisture against the roof, that moisture may enter existing pores, worn surfaces or small cracks in older tiles. When temperatures fall below freezing, the water freezes and expands. Repeated freezing and thawing can gradually worsen existing weaknesses, potentially leading to flaking, cracking or deterioration of vulnerable tiles.
☀️ What happens during warmer weather?
During hot and dry weather, moss can dry out, shrink and appear dead or dormant. Pieces may loosen and fall into the gutters, but the moss can become active again when damp conditions return. Roofs that are shaded, north-facing or close to trees usually remain damp for longer and are therefore more likely to experience regrowth.
Some of the benefits of a professional roof clean include:
✅ Removes heavy moss, algae, lichen and accumulated dirt
✅ Helps rainwater travel down the roof more freely
✅ Reduces the amount of moss falling into gutters and downpipes
✅ Helps gutters and roof valleys remain clear
✅ Reduces prolonged moisture retention against the tiles
✅ Reveals broken, slipped or deteriorated tiles that moss may have concealed
✅ Makes it easier to inspect ridge tiles, pointing, flashing and other roof details
✅ Can greatly improve the appearance and kerb appeal of the property
✅ A suitable biocide treatment can slow biological regrowth and continue working after the initial clean
Roof cleaning must be completed using a method suitable for the roof covering. Excessive pressure, unnecessary walking and aggressive scraping can damage tiles, force water beneath the overlaps or remove the surface finish from certain concrete tiles.
At Alfa Exterior Cleaning and Services, we assess the roof first and use a careful, low-pressure approach suitable for its condition. As a fully trained roofer, I can also identify visible defects and discuss any repairs that may be required.
Every roof is different, and a small amount of harmless surface growth does not always mean that cleaning is necessary. We provide honest advice based on the amount of moss, the condition of the tiles and whether drainage is being affected.
📍 Covering Colchester and the surrounding areas
📩 Message us for a free quotation
Fully trained roofer • Trained to work at height • Fully insured • Accredited in exterior cleaning
Goodbye grime, hello shine. ✨
