How often should you clean your roof in Cobham?

The short answer

For a typical detached or semi-detached home in Cobham, plan a full soft wash roof clean every 4–6 years. Combine this with an annual gutter clearance (October–November is ideal) and your tiles will see out their full design life.

Properties heavily shaded by mature trees — common across Oxshott, Stoke d'Abernon and the Fairmile — may need shorter intervals of 3–4 years. Open, south-facing roofs in newer estates can stretch to 6–8 years.

Why Cobham roofs grow moss faster

Cobham sits in a damp microclimate fed by the River Mole and the surrounding woodland. Average humidity is consistently 4–6% higher than nearby Kingston or Esher, and the heavy tree canopy slows roof drying after rain.

Airborne moss spores germinate within 24 hours of finding a damp, shaded surface. North-facing pitches in Cobham can develop visible moss colonies inside 18 months of a full clean.

Signs you've left it too long

Visible green or yellow moss tufts are the obvious sign, but there are earlier indicators worth knowing.

• Dark vertical streaks running down the tiles (gloeocapsa magma algae)
• Moss fragments in your gutter — gravity has already moved them
• Damp patches on the upstairs ceiling near a chimney or valley
• Visible lichen — those flat grey/yellow circles on the tile face
• Tiles looking 'fluffy' on the edge when viewed from the garden

The cost of waiting too long

A standard soft wash on a Cobham semi-detached costs around £495. Leave it 10 years and you're looking at a full moss removal plus replacement of cracked tiles — typically £950–£1,400. Leave it 20 years and you may be replacing the entire roof at £12,000+.

Annual maintenance is far cheaper than reactive repair. We offer a £125 yearly biocide top-up plan that keeps moss at bay between major cleans.