Why Guildford Roofs Get Moss Faster
Guildford's geography creates several moss-accelerating conditions that don't apply equally across Surrey. Properties in the Wey Valley — Burpham, Shalford and Bellfields — experience persistently higher humidity from the river corridor, driving faster spore germination and growth on all aspects. Properties on elevated slopes at Merrow and Worplesdon face extended periods of shade on north-facing slopes that never fully dry between rainfall events. Mature tree canopy throughout Onslow Village and the established suburbs keeps tile surfaces damp and reduces UV exposure that would otherwise limit moss growth.
Why You Should Never Pressure Wash a Roof
Pressure washing is the single most damaging thing you can do to a clay or concrete tile roof. The high-pressure water jet forces water between tiles and under the felt, saturates the roof structure, breaks down the surface coating on concrete tiles removing their weather resistance, and physically chips and erodes clay tile surfaces that have been hardened over decades of weathering. A biocide treatment kills moss at the root system and allows it to die and detach naturally over the following weeks. The roof is cleaned without any mechanical damage to the tile surface.
Our Moss Treatment Process in Guildford
We apply a professional-grade biocide wash to the full roof surface from the ridge to the eaves. The biocide penetrates the moss and lichen at root level, killing the growth without mechanical disturbance. Dead moss detaches naturally over 4–8 weeks as rainfall washes it from the slope. We then apply a sealing treatment to the ridge mortar and point up any failed sections identified during the treatment visit. A single biocide treatment typically provides 3–5 years of suppression before re-treatment is needed, depending on local conditions.