Roofs · 3 min read
How long does roof moss treatment take to work?
What to expect after a roof moss and lichen treatment: what clears on the day, what fades over weeks, and how long the results last.
- Loose moss and mould clear on the day of a soft wash
- Lichen usually fades over several weeks to a few months
- Results typically last 2 to 3 years
Roof treatments work gradually, and that’s by design. Knowing what to expect means you won’t worry if your roof isn’t spotless the next morning.
On the day
With a soft wash before treatment, loose moss, mould and surface dirt are removed straight away. Your roof will look noticeably cleaner when we leave.
Over the following weeks
Lichen grips the roof tightly. After treatment it dies, dries out and loosens, then rain and wind wash it away. Depending on the weather and how established the growth was, this usually takes several weeks to a few months.
How long the results last
Most roofs stay clean for 2 to 3 years after a proper soft wash and treatment. Shaded roofs and those under trees may need it sooner.
Why not just blast it off?
Blasting removes growth faster but can damage your roof and usually leaves roots behind. Here’s why we don’t water-blast roofs.
Frequently asked questions
Does rain wash the treatment off?
Treatments need a dry window after application to work properly, which is why we schedule them around the forecast. After that, rain helps wash dead growth away.
Maidly looks after homes across Christchurch with eco-friendly methods and a 100% work guarantee on every service. Request a free quote.