Roofs
How to keep moss off your roof for longer
Leo Grant
· 5 min read
Best season
Autumn
How often
Every 3–5 years
DIY difficulty
Not a DIY job
Pro time
3–6 hours
Scraping is only half the job
Removing moss by hand clears what you can see, but the spores and roots stay in the tile surface and grow back within a season.
What a biocide treatment does
A soft wash biocide kills the remaining growth and keeps working for months after it’s applied, so the roof stays clear for years.
Never pressure wash a roof
High pressure strips the protective surface of tiles and forces water underneath them. It’s the fastest way to shorten a roof’s life.
The same wall, before and after one soft wash.
Key takeaways
Hand removal plus a biocide treatment lasts years.
Never use high pressure on tiles or slate.
Autumn is the best time to treat a roof.
Keep reading
More from the journal.
House care
How often should you clean your render?
Algae comes back on a cycle. Here’s how to spot it early and how often a soft wash really needs doing.
Guides
Pressure or soft wash: which does your surface need?
Concrete loves pressure. Render, roofs and timber don’t. A quick guide to matching the method to the surface.
Seasonal
A spring checklist for the outside of your home
Ten small jobs that stop winter grime turning into summer stains.