Inspired by a helpful UK roofing guide. This walk-through is based on the popular video "How to Clean and Get Rid of Roof Moss For GOOD", which covers the full process from assessing the extent of growth right through to the treatment that keeps moss away. Solid, practical content — well worth watching before you get the ladder out.
1. Assess the roof from the ground first
Stand back and look at the whole roof with a pair of binoculars. You want to know how much coverage there is, whether any tiles look lifted or cracked, and which areas drain towards which gutters.
If tiles are already slipping or you can see daylight from inside the loft, that changes the job. Get a roofer to look before you attempt any cleaning. Cleaning a structurally dodgy roof makes it worse, not better.
2. Gather the right equipment
You'll need: a good-quality extending ladder, ladder standoffs (so the ladder rests against the guttering brackets rather than bending the gutter), a long-handled soft brush, a garden sprayer or a moss killer spray, and a biocide treatment rated for roofs.
Do not use a pressure washer directly on tiles — especially concrete or older clay tiles. The force strips the surface coating, blasts mortar out of the verges, and forces water behind tiles. A soft brush and chemistry does the job properly.
3. Set up safe access
Tell someone you're going up. Seriously. Working at height on your own is a bad idea. Set the ladder at the right angle — roughly one metre out for every four metres up — and use the standoffs to keep the top stable and off the guttering.
Roof ladders (ridge hooks) let you work on the slope itself rather than leaning out from the eaves. Hire one if the moss goes high. They spread your weight and prevent tiles from cracking underfoot.
4. Brush off loose moss working top to bottom
Starting at the ridge and working down, use a long-handled soft brush to loosen and sweep the bulk of the moss off the tiles. Work in straight strokes down the slope, not across it.
Don't be tempted to blast everything into the gutters — you'll block them. Bag up the loose material as you go, or spread a tarpaulin below to catch it. That said, some bits will inevitably end up in the gutters, which is why step six matters.
5. Apply a biocide moss killer
Once the loose growth is off, apply a dedicated roof biocide. These are specifically formulated to kill the remaining spores, lichen, algae, and the roots of any moss that's gripped into the tile surface.
Apply on a dry, calm day — you want the product to soak in, not blow back in your face or wash straight off in a shower. Most products need 24–48 hours before any rain. Read the label. Cover plants below with sheeting to protect them from drips.
6. Clear the gutters and downpipes
After the moss removal and treatment, give the gutters a thorough clean. Blocked gutters are often what accelerated the moss growth in the first place — standing water backs up and keeps the eaves damp.
Check downpipes are running freely by pouring a bucket of water in at the top. If it backs up, there's a blockage somewhere in the pipe run. A drain rod set usually clears it.
7. Fit a zinc or copper strip at the ridge
This is the long-term fix. A strip of zinc or copper fixed under the first row of ridge tiles releases tiny amounts of metal ions every time it rains. Those ions wash down the roof and prevent moss and algae from re-establishing.
To be fair, it doesn't eliminate moss entirely — particularly on very shaded north-facing slopes — but it slows regrowth dramatically and can add years between cleans. Well worth the modest cost of the strip.
8. Plan for a follow-up treatment
A single application of biocide rarely keeps a heavily mossy roof clear for good. Most manufacturers recommend a follow-up treatment after six to eight weeks, once the dead growth has dried and started to break down naturally.
After that, a maintenance spray every two to three years — or annually on north-facing slopes — will keep the problem manageable. Much easier than letting it build up to a full clearance job again.
When to call a handyman
Call Richard if the roof is steep, the moss has got under the tiles, any tiles are cracked or slipped, or if you simply don't fancy working at height. Roof work is one of those jobs that genuinely can go wrong if the access isn't right — a proper set-up and a second pair of eyes makes all the difference.
Worried about your roof?
The Sandwich Handyman covers moss removal, gutter clearing, minor tile repairs, and a range of property maintenance jobs in and around Sandwich, Kent.
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