Removing roof moss yourself?
By the Toiture Wash team · Updated on 20 October 2026 · 4 min read
Short answer. You can remove moss yourself from a small, low roof, from a stable ladder, with an anti-moss product sold for this use and following its label. Above ground-floor level, the real danger is not the product but the fall: a mossy roof is slippery. Bleach should be avoided altogether, and the pressure washer needs a steady hand so as not to damage the tiles.
What you can do yourself without risk
- Look at your roof from the street and the garden at the end of winter, with binoculars if need be.
- Clean the ground-floor gutters from a stable ladder, by hand, wearing gloves.
- Trim the branches that overhang the roof and shade it.
- Treat a low outbuilding, a garden shed or a canopy that you can reach without walking on the roof.
Shop-bought moss killers
DIY shops sell anti-moss products for roofs, ready to use or to dilute. They are applied with a sprayer on a dry roof and kill the moss, which the rain then washes away in a few weeks or months. Three rules:
- Choose a product sold for this use, and read its label: dose, weather conditions, personal protection, time before rain. An anti-moss product is a biocide: in Belgium, it must be authorised and carry an authorisation number on its label, which you can check on biocide.be. The most dangerous products are reserved for professionals.
- Protect the tank: disconnect the downpipes that feed it. See Roof moss removal and rainwater tank.
- Protect plants, animals and fish: a product that kills moss is not harmless to the rest of the garden.
There is no "best product" in absolute terms: it depends on the surface, the moss and what the water running off the roof is used for.
Bleach: no
It is often recommended on online forums. It whitens the moss, but it is corrosive to materials, it damages zinc flashings and seals, and it ends up in the gutters, the garden and sometimes the tank. Wallonia, incidentally, bans salt, vinegar and bleach as weedkillers, because they acidify the soil or contaminate groundwater.
Home-made mixtures (vinegar, bicarbonate of soda, black soap) also circulate: their effect on a whole roof is limited and they call for the same precautions at height.
The garden pressure washer
A high-pressure washer removes moss, but it poses three problems on a roof:
- the position: you have to work on the roof or at the top of a ladder, with a machine that kicks back with every jet;
- the setting: too close or too strong, the jet wears a porous tile, and aimed upwards, it sends water under the tiles;
- the splashes: water laden with moss on facades, windows and at the neighbours'.
The manufacturers say the same: Wienerberger, which makes Koramic tiles, advises avoiding the high-pressure washer and aggressive cleaners, and preferring a soft brush or a special low-pressure roof cleaner; Eternit points out that strong pressure can cause leaks on its corrugated sheets. Comparison of methods: Which moss removal method for your roof?
The real risk: falling
A roof covered in moss is slippery, even more so when wet. A badly placed ladder, a foot on a tile that breaks, a gutter that gives way: a fall from height is the major risk of any work on a roof. Never climb up alone, never onto a wet roof, never without a harness above ground-floor level.
Before you start: asbestos
If your roof is made of artificial slates or corrugated sheets laid before the ban on asbestos, do not clean, scrape or brush it until you know whether it contains asbestos. Does my roof contain asbestos?
When to call a professional
- the roof is above ground-floor level;
- the moss is thick or the lichens are established;
- you want a treatment after the cleaning, water repellent or algicide;
- the roof carries solar panels;
- you have a tank and do not know which downpipes feed it.
Frequently asked questions
Can you remove roof moss with a Kärcher?
Technically yes, but the risk of falling and the setting of the jet make high pressure a job for a professional beyond a low outbuilding.
How much does a do-it-yourself moss removal cost?
The price of the product and the equipment, plus your time. Compare it with the price of a professional for your roof: the estimator gives it to you in one minute.
Is the anti-moss product enough?
It kills the moss, but does not remove the deposits or the embedded lichens, and you have to wait months for a visible result.
Sources
Pages consulted on 2 October 2026:
- Biocides: what you need to know before using them (FPS Public Health) (in English; French and Dutch versions on the same site).
- Main uses of biocides in the Green Sectors (PreventAgri) (in French).
- Salt, vinegar or bleach: NOT WEEDKILLERS! (L'Environnement en Wallonie) (in French).
- Tips for maintaining a roof (Wienerberger) (in French).
- Moss on the roof (Eternit) (in French).