Roof soft wash: clean without the pressure
Soft washing cleans a roof with a cleaning solution at low pressure instead of a high-pressure jet. It kills moss, lichen and algae at the root and lets them rinse away, so the tile surface is left intact.
- Low pressure, no blasting
- Biocide treatment
- Free, no-obligation quote
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Why pressure washers stay off the roof
A high-pressure jet strong enough to blast moss off a tile is strong enough to take the tile’s surface with it. On concrete that leaves a rougher, more porous tile that moss grips even better next time. On clay and old tiles it can erode them. On slate it can lift slates from their nails. And it can force water up under the tile laps.
A soft wash does the work chemically, not by force. The solution does the cleaning, low pressure carries it, and the roof is left as it was, just clean.
Read the full comparison
Drag to compare. Slate, before and after a soft wash.
Soft wash vs pressure wash
| Soft wash | Pressure wash | |
|---|---|---|
| Tile surface | Left intact | Can be stripped |
| Water under tiles | Very little risk | Can be forced in |
| Roots and spores | Killed | Often left behind |
| Slate and ridge tiles | Undisturbed | Can be lifted or cracked |
| Mess | Contained | Sprayed over walls and windows |
Roof soft wash: questions answered
Do you soft wash garages, porches and outbuildings?
Yes. Garage roofs, porch roofs, bay roofs and tiled outbuildings are cleaned the same way as the main roof, and are often included in the same visit.
These low roofs are usually the first to go green, because they sit in the shade of the house and catch drips from the roof above. Mention them when you ask for a quote.
How does a soft wash actually clean the roof?
The solution does the cleaning. It soaks into moss, lichen and algae and kills them, including the roots and spores you can’t see, and low pressure carries it onto the roof and rinses the loosened growth away.
That’s the opposite of a pressure wash, where force does the cleaning and the chemistry is an afterthought. Because the growth is killed rather than knocked off, it is slower to come back.
What pressure does a soft wash use?
Low pressure, roughly what you’d expect from a garden hose rather than a jet washer. It’s enough to apply the solution and rinse, not enough to strip a tile or lift a slate.
The aim is that the roof surface, the mortar and the fixings are left exactly as they were, only clean.
Is soft washing suitable for every roof?
For tiled and slate roofs, yes: concrete, clay, natural slate and man-made slate. Very old or listed roofs get the gentlest, treatment-led version of it.
Flat roofs and roofs needing repair are different jobs. If yours is one, we’ll tell you honestly whether we can help or whether it needs a roofer first.
Will I see a difference straight away?
Yes. Moss and algae come off on the day. Lichen is killed on the day but fades and washes away with the rain over the following weeks and months.
That second stage is normal, and it’s why a soft-washed roof often keeps looking better for a while after we’ve left. Scraping lichen off to finish on the day would damage the tiles.
Can soft washing be used on render and walls?
Soft washing is used on many outside surfaces, but this site is about roofs. If your render or walls are streaked as well, mention it when you ask for a quote and we’ll tell you what we can help with.
Algae streaks on walls below a roof often come from the same source: water running off a mossy roof or overflowing gutters.
Four steps, one visit
Free quote
Send your postcode and a photo, or call. We price the roof and tell you honestly if it doesn’t need doing yet.
Hand clear
Thick moss is lifted off by hand first, so we never need high pressure to shift it.
Soft wash
A cleaning solution at low pressure kills and lifts algae, lichen and moss roots without blasting the tile surface.
Biocide and tidy
A biocide finish keeps working for months. Debris is cleared from the gutters and the ground before we go.
Questions people ask
What is a roof soft wash?
A way of cleaning a roof with a cleaning solution at low pressure instead of a high-pressure jet. The solution kills growth and it rinses away.
Is soft washing safe for clay tiles?
Yes. It’s the method clay tiles need, because they’re softer than concrete and easily damaged by pressure.
Is it safe for my garden and pets?
We’ll talk you through what we do around plants, ponds and pets when we quote, and keep pets indoors while we work.
Why does the roof keep improving after the clean?
The solution and the biocide keep working. Dead growth, especially lichen, loosens and washes off with the rain over the following weeks and months.
Find out what your roof needs
Send us your postcode and a photo if you have one. Free quote, honest advice, no pushy upsell.