SmartSeal Green Clear Pro - 25L - Concentrated Biocide & Green Growth Remover. Spray and Leave Roof Tile Cleaner, Patio Cleaner & Algae Remover. For Use on Concrete, Wood, Decking & Stone

This works, you can use it above 0 degrees C, Moss clear you need to use above 8 deg C so you can get this on your green stuff earlier on the year and it will work. I sprayed this on our render, decking and patio, within 24 hours the algae had started to clear, the rest of it was gone within a week and it seemed to continue workign beyond that as these things continued to clear.

I applied this to a very mossy garage roof last September, having bought it a few weeks before. I followed the instructions and waited until the temperature was below (i think I recall correctly, but read the instructions yourself) 20 degrees celsius. We bought the house 3 years ago and I suspect there was 20+ years of moss and lichen on the garage roof. It is now the following April and until about three weeks ago, I thought that the product had been useless: no loss of moss/lichen and the roof looked just as awful. However, my ex-farmer friend visited and when I told him SmartSeal had not worked, he said "yes it has!". He pointed out that it was dry and dead, but still affixed to the roof. All it needed was a scrape with a stiff brush, or, I'm hoping, the drying effects of the sun plus some wind might remove it entirely (it has been an exceptionally wet winter in the UK).

Astonishingly effective biocide. I have an outside wall that has bushes close to it, and which was covered with an unsightly green growth. I used one application and had low expectations of its effectiveness. But two weeks later the growth was gone, the wall was back to white, and a year on the growth hasn't returned.

Had my parents roof cleaned of all the moss and then applied this sealant. It went on very easy using a large brush. Doesn’t stain the roof tiles and only time will tell if if stops moss returning - but this was recommended by a roofer so fingers crossed.

Kills the moss quite quickly but requires a second application a few weeks later. I now use vinegar bought in 5L containers. Also needs 2 applications at a fraction of the price,

Does what it says. Twin pack great value

Very good

Great