Lichens on sandstone patio paving

No idea how to get the black spots off, but Battimoss may help with preventing them breeding lol

As for using any stone cleaners be very wary, if there is any lime or shell fragments in your sandstone, which would not be unusual, patio cleaners which are often acidic.

These could damage the surface by slowly eroding the lime fragments, which in sandstones can often be found to be "cementing" the sand grains together. It depends entirely on the origin and composition of your sandstone.

Lichens are wonderful! Just try looking at them through a hand lens. They are a normal part of the natural environment. It seems wrong to me to remove them. Given time it will give your patio a much more natural appearance that will blend more easily with the environment.

Patios need patinas!

Patio Magic is what you want. Shop around for best price. It's a doddle to use and it works. Pour it over the patio when you have diluted it and go and put the kettle on, make a cuppa. That's it. Job done.

Hi shysal,
thank you for your response, we have the patio attachment which is good for the top filth but it makes no difference to the lychen.

My concern is it will take over the whole paving eventually and when I think how beautiful it was when first laid I could weep.

From paving expert I found a chemical which may help called Calcium hypochlorite so I'll give it a try if I can find a company who sell it.

Like you I tried thick bleach, but it is a faff as the area has to be protected from cats walking over it, so did a patch at a time.It made little difference, I find once the patio starts to weather again I bardly notice them.
A good buy last year was a patio cleaning attachment for my Karcher pressure washer, it works a treat without the normal splash, and is as quick as hoovering. Works on walls and decking too.