Patio black spot treatments

orangecrush

Hello moneysavers,

tl;dr: have you successfully removed black spots from your patio; if yes how? And did it kill your plants/ grass? 

I have been researching how to restore our very grubby 30 year old patio, long neglected by the last owners of this house. I have pressure washed it, and it has come up quite nice but the removal of decades of dirt and algae has highlighted decades of black spot.

I started researching black spot treatment, and there seems to be a variety of products at different price ranges and with varying instructions. E.g. one says it is safe for plants and grass, but another says exactly the opposite… the thing is though, they’re both essentially just bleach (sodium hypochlorite). 

I’m interested to hear others experiences of black spot treatment - did the product you used work well? Did it kill the grass around your patio? Did the stone look significantly better? Any other adverse effects? 

The other thing that’s crossed my mind is, given these treatments all seem to be just bleach, could I buy cheap thin bleach and just spray that onto the patio stones?

The garden is all getting re-done next year so I’m not precious about it, I would just like it to look a bit less scruffy! 

Thank you! 

pmartin86

You got any pictures? Black spots could be quite a range of things. 

Anything bleach based will kill plants around it, so you need to try and keep it contained and not "splash it about" or run off into the lawn. That being said, id probably get some "normal" bleach in an old spray bottle and dilute it a little so it flows and start spraying, see what happens, if you're planning to replace anyway, doesnt really matter.

koalakoala

Wet and forget was the only thing that worked on mine. I tried neat bleach several times, didn’t work

Ant555

This product worked an absolute treat for me on my patio.  I must have had the exact black spots that the product is designed to combat.

https://www.prokleen.co.uk/pro-kleen-ultimate-black-spot-destroyer

My patio is close to the house and water drains directly into the main drain so it was easy for me to keep it away from the grass when flushing afterwards.

MouldyOldDough

We have quite the opposite "WHITE SPOT" all over our patio - presumably from bird droppings ?

orangecrush

pmartin86 said:

You got any pictures? Black spots could be quite a range of things. 

Anything bleach based will kill plants around it, so you need to try and keep it contained and not "splash it about" or run off into the lawn. That being said, id probably get some "normal" bleach in an old spray bottle and dilute it a little so it flows and start spraying, see what happens, if you're planning to replace anyway, doesnt really matter.

Thanks! I’ve attached a few photos. It is in a pretty sorry state. Lichen I don’t mind so much, but the black spots are pretty densely distributed in some areas.

orangecrush

Ant555 said:

This product worked an absolute treat for me on my patio.  I must have had the exact black spots that the product is designed to combat.

https://www.prokleen.co.uk/pro-kleen-ultimate-black-spot-destroyer

My patio is close to the house and water drains directly into the main drain so it was easy for me to keep it away from the grass when flushing afterwards.

This is one of the products that I was thinking of buying, but it is essentially just bleach. It says it is harmful to plants and will kill grass - ok, that’s fine. But what confuses me is there’s another (more expensive) product that is also bleach based that says it won’t kill grass or plants. 

If they’re both bleach I can’t see why one would be safe and another not?! In which case I might just go for this cheaper one 😁

thanks for your input! 

Emmia

If you're replacing it anyway I'd probably just leave it, the slabs look fine to me, just need recement/sanding in the gaps.

orangecrush

Emmia said:

If you're replacing it anyway I'd probably just leave it, the slabs look fine to me, just need recement/sanding in the gaps.

Yeah the récemment definitely on the to-do list. I’d just like it to look a bit nicer for the summer y’know? I'm impatient to get our garden redone but the guy we want isn’t free til next spring, so I want to do something in the meantime. 

robinwales

Gravel. No need to clean, just rake it over. I use hypochlorite on my front drive, but it is ghastly stuff to handle, and you need lots of protective gear, especially goggles, and if you have kids or pets around it may not be the best idea. Bleach will kill or damage plants and grass. There are other products available, but I have found they don't work all that well. Be careful!

orangecrush

Sometimes I think bleach gets a bad rep - it is nasty when concentrated for sure. But diluted it is used for sterilising baby bottles, and degrades to salt and water. I’m not saying I wouldn’t ve super careful, I have kids and pets, but I was just looking at the Wet and Forget stuff and it’s even more noxious than chlorine bleach. 

Maybe I should just leave it… Paint the shed to distract me from the scruffy patio!