Using bleach on slabs

[shifty_uk]

My patio slabs are covered in some dreadful mould which doesn't seem to be coming off fully with the pressure washer/slab cleaner.

I've read bleach does the trick for this stuff but wondered how safe it was and if/how quickly it evaporates as I have dogs?

I'm going away next weekend so they'll be staying overnight elsewhere; If I did the garden on Thursday night, do you reckon it would be safe for them to return home on the Sunday?

 

[gort]

Should be fine. Just give it a rinse after the mould goes.
I bleached some rocks from my aquarium ages ago to get rid of algae stains. Left them in a mild bleach solution in a bucket for a day and then rinsed them off (added de-chlorinator to be sure) and allowed them to dry.
Fish were fine and imagine they are more sensitive than your dog.

 

[DXP55]

Don't make the solution too strong - I think it took surface off my slabs - I now use bucket of warm water and cup of bleach - use soft broom and brush over the slabs then really brush it to suds - leave till dry them hose off - it does a good job but I am sure I over did it.

Need to do mine again soon.

 

[DanTheMan]

Soda crystals! I've never found anything that works as well as them for paving, just mix a bucket of solution and pour over and scrub.

Plus, that last time I bleached the path, I turned my trainers yellow.

 

[Usel]

I have used chlorine granules many times to clean slabs. I usually do it on a wet day whilst still raining.
Sprinkle a few granules, half a cup over 25m2, all over the slabs and leave 2 mins to start to melt. Then with a broom brush all over, you just need to move the water all over you are not needing to scrub. Leave for 5mins and do the same again, this times you should notice the green or black starting to come off.
Leave another 10mins and then rinse off throughly with a hose.
Slabs should brand new and will be fine for the dogs that day/evening to walk on.

 

[Cookeh]

Bleach neat, 2 dogs, no issues. Just rinse it well and let patio air dry. We put bleach straight on from the bottle, brush it in, then pressure wash off. Works well.