Hoping you can help - and apologies if this is in totally the wrong place - I just had to Google what a 'flagstone patio' was so that's around the level of expertise I have here!
We recently renovated our garden in North London and I fell in love with Rainbow Sandstone, which we had laid between the house and garden. But three months later it looks like the images here ???
So from looking online I think I need to jet ash the algae away (I thought it was moss...again, I am clearly not an outdoors person and this is all a bit new to me with my first house!) and then use a cleaner and sealer? But everywhere I look there are different suggestions and tools so I was just after some advice on how I fix this as I feel like I made a mistake with the sandstone and not looking into it first. The guys who laid it said it would easy care and I could just put it down and leave it - being a 30 year old girl who travels alot with work that sounded ideal, but I really should have looked into it more. And definitely didn't think it would look like this after just a few months rather than years...
Anything you can suggest would be amazing and a huge help before I just make this all worse!
Jaysus! That's awful. Not only is your installer a bare-faced liar by claiming Rainbow Sandstone is "easy care", he's a totally incompetent cowboy who has not even been able to lay the paving badly....he's laid it horrendously. Easily the wrost job I've seen this year (I know: it's only February, but still...!)
There is no rescus for that mess. The pointing is all over the place; there are crossed joints galore, the drainage looks highy suspect; the cuting is shocking - there's absolutely nothing good to say about it. I'm sorry!
Jet washing will NOT make this a good pavement. It will probably shift the algae, but Rainbow is such a soft and crap stone that there is a real risk the power of the water jet will damage it, and I don't hold out much hope for that comedy pointing!
To spend good money on a sealant for that utter shite would be a travesty. Rainbow absolutely guzzles sealant, so you'd need at least two coats, and the coverage is shockingly poor. To get a competent tradesperson to undertake a sealing job on that stone, using a good quality sealant will cost you somewhere around 15 to 20 quid per square metre, possibly even more as you are in that London.
Have you any recourse against this buffoon? If you took the uselss git to court, he'd lose without a doubt, but could you get any money back?
Where do you find people as bad as this? Asleep in a skip outside Wetherspoons on a Sunday morning?
Unfortunately Rainbow sandstone is one of the most soft, porous stones around, we ran some sealing tests on it recently and it is like a sponge!!!!
It goes green very quickly but it shouldn't look like this after only 3 months which makes me think that there might not be proper run off, fall on the paving, so water is sitting and just seeping into the paving.
This Sandstone in my opinion is just not "fit for purpose" unless it has been sealed with a good quality impregnating sealer.
The paving needs to be properly cleaned in late Spring when it is reasonably mild and dry. I would initially use a product like a moss and algae cleaner like Algex from lithofin first then if it still needs a clean an outside cleaner like Oxy cleanser might do the trick.
I would then seal the paving using an impregnating sealer like Drytreat Stainproof but this is quite an expensive product and you would need at least 3 coats on the Rainbow as its so porous.
But check the falls first as if there is not adequate falls or drainage you don't want the patio becoming a paddling pool once the sealant has been applied!!!!
Cheers
Dave
You would be better off getting the paving cleaned with a low speed rotary, less chance of damage on such a soft stone, plus the pointing!!
To clean & seal you would be looking in the region of £20-£25 + vat per square metre, as said that stone is going to drink the sealer.
