In short, I used a landscaper/gardener to completely renovate my small garden. I think the patio has been botched and haven't fully paid for the job yet. I have the option of asking them to re-do the whole job or asking them to re-lay certain slabs and use chemicals to improve the staining that they've left.
The first problem came after they cleaned the slabs with an acid based patio cleaner shortly after laying the patio. I notice from this site that this should NEVER be done with this stone
Here is what the stone looked like before they applied patio cleaner:
And after the patio cleaner was applied:
The landscaper initially told me that some amount of rusting should be expected with this type of stone naturally....The landscaper eventually seemed to see my issue and suggested that Lithofin Rust-Ex/Bero would fix this. At my own expense, I purchased Bero and applied it exactly as the instructions suggested. This got rid of a lot of the rusting. BUT a new issue was left - a high degree of 'blotchiness'. Hard to describe this odd effect but these pictures highlight this issue:
You can see it looks nothing like it should do with a high degree if contrast between the dark and light colours on the slabs. The landscaper again was a bit slippery about this saying that the Bero chemicals just accelerated what would happen naturally with this type of stone.....
I called up London Stone (I thought this was where he got the slabs from as he sent me a link to their stock when designing the garden - it turns out that they haven't had an order from him since 2013 though). Having sent pictures to them, they suggested that he might've dot and dabbed the slabs instead of laying with a full bed. It was at this point I started to question the integrity of the rest of the job - at least 5 slabs make a crunching noise as you walk over them and in a couple of places, mortar has completely come out of the joints. So there seems to be a few slabs that are loose to some degree.
I started reading this site more and realised the clear problems around dot and dab. I also read about how the patio should have a 1:60 fall incorporated at this point. I can't check for the former (the landscaper insists they don't dot and dab slabs) but for the fall, I have measured all over with a 1.2m spirit level and it seems flat as a pancake! There should be approx. 7cm of fall from the start to the end and I cannot find that. There is one particular area where water pools and sits - conveniently, this is the only area where moss is growing on the jointing.
This week, London Stone kindly sent someone over to have a look - he was a specialist in chemical treatment, not in laying so couldn't really offer advice on the way it's been laid. He thinks a product called Akemi might get rid of the blotchiness. But I would still be left with the loose slabs, loose jointing and lack of a suitable fall on the patio. The landscaper has at least admitted that the loose slabs need to be taken up and re-laid.
So I wanted to see what the experts on here would suggest - would you live with it and try a dose of Akemi, and let him re-lay the loose slabs OR would you ask for it to be ripped up and done again, properly (i.e. full bed, with a 1:60 fall and NO ACID CLEANER!!!)? Another option if I seriously doubt the competency of the landscaper would be to hold back the remaining payment and try to find someone else to re-do the job. Would be very helpful to see what people here think as this seems like the best place I'm going to get an educated view from.
Thanks.