Apologies for not making it clear.
Yes, they should all match to pale grey (arctic granite glacier), which they did when it was dry.
Once wet the flags turns very dark in colour, to a charcoal grey from pale grey. This applies equally to all of the supplied flags by Gibbs & Dandy. However, flags supplied by Marshalls retains its true colour regardless of the weather conditions.
Just for clarity when you say marshalls, I am assuming that you mean stone market. Apologies if I am asking stupid questions but you referred to stonemarket in your OP.
I'm assuming though that the stuff supplied by Gibbs and dandy is also a marshalls/stonemarket product?
Like Luton says you need to seal the stuff that's not been sealed. I would advise speaking to marshalls/stonemarket and sourcing the same sealant that's been used already. In theory that should solve the issue
As far as I know, there's been no major changes in the so-called Arctic Granite over these years, but, as it is a natural stone, the nature of the rock itself may be petrographically slightly different, as it will come from a different part of the quarry or even a different quarry.
As LLL suggested, it would seem that the unsealed flags need to be sealed *with the same sealant* to match those already treated, and so you would need Marshalls/Stonemarket to reveal just what they use (good luck with that!)
However, the pre-sealed flags were typically dipped/sprayed, so ALL faces and edges were sealed. Retrospectively applying a sealant, even the same sealant, to just the upper face will NOT render them a match for the previous flags, as moisture will still be able to penetrate the granite from the edges and the bed.
My best guess is that the unsealed flags will have to be lifted and replaced with sealed units, and from what infomation we have to fdate, it really isn't clear who is at fault and therefore liable for the costs.
Further developments with regard to our complaint is that Stonemarket are now suggesting that the sealed slabs are at fault i.e those purchased from Marshalls because apparently the sealed slabs were discontinued two years ago! We are struggling to see the logic of this.
We have spent in excess of £5000 alone on slabs, not to mention sub-base materials and installation costs and yet we have what turned out to be a very disappointing result.
