I commissioned a gardener to lay a new patio for us. I wanted varied sizes and very dark grey.
The slabs were delivered by Travis Perkins, along with sand etc.
Patio laid starting last Monday 20th.
On Thursday evening I checked as I started to worry about what was being laid. It turns out they are limestone not sandstone as the heading says on the TP site. (screen shots in photos)
On Friday the guys arrived to finish last few slabs, grout and clean. I asked what they were going to use to clean - they said brick/patio cleaner. I said NO! So they have not cleaned the patio other than with water.
When complete the patio looked good - still wet!
However now after the rain on Sunday and dried out it looks as per the photos.
I am assuming some of this is effervescence but also cement dust? They used a wash/sweep in grout that was sort of blue/black and is now very dark grey with black crystals in it.
I've looked through lots of posts on here but I'm a bit confused. I have some off cuts to test cleaners on. What should I do? Lithofin, Grimex, something else? Or is it ruined and needs removing again? Not sure how that will go down with gardener! (I asked and he'd used sandstone lots of times before but not this dark grey )
What have they used for the jointing? That looks like jointing residue....but you say it was a dark proprietary product, which suggests resin-based, wich should not stain like that.
It could be cement from the bedding - if they are untidy in their work, it's easy to contaminate the surface with bedding mix.
Although there could be an element of efflorescence, it's unlikely so soon after installation and at this time of year when temperatures are warmer.
The Carbon Black sandstone is very fickle when it comes to clkeaners. The ones based on hydrochloric acid are best avoided as the results are just too unpredictable. Phosphotic may be safe, but as you know,m you need to test offcuts or one in a discreet corner....but be aware that because of the natural variation of the stone, just because an offcut doesn't reach adversely to a cleaner, that doesn't mean it's safe to splosh it about everywhere.
As a first move, I'd try one of the phosphoric acid cleaners and se how it goes but there's a good chance that the only real fix is to have it all replaced.
Yes I think mostly cement and some dust from cutting - the grout was 'washed' in and has not marked the last laid slabs so I don't think that is the culprit. There are splash marks in places and some places look like they have tried to mop up the dropped cement.
They did ask the retailer before using this sealer if it was ok on Limestone and were told yes.
They have said they will get a cleaner. I will make sure it it tested on an off cut and then on a patch that is not seen before they 'splash it all over'.
I hope it can be saved - I'm not sure I can face having to have the patio re done for a third time! (I had already had someone try to re lay the existing patio 3 years ago which was also a disaster with water pipes cut and then they walked off site halfway thought) My neighbours also work nights and I get grief every time I have anything done to the house.
looks like they were just a bit untidy with their laying technique
need a bucket of clean water and a brush at hand when laying any flags
I am guessing its weatherpoint ?
LLL
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