Can cement dust "bleach" slate, or is there hope? - Brazilian slate slabs now light grey

Patio flagstones (slabs), concrete flags, stone flags including yorkstone and imported flagstones.
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dubster
Posts: 6
Joined: Sun Apr 09, 2017 1:00 pm
Location: Bristol, UK

Post: # 112916Post dubster

Hey guys, I fear the worst, but am hoping maybe some expertise out there will point to an unexpectedly good result.

My wife and I saved and bought a load of Brazilian Slate slabs to have our patio areas done as we were tired of the faded grey rubbish that was there before.

We hired a tradesman to lay them who said he could do exactly what we needed.

Long story short - he turned into a nightmare, cut through our cable/internet line, cemented our upvc step in amongst the slabs, 2 inch thick grout in places, uneven laying of slabs, the list goes on and on.

We're at the point where he's "finished", and the place looks like a bomb site. Cement dust has completely covered the place for around a month, resulting in my elderly neighbour coming out and having a go at him because she's been the only one doing any sweeping for the last month as she was so tired of the cement covering all her stuff too.

So, he "cleans" up and all the slabs are now a really light grey instead of dark grey/blue/black that they were before.
We've told him he isn't getting paid until the slabs are returned to their original colour, but tbh I've had a go at some of the spare slabs and I cant' get them to go back to their original colour, so I doubt with the effort he's putting in they will either. I fear they're now stuck in this horrible light colour.

Sure we won't pay him, but we'd still be out of pocket to the tune of thousands of pounds worth of slabs as we don't want a faded grey patio, that's what we had before.

We're hoping there may be some miracle that can turn them back to their original colour.

I'll include some pictures, and link to all the other pics.
If anyone has any suggestions as to what we might do - we'd be so grateful. Even if it's - use THIS cleaning company etc.

Untouched slab next to how he's left them, we want to get them back to the original colour really. :
Image

Back Garden
Image

Front
Image


Here's the set of photo's I've taken

Cheers all.

S

dig dug dan
Posts: 2504
Joined: Thu Jul 10, 2003 10:20 pm
Location: hemel hempstead,herts. 01442 212315

Post: # 112918Post dig dug dan

There are some very unusual cuts I must say., looks like he started in the wrong place, and ended up with tne cutting we see.
that aside, if its slate paving, a light acid should get the cement off, prior to that, a good pressure washing.
you need to give him a chance to rectify, and dont threaten not to pay him at all, thats not on.
Dan the Crusher Man
01442 212315
www.crusherhire.co.uk
"a satisfied customer? we should have them stuffed!"

dubster
Posts: 6
Joined: Sun Apr 09, 2017 1:00 pm
Location: Bristol, UK

Post: # 112919Post dubster

I've given him the chance to rectify - this is AFTER he's had a go.
Would you be happy with a garden looking like that?
I've given him another week to get to the bottom of it.
I've been decent enough to not complain about his cutting and all the cockups hes made throughout, but Im not paying a guy if the slabs are actually not salvageable.

dig dug dan
Posts: 2504
Joined: Thu Jul 10, 2003 10:20 pm
Location: hemel hempstead,herts. 01442 212315

Post: # 112921Post dig dug dan

it wasnt clear that the pictures you posted showed what they were like AFTER he had cleaned them.
Dan the Crusher Man
01442 212315
www.crusherhire.co.uk
"a satisfied customer? we should have them stuffed!"

dubster
Posts: 6
Joined: Sun Apr 09, 2017 1:00 pm
Location: Bristol, UK

Post: # 112922Post dubster

ah sorry, my mistake. Yeh that's what I've been left with now that he's "finished".

KeburDave
Posts: 48
Joined: Tue Jan 12, 2016 7:09 am
Location: Farnboroughhampshire

Post: # 112924Post KeburDave

I think in a way your lucky its Slate and not a Limestone or Honed Sandstone which would be a lot harder to clean off, in the past we have found a product called Drytreat Eff-erayza works well on cleaning staining off slate, along with a stiff scrubbing brush and a bit of elbow grease you should be fine. Its a lovely slab Brazilian Slate and looks great if laid professionally!!
David Booton

lutonlagerlout
Site Admin
Posts: 15184
Joined: Fri Aug 04, 2006 12:20 am
Location: bedfordshire

Post: # 112935Post lutonlagerlout

it looks massively too high to DPC as well as your other woes
how did you find this *tradesman* Scott?
LLL
"what,you want paying today??"

YOUR TEXT GOES HERE

dubster
Posts: 6
Joined: Sun Apr 09, 2017 1:00 pm
Location: Bristol, UK

Post: # 112936Post dubster

What is DPC?

I got him from MyBuilder. I like the site because it's like ebay in that you can see feedback for their work before hiring. Foolishly this time I trusted someone with zero feedback. They supposedly had 15 years experience and photos of their work. Since hiring, feedback has come in for another job and guess what it is . "this guy ruined our slabs, they're covered in concrete"

So I have myself to blame for wanting to help someone get their their first step on the MyBuilder rung. Won't make the mistake again.

I've spoken to a few cleaning experts now. The response is largely the same - it can be fixed, and needs :

1) A mild Acid bath is applied to "eat away" at the concrete.
2) An Alkaline bath is then applied to "eat away" at the residue of what the acid+concrete has become, and is done before the acid itself has time to damage the slate.
3) A PH balanced bath is then applied to neutralize steps 1 and 2, leaving the slabs as close to their original state as is possible.

Preferably sealing after that.

looking at about 1200 quid plus vat - which Im not paying for his mistake. Thats not gonna go down well!

Tony McC
Site Admin
Posts: 8346
Joined: Mon Jul 05, 2004 7:27 pm
Location: Warrington, People's Republic of South Lancashire
Contact:

Post: # 112944Post Tony McC

DPCs explained.

I'm not sure that such a complicated and chemical-rich cleaning regime is required. Acid will eat away at the cementitious material and then, to "neutralise" you wash off with clean cold water. Not sure why an alkali and then a pH7 wash would then be required.

As long as this really is slate, then a sensible acid dilution (<5%) is very, very unlikely to do any harm, but, as ever, test a small discreet area first.

However, even with a good clean, it's still a crap job that has issues with levels, cutting and, I'd hazard a guess, with the build-up.
Site Agent - Pavingexpert

dubster
Posts: 6
Joined: Sun Apr 09, 2017 1:00 pm
Location: Bristol, UK

Post: # 112951Post dubster

Yeh I tried that on a spare slab already. It stayed light grey.

dubster
Posts: 6
Joined: Sun Apr 09, 2017 1:00 pm
Location: Bristol, UK

Post: # 112952Post dubster

Thanks for the suggestion KeburDave. If it comes to it ill give that product a try.

Dowy
Posts: 1
Joined: Wed Jul 12, 2017 1:29 pm
Location: Isle of Man

Post: # 114054Post Dowy

dubster wrote:Hey guys, I fear the worst, but am hoping maybe some expertise out there will point to an unexpectedly good result.

My wife and I saved and bought a load of Brazilian Slate slabs to have our patio areas done as we were tired of the faded grey rubbish that was there before.

We hired a tradesman to lay them who said he could do exactly what we needed.

Long story short - he turned into a nightmare, cut through our cable/internet line, cemented our upvc step in amongst the slabs, 2 inch thick grout in places, uneven laying of slabs, the list goes on and on.

We're at the point where he's "finished", and the place looks like a bomb site. Cement dust has completely covered the place for around a month, resulting in my elderly neighbour coming out and having a go at him because she's been the only one doing any sweeping for the last month as she was so tired of the cement covering all her stuff too.

So, he "cleans" up and all the slabs are now a really light grey instead of dark grey/blue/black that they were before.
We've told him he isn't getting paid until the slabs are returned to their original colour, but tbh I've had a go at some of the spare slabs and I cant' get them to go back to their original colour, so I doubt with the effort he's putting in they will either. I fear they're now stuck in this horrible light colour.

Sure we won't pay him, but we'd still be out of pocket to the tune of thousands of pounds worth of slabs as we don't want a faded grey patio, that's what we had before.

We're hoping there may be some miracle that can turn them back to their original colour.

I'll include some pictures, and link to all the other pics.
If anyone has any suggestions as to what we might do - we'd be so grateful. Even if it's - use THIS cleaning company etc.

Untouched slab next to how he's left them, we want to get them back to the original colour really. :
Image

Back Garden
Image

Front
Image


Here's the set of photo's I've taken

Cheers all.

S
Dubster,

Did you get this issue sorted?

if so how and what were your results. i'm having a similar issue after having a wall rendered next to a patio and the guy washed his dropped render across the top. it was a cement and lime mix and has turned my tiles from anthracite to grey / white.

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