[*Derek*]

Can i get an opinion on this.

Surface has been powerwashed not by us. Poor results.

I was thinking of using either Hypo or high alkaline cleaner, Aggitation and either vac or powerwash off.


Any other suggestions for me?

[*Derek*]

more pictures

[chris scott]

Looks like very badly laid sandstone not limestone . With (hard to tell from pictures but possible) residual sealer and black spot. Image 1
Leave it alone...unless the customer likes to pay.

[BDCS]

Looks like they have had brick acid on it - I too agree there are easier ways of earning a crust  I would wet blast a section to see what happens and go from there

[drive surgeon]

Isn't that York stone. It's not limestone

[Kev Martin]

Clean it as follows

Pre wet
Apply high alkaline scrub in with a manual rotary scrubber
Apply honing powder and scrub so the surface ends up with an overall even appearance
Then rinse
wet vac
rinse and vac again
then seal

Kev Martin
Tiling Logistics Ltd

[chris scott]

Clean it as follows

Pre wet
Apply high alkaline scrub in with a manual rotary scrubber
Apply honing powder and scrub so the surface ends up with an overall even appearance
Then rinse
wet vac
rinse and vac again
then seal

Kev Martin
Tiling Logistics Ltd

Did you get the gay clay?

[Kenny83]

Looks like it's been layed on concrete just spotted around to hold the slabs in place, as opposed to being layed on a full solid bed, this is usually what the after effects are

[*Derek*]

More feedback.

I did a test area with high alkaline solution and test patch came out well but not all black spots came off. I don't think surface was sealed before.

The previous company who cleaned it damaged all the grout. It was perfect before that and never got black spots either.

[Kev Martin]

Add honing  powder

Kev Martin
Tiling Logistics Ltd

[chris scott]

More feedback.

I did a test area with high alkaline solution and test patch came out well but not all black spots came off. I don't think surface was sealed before.

The previous company who cleaned it damaged all the grout. It was perfect before that and never got black spots either.

Be careful ...I think the customer is telling you porkies. The pointing looks like it has failed "naturally" and most (not maintained) sandstone has lichen growing on it.

[*Derek*]

You might be right Chris!

Thanks Kevin, We'll give it a go!

[Roger Oakley]

Badly laid & badly maintained Sandstone, Charge accordingly to clean & seal this.