[serj shergill]

Hi folks any advise on how i can clean this patio? It has a kind of white staining. Sorry about the quality of pics

[Smudger]

Sorry, did you take these pictures in secret with a toy camera, I know I need an eye operation but really ? What on earth is that a picture of ?

Darran

[Rob@Blast off]

Looks like a solar panel to me but I'm on a phone with a small screen

[Matt.]

Looks like the picture is on the tv

[Smurf]

Whatever it is it looks damned to me.

Might help if you knew what the slab was and how the stains came about in the first place.

[serj shergill]

It's what the customer sent, I know there poor quality.  He has 200sqm of concrete flag which have a rough black surface. The stains are mortar residue from shoes and have seemed to settled in the rough surface. The customer does not want to use a acid wash as he feels it will damage the stone.

It's over 150 mile round trip and don't want to be quoting on  something that is beyond my limited knowledge.

I was wondering if a high pressure wash would do or does it need hot water treatment?

Thanks

[samson]

If I were you I would quote a decent price to start, and factor in the travelling and anything that could go wrong !
If they value your workmanship, they will go for it, and if not you are better off walking away 

[Kev Martin]

It's what the customer sent, I know there poor quality.  He has 200sqm of concrete flag which have a rough black surface. The stains are mortar residue from shoes and have seemed to settled in the rough surface. The customer does not want to use a acid wash as he feels it will damage the stone.

It's over 150 mile round trip and don't want to be quoting on  something that is beyond my limited knowledge.

I was wondering if a high pressure wash would do or does it need hot water treatment?

Thanks

If it is grout haze and residue no amount of pressure washing hot or cold will get it out.  Get them to send you some better photos with overall scenes and close ups!  Which idiot customer expects a quote over the phone for a patio 200 M2 with a couple of crappy pictures.  If the haze is heavy it would be around £5K from me plus VAT  If it is light it would be around £3500-£4000 + VAT.   You will need

2 x SIC Brushes 80 Grit
Mono Rotary Scrubber
Wet Vacuum
6-8 Gallons of Acidic Cleaner Heavy Duty
2 Gallons of pH Neutral Cleaner
5KG Each of Honing Powder 220 Grit & 400 Grit
2 Days to do it / 3 Days if they want sealing + Price of the Sealer
Pads, Applicators, Masking Materials etc etc

Then are you going to commute 300 mile round trip daily or stay in accommodation?
300 Miles Fuel possibly per day???
Food Subsistence???

[serj shergill]

The staining is only on a few blocks,  but want the rest of the patio cleaned as well. .

thanks for the advice

[chris scott]

Black concrete ?  Acidic cleaner?

[Kev Martin]

Black concrete ?  Acidic cleaner?

Chris we don't actually know for sure it is black concrete but nevertheless even if it is concrete,  or limestone etc  for that matter the acid will remove the cementitious haze provided  it is not too thick this in turn (I agree with your thinking and you are correct) will etch the stone but then the Honing powder will cut a few microns back off the stone and give it an overall even aesthetic appearance and then the finer grit honing powder will close the stone back down again.  If you like you are being cruel to be kind

[chris scott]

Never heard of black concrete…more likely black limestone-acidic cleaner?