Pressure washing marks on limestone

Patio flagstones (slabs), concrete flags, stone flags including yorkstone and imported flagstones.
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Jock Stewart
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Post: # 36361Post Jock Stewart

Hi all, have read loads and learned lots so thanks to all for an excellent site. I have recently started a driveway cleaning business and am happy that I can provide a high quality service to my customers. And then this one comes along! Very bad marking to limestone slabs caused by a pressure washer and then being sealed in with Eureco Systems PAVEGARD product. This was done by the installer about a year ago. The surface has been recently contaminated with spots of goo from cavity wall installation. Pictures available Customer is a pleasure to deal with and I would like to give him best advice. Any help gratefully received
I'm a man you don't meet everyday!

Kevin Magill
Mission 251
Professional Hard Surface Cleaning
www.mission251.co.uk

Tony McC
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Post: # 36363Post Tony McC

Get some photies - I can't imagine how a pressure washer can mark a limestone, unless it's an exceptionally powerful water jet and poor quality limestone!
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Jock Stewart
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Post: # 36368Post Jock Stewart

Hi Tony, I have the photos and can email them but don't know how to upload to the forum!
I'm a man you don't meet everyday!

Kevin Magill
Mission 251
Professional Hard Surface Cleaning
www.mission251.co.uk

Tony McC
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Post: # 36369Post Tony McC

Email them to me and I'll upload them for you.
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Tony McC
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Post: # 36375Post Tony McC

The photies....

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....those marks are not stains, they are irrefutable proof of incompetence. They are the 'trail' left by a high pressure jet that has been waved about willy-nilly across the paving by an eejit with no real systematic approach to cleaning the flags. This is why a rotary cleaner is *so* much better than a lance. They clean the whole surface, not just the odd bit.

If a lance must be used, then the water jet needs to be directed at the paving at a shallow angle and in a systematic method that ensures every single square millimetre of the pavement surface is cleaned, not just squirted.

If you re-clean the surface using a rotary cleaner, those marks should simply disappear.
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Jock Stewart
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Post: # 36381Post Jock Stewart

Thanks Tony. I use a Nilfisk Alto Power Scrub (500mm rotary) so have advised the customer I can do a good deep clean, but I have been told that the surface has been sealed with the PAVEGARD over the marks seen on the photos. I believe I should wait and see what the cleaning achieves before I commit to a new sealant. If it does not come up to standard, is there a way to remove the Pavegard? My recent past involved high tech industrial abrasives but I am not ready to shave off the top layer with a floor sander, rotary or not!
I'm a man you don't meet everyday!

Kevin Magill
Mission 251
Professional Hard Surface Cleaning
www.mission251.co.uk

Amogen
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Post: # 36384Post Amogen

Tony McC wrote:If you re-clean the surface using a rotary cleaner, those marks should simply disappear.
As the paving has previously been cleaned and the sealed, the sealant would need to be removed prior to cleaning with a rotary system.

This is a messy and nasty job. I know lads in the PIC trade that have to remove acrylic seal and they hate it!!

You will have to remove 100% of the existing sealant to achive anything like a good result.
Regards,

Andy Willcock
Amogen Drive, Decking & Patio Cleaners
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RAPressureWashing
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Post: # 36393Post RAPressureWashing

Jock,
You say the installer did this? he should be shot.
As stated 100% strip of the old sealer then you can start to try and repair the damage. I feel washing alone won't get rid the marks, I might be wrong but thats just my opinion.
Roger Oakley BDA(Europe)Member 2006
R&A Pressure Washing Services Ltd
info@rapressurewashing.co.uk
www.rapressurewashing.co.uk

Tony McC
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Post: # 36406Post Tony McC

I'm not sure what would be the solvent for Pavegard. I've never rated the stuff, so I don't know the tech data, but there are pretty nasty solvents out there that would get rid of it, one way or the other.

It definiitely needs to come off before the flags can be properly cleaned and then re-sealed.
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Jock Stewart
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Post: # 36506Post Jock Stewart

I have now spoken with the manufacturer of PaveGard. It is a water based co-polymer product and the recommended removal process is by hot water pressure washing at minimum 100bar as as near to 100 degrees as possible.(Solvents can be used but not recommended) Given the amount of moisture this would put into the stone it was advised that it would need to dry out for a period of months before resealing could be contemplated! I'm sure Roger may have some useful comments on this process
I'm a man you don't meet everyday!

Kevin Magill
Mission 251
Professional Hard Surface Cleaning
www.mission251.co.uk

Tony McC
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Post: # 36507Post Tony McC

You could steam clean it, I s'pose. That reduces the volume of water involved, and then assuming we get a summer this year, come late July it should be moisture free and ready to be sealed with summat sensible.
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RAPressureWashing
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Post: # 36508Post RAPressureWashing

If Pavegard have said a hot wash to remove the sealer then that is the way forward really. Just a case of renting in a machine now unless you have heat on your set-up.
If you don't you could try this company www.robojet.co.uk
Forget that they are a jetting company first and formost as they do a very nice hot water trailer set-up. They do have a rental side, not sure if they rent out the hot machines though but got to be worth a call.
Or you could try Tensid www.tensid.co.uk/Hire_Service
Roger Oakley BDA(Europe)Member 2006
R&A Pressure Washing Services Ltd
info@rapressurewashing.co.uk
www.rapressurewashing.co.uk

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