strange colouring patio

golfergirl28

We've had new patio laid. All lovely. Patio layer gave it a clean with Cementone Patio cleaner. Still all lovely. Now after a shower of rain the sand and cement grout mix has turned a ghastly shade of orange/brown like rust. It won't scrub off but when I hosed it, bits migrated to the slabs and stained them too.
I phoned the maker of Cementone and they say there must have been some iron content in the sand/cement mix. How do we get rid of the staining? Is it going to come back every time it rains? I'm really upset.
Do we have to remove the grout? And how? Help!

golfergirl28

Ok. It's now pretty certain to be rust stains. Something in the patio cleaner reacted with some iron content in the sand/cement mix and caused the staining.........initially in the grouting only. However with the rain the staining has now migrated and my lovely new grey slabs are now a horrid yellow colour. Sorry, don't know how to post photo. Any ideas on 1. how to prevent further rust and 2. how to remove current rust staining.

bobhawke

What was used to point the slabs? What is the name of the slabs used for your patio?

Have a look at this link for some methods that can help remove rust stains:
http://www.pavingexpert.com/stains.htm#rust

golfergirl28

It was a sand and cement mix to point the slabs. The slabs are silver grey sandstone. The patio was cleaned with Cementone and this appears to have been the problem.........but initially only with the pointing. The heavy rain carried the rust over the slabs and now they're really badly marked with rust stains.

bobhawke

Was there any dye mixed through the mortar for the pointing?

sunshinetours

What does your patio layer say about this (assuming it wasn't a friend or family that is) ?

golfergirl28

There was no dye in the mix. The person who laid the patio is actually the chap who did all the tiling in the house. The patio is beautifully laid! He's absolutely bamboozled. He's been back and used another patio cleanser but to no effect. We've tried vinegar, even a cleaner for alloy wheels that someone suggested. Nothing makes any difference. Would bleach be worth a try? Or what else? Is sandstone so porous that nothing will shift the marks? I'm really upset.

bobhawke

golfergirl28 wrote: »

There was no dye in the mix. The person who laid the patio is actually the chap who did all the tiling in the house. The patio is beautifully laid! He's absolutely bamboozled. He's been back and used another patio cleanser but to no effect. We've tried vinegar, even a cleaner for alloy wheels that someone suggested. Nothing makes any difference. Would bleach be worth a try? Or what else? Is sandstone so porous that nothing will shift the marks? I'm really upset.

Don't use bleach, it will make it worse. Whoever laid your patio shouldn't have needed to use acid to clean it and even if they did they should have tested it on an off cut of the stone, especially since it is sandstone, to make sure nothing like this happens.

sunshinetours

golfergirl28 wrote: »

There was no dye in the mix. The person who laid the patio is actually the chap who did all the tiling in the house. The patio is beautifully laid! He's absolutely bamboozled. He's been back and used another patio cleanser but to no effect. We've tried vinegar, even a cleaner for alloy wheels that someone suggested. Nothing makes any difference. Would bleach be worth a try? Or what else? Is sandstone so porous that nothing will shift the marks? I'm really upset.

The point I was making is that if you have paid someone to do something and it has now gone wrong - then the person who had been paid should be the ones to correct the issue. If they then wish to persue a claim against the manufacturer that is then up to them

Sounds to me like you may need a new patio laying if something has got into the sandstone itself.

Some types of sandstone are indeed very porous

golfergirl28

Bobhawke posted a link which suggested lemon juice, vinegar and oxalic acid. Tried the first two.........no difference. A friend had a little oxalic acid which I've just used on a couple of slabs. It's dark out there now but I think there's some improvement! Will know better in the morning but I've already ordered some online. I'm hopeful!