Indian Sandstone Picture Framing/Grout marks

[1sandyh]

Thank you JCR! The woman I spoke with was J (not sure if I’m allowed to say full name on here?)

 

[Dumbo]

Right I have just had a reply from grout manufacturer's after talking to technical and their reply is this .
(The stains are left by incomplete rinsing of the surface and when the water evaporates it leaves the calcium salts.

Brick acid may be too strong for Indian sandstone. There are other acid based products that can be used. Lithofin Builders clean (acid based) need to seek advice from the stockists. Start of by diluting it 10/1 and incrementally increase the dosage if required,this should shift the stains. If you are unsure do a small test patch first in an indiscrete area.)
Sorry no silver bullets .

 

[1sandyh]

Cheers JCR. Same advice I had from Lithion. It didn’t work so was advised try 3-1 or 4-1. Used 4-1 left on for 20 mins, scrubbed and scrubbed like I’ve never scrubbed before! Rinsed. Next day looked at them dry. Nothing had changed. So went even stronger almost used it meat, left m, scrubbed constantly, rinsed. You guessed it didn’t budge. I used 4 L bottles on area of approx 20m2. Thanks for your help I’m literally at my wits end with this

 

[Dumbo]

@Lithofin BOB I'm certainly no expert but is it worth the householder spreading builders clean and then sheeting down with plastic sheet to allow it to work for longer .

 

[Spare Tool]

Ive just text a link to thread to Lithuanian Bob as he hasn't been on for a while...

 

[1sandyh]

Thanks so much for helping out. Apologies for my terrible spelling in the last post. Should have said I used it almost NEAT, scrubbed, left for 20mins then scrubbed more. Really hoping someone can help me find a solution to this. Looking forward to Bobs opinion

 

[Waluigi]

Try the paving expert forum. Not knocking anyone’s advise on here by any means, just saying that this sort of thing is very common on there.

 

[1sandyh]

I’ll post there too then. Hoping Bob appears soon

 

[Zane Sio]

Interesting, any update? thanks

 

[Lou]

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