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Posted: Mon Apr 21, 2008 9:10 pm
by stevieb
Hi, i have been looking through the posts and see that using patio cleaners with acid is a definite no no. I was wondering whether i could use a 10% solution of citric acid as i do not believe this is as agressive as the standard patio cleaner acids. (though i do not own a white coat and so may be wrong on this).

Posted: Mon Apr 21, 2008 9:20 pm
by Pablo
What are you trying to clean off the flags?.

Posted: Mon Apr 21, 2008 9:43 pm
by stevieb
Hi Pablo, i am trying to clean off mortar marks as the patio was black limestone, was only laid last august and now looks like light grey !!

Posted: Mon Apr 21, 2008 10:21 pm
by Pablo
Limestone will go grey if you don't seal it soon after laying. Maybe try powerwashing with a turbo lance and a 3000+psi washer. Stay away from your pointing. Tiler's use alkaline cleaners for this kind of thing but I have never had to use them. Power wash it then test a samll area with a QUALITY sealer and see if it covers the problem over.

Posted: Mon Apr 21, 2008 10:58 pm
by stevieb
thanks for that, any recommendations for the quality sealer ?

Posted: Mon Apr 21, 2008 11:14 pm
by Pablo
Lithofin stay away from the cheapies like Thompsons they'll break your heart. I get mine from a tile shop.

Posted: Wed Apr 23, 2008 9:14 pm
by RAPressureWashing
Be careful with Citric Acid, you could turn your Black limestone White, citric is usually used as a brightner or neutraliser not a cleaner.

Posted: Wed Apr 23, 2008 10:40 pm
by stevieb
OK, many thanks for that. I have been advised to wet the patio and if the marks dissappear then i should be ok to just seal it only.

Posted: Thu Apr 24, 2008 7:02 pm
by Pablo
Nooooooooooooooooo! Once the sealent weathers the marks will start to show through again pretty quickly. Get them off as best you can then seal it.