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Posted: Tue Aug 10, 2004 3:39 pm
by John17
Has anyone got any tips for removing the staining that some times occurs when pointing and laying slabs?
Posted: Tue Aug 10, 2004 4:41 pm
by alan ditchfield
This depends on these three things; what sort of mortar what sort of flags and how long have the stains been left on the flags for. Alan
Posted: Tue Aug 10, 2004 11:22 pm
by 84-1093879891
There's some basic tips on the
Dealing with Stains page.
Don't use any acid-based cleaner with imported sandstones.
Posted: Sat Aug 14, 2004 9:36 pm
by mouldmaker
I'd like to throw my tuppenceworth into the ring by advising against using acid cleaners on precast concrete paving. The tips offered on the 'Dealing with Stains' pages are fine, but I cannot emphasise enough the pre-wetting, followed by application of acid. Don't allow thw acid to penetrate; better several applications than disaster.
Overapplication of acid may cause discoloration, and a visible degradation of the face. It can also damage resistance to frost and make them prone to dusting. My advice would be, unless the staining is minimal and easily removed, replace the affected slabs.