Posted: Wed Jul 07, 2010 4:12 pm
Kota black/black limestone/lime black will fade in col because the surface is attacked by acidity in the atmoshere not uv rays etc . The reaction causes calcium blooming which is the whiteness you see on the paving. To restore the col you need to remove this but to do it properly is impossible, sand blasting is the only real answer but as soon as it is cleaned it will begin to turn white and the process will start again.
If you can get it clean the best sealer on the market is Romex but even after a few months it will turn white.Marshalls have had huge claims under their 10 year gtee scheme.
Any form of acidity will make the stone go white , patio cleaner, brick acid, jiff, surface cleaners, even lemon/ orange juice.
Many people are trying to develop sealers but have yet found an answer for this stone.
If you can get it clean the best sealer on the market is Romex but even after a few months it will turn white.Marshalls have had huge claims under their 10 year gtee scheme.
Any form of acidity will make the stone go white , patio cleaner, brick acid, jiff, surface cleaners, even lemon/ orange juice.
Many people are trying to develop sealers but have yet found an answer for this stone.