I have laid grey Indian sandstone paving, two weeks ago, and after rain it is leaching out a rust colour residue which I assume is iron oxide. Does this leaching indicate a poor quality stone? i.e. excessively porous. The stone was not crumbly at all but I wonder if there is a lot of oxide in it will it expand with rain weathering and eventually fall apart? How much leaching out is too much and how long will might it continue to do so? I could post pics if that helps.
Thanks for any thoughts.
Leaching iron oxide - How much is too much?
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Tony McC
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Many of the Indian sandstones have relatively high Iron Oxide (rust, in the vernacular) which means cleaning them with an acid-based cleaner is a big problem. The top quality flags have lower FeO levels, but some of the chgeaper, shoddier imports are known to have a bit of a rust problem. Sadly, most retailers fail to mention this when selling flags, so there's a tendency amongst the general public to think that all the flags are the same.
As stone is a natural product, you could just have a bad batch of flags, or it could be a short-lived temporary phenomenon that will dissipate in a couple of weeks.
As stone is a natural product, you could just have a bad batch of flags, or it could be a short-lived temporary phenomenon that will dissipate in a couple of weeks.
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