Calcified effloresence? How to remove it

[tibor]

Hi there,

It Tibor from Sydney, down under. I am havign a problem on a job where we are doing floor safet acid etching treatment, near the harbour. The manager asked me to have a look at some tiles that we have not treated. It seems that some tiles have more effloresence than others and on top some of the tiles the original terazzo like tile surface disappeared under a cement looking
hardened material, which I think is calcified effloressence. I managed to take it off with a knife, but could not advise the manager what to do about it.

It is near Sydney harbour on a warf. I think the fefloressence is coming up as the concrete below was not sealed before the tiles were laid and it contain water as it stands in water and this will keep the bottom of the tile when which will bring up effloressence.

I still would be interested how the close to .4 mm think hardened calcified salt could be removed and prevented to regrow. I've tried to acid etch it, but we do not penetrate deep enough (only around 15 to 20 microns) to remove it. With the knife I've managed to remove some of it :tongue: and the tile look OK below.

Could anyone advise whether I am correct to ifentify it as effloressence and also to advise how to remove it? :bang:

[Sponsored Links]

[doitright]

Hi Tibor :)

I think you're on track. The problem may or may not go away. The mechanical scraping is the best way I know how to get the thick part off, followed up by a chemical cleaning.

The problem is the moisture below. There needed to be a bed with a drainage matt installed below. Right now all you can do is attempt to clean it off, and maintain it.

[tibor]

Thanks John for your advice.

What sort of chemical would you advice to use and with what dilution ratio?

As it is on the harbour and outdoors, (salt water and more rain) the environment is more favourable for secondary effloressence to appear.

[doitright]

Hi Tibor :)

You'll need an acidic based detergent. My biggest concern is the terazzo type tiles that probably have a cement matrix. You want to be careful not to burn or etch them. Check with your local tile or masonry yard for products available (to remove efflorescence). Start with a higher dilution ratio, and go stronger as needed. As always, do tests first!