QUESTION

I have a problem with a white dull film stain on a large area of floor tiles in a commercial kitchen. I don't know what I m using to cause this stain. I have try almost everything on the market for tile cleaner and nothing work. I was told the tile isn't seal. I'm desperate at this point to found out what cause this stain. If you can put a test on the tile to found out the type of tile. color, and the type of chemical on it that would help us a lot. Let me know what would it be cost . Thank You Paul

ANSWER

ANSWER - To determine how to remove a stain, you first need to know and understand what type of tile you have.  Since it is in a commercial kitchen I will assume it is an unglazed quarry tile of some type, which is typically used for these types of applications.

Unglazed tiles can be very dense and low absorbing or they can be more porous.  Traditional 6x6 inch quarry tile is normally considered a vitreous body that has up to 3% absorption.   These tiles might or might not have been sealed.  Sealing a tile doesn't make it completely non-absorbing, so they can still stain under the wrong conditions.

So it sounds like you are saying you have done something to try to clean this floor tile that has resulted in the tile developing some white dull film stains.

Sometimes when you use a lot of water to clean a porous tile it could cause efflorescence staining, which is normally a white calcium based stain.   The water goes down into and below the tile and into the concrete substrate.  The water absorbs minerals, which are a form of salt.  The minerals dissolve in the water and as the water migrates to the surface as a result of the drying process, it precipitates this white material.  Normally a slightly acid solution such as vinegar will dissolve it.

If the tile was sealed it is possible that water is trapped within the body of the tile that is causing this stain.  If this is the case then a sealer stripper needs to be used to remove the pre-existing sealer, which should remove the stain.

If the tile is a porous tile, it is possible that you have stained it with a material that absorbs into the tile.  There are poultices that can be used to pull various types of stains from porous materials.  If it was an oil based stain you can try a product that I have seen work over concrete called "Chomp Pull It Out!  Concrete Stain Remover."

It is possible that if you used a corrosive acid such as muriatic acid on the tile that you can acid etch the tile surface.  By etching the tile surface you have altered the physical condition of the material and there is no way to fix it.

It is possible to evaluate stains in a testing laboratory, but it might not be practical from a cost point of view depending on your situation.  The stain can be evaluated with an electron microscope to see if there is any visual evidence of what caused it.  If there is a foreign material in the tile, it can be chemically analyzed to determine what kind of material it is, which would help you decide how to remove it; if possible.

So it is a trial and error process.  You have to be careful not to cause more damage.  Always test what ever materials or methods you use to remediate the problem to make sure it will work satisfactorily before applying it to the entire floor.