How to remove grout stains from natural stone flooring
When installing natural stone, you are confronted with many problems that can be overcome if you master your material and the installation/handling procedures. As always and for such a design project, we recommend you to work with a team of skilled professionals in natural stone, because they have experience and will avoid risks. You can always ask for help from an expert in natural stone, who can give you exactly the steps for installing and aftercare of natural stone.
Daniel agreed with his contractor’s advice for flooring: he selected Anthracite Black Slate (riven finish, slip-resistant), a natural stone with amazing results for a decoration project.
But, every decoration project has its story and Daniel experiences unpleasant things. “For the interior, the contractor used a grouting joint applied all over the tile surface, allowing it to dry just like that. After realizing they made a mistake, they used Keranet (from Mapei), an acid solution, with a steel wire brush for angle grinder. In the end, all the stains were still visible, so I had to take care of it personally!” said Daniel.
This was the look of black slate flooring after trying to clean the stains with acid solution and steel wire brush for angle grinder, even after applying a coat of sealer over the grout stains.
First, they attempted to clean the grout (after being left to dry on the tile) with an acid solution and steel wire brush.
Then, they attempted to apply a sealer over the tiles already installed and stained with grout and even after applying the sealer, the grout stains were still visible.
What went wrong?
First mistake was allowing the grout to dry on the tile. It is very important to clean the remained grout on the edges, immediately after installation, with a sponge or dry cloth.
The acid solution remained on the tile too much, it was very powerful or not enough rinsed. The developed stains were traces of dry grout, bleached from acid crystallization. The sealer used for the attempt to recover the tile was not the right one.
Read also on “The correct steps that should be followed for installing natural stone flooring”
How to avoid this?
First and foremost, you do not allow grout to dry on the tile; wipe it immediately after installation. A team of experts qualified in natural stone installation is responsible for all stages of this project: installation, grouting and sealing.
Since sealer is based on oil, LTP Stone Oil is more recommended for taking care of this situation.
Then, if for a number of different reasons you are confronted with a similar situation, we recommend washing the surface with LTP Grimex and LTP Power Stripper, using a single disk washing machine with soft brush or pad (grout has to be removed very efficiently) and next, test it with LTP Stone Oil, for help with color restoration (since it is oil-based, it could be helpful in similar situations). This was also the solution used by Daniel, and the flooring regained its look.
Is it more difficult to grout slate (the dark color stone), compared to other types of natural stone?
The dark color exhibited by some types of slate is not a problem, when grouting/sealing was made by a qualified team – the steps are similar to those of installing any other type of natural stone. So, color alone isn’t the problem, but the professional attitude of the person who install it.
For dark colors, here are some sealers that can be used:
LTP Color Intensifier 1L = 10 sqm (sealer based on solvent for enhancing the color, without “just washed” look).
LTP Glaze Protector 1 L = 10 sqm (a sealer for enhancing color, with “just washed” look).
LTP IronWax Satin 1L = 10 sqm (a sealer for enhancing color, with “just washed” look).
If you do not want to modify or enhance your color, use LTP Mattstone, 1L for 1 sqm.
All these solutions are based on stripping with LTP Grimex, 1 L for 50 sqm. Plus, the secret is the aftercare with LTP Floorshine, a daily cleaner for repairing the cleaned surface, with a price similar with standard cleaners.
For more details on natural stone aftercare or sealers recommendation, give us a call at + 40318.222.333 or better visit our showroom from 137 A, Aleea Teisani, District 1, Bucharest!