If you have a pale stone floor such as this Limestone floor at a property in Brockdish you will find this article very interesting. Let me start by saying it’s always recommended that natural stone tiles such as Travertine or Limestone should be sealed after laying but before grouting. This is particularly important if the stone is very pale in colour as the water from the grouting compound can soak into the edges of the porous tiles leading to dark staining around the edges of each tile – this is referred to as “picture-framing” which is virtually impossible to correct as the staining is present throughout the whole depth of the tile.
Also, without the protection of a sealer smears of grout left on the surface of the stone after grout can be extremely difficult to remove. This problem is often called “grout haze” or “grout smears” which you will find is slightly rough to the touch and because of this attracts dirt easily giving the pale floor a very unappealing dirty appearance which is impossible to wash away with generally available cleaning chemicals.
In this case, and to avoid the problem with picture-framing, our client had decided to apply a penetrating sealer all-round the edges of each of the tiles using a paint brush to ensure a thorough soaking. Unfortunately, he left the main body of the tiles unprotected and although he was able to wipe away grout from around the edges of the tiles it left a fine, slightly opaque film of grout in the middle which set and became firmly bonded to the tile surface.
Initially, all seemed to be fine but shortly afterwards our client noticed that the floor appeared to be developing lighter patches around the tile edges and the grout lines were becoming noticeably dirty; in reality, what was actually happening was that the middle area of the tile contaminated by grout haze were becoming dirtier by the day, whilst the sealed outer edges were responding well to cleaning. Additionally, because the grout itself had not been sealed the dirt from cleaning was becoming stained with the dirt that had been washed into the recesses during cleaning
Ordinarily, the way to correct a grout haze issue is to apply an acidic solution to the haze which dissolves the calcium-based grout material and makes it simple to rinse away; this is fine on ceramic tiles but can cause all sorts of surface etching issues and problems if the tile material is also a calcium-based stone like travertine or limestone. It was at this point that our client decided to get some help from a stone flooring renovation specialist such as ourselves.
Removing Grout Haze and Dirt from Pale Limestone Tiles
Having contacted us through the Tile Doctor website and after a brief exchange of emails, it was obvious to me what the problem was, and being aware of the issues surrounding Limestone I was soon able to propose an effective solution.
Our first job was to apply a strong solution of Tile Doctor Pro-Clean which is an alkaline cleaning product designed for use on tile, stone, and grout. I used a strong dilution and applied it by hand to all the grout lines where it was allowed to dwell and soak in before being briefly agitated using a long-handled grout brush. Pro Clean is an extremely effective degreasing cleaner and, at higher concentrations, can also be used to strip acrylic floor finishes. It was the ideal product for sorting out the grout issues and in this instance made quick work of lifting the soiling pout of the grout lines.
Rather than rinsing the Pro-Clean away, we left it in contact with the floor and proceeded to cut the surface using a Tile Doctor 400 grit diamond burnishing pad fitted to our 17″ Klindex rotary machine. These coarse diamond pads applied in conjunction with the Pro-Clean removed all the grout haze and soiling. The resulting slurry was then power rinsed and extracted away using a Ninja 400psi machine, leaving the grout clean and the once picture-framed tile surface with an even and consistent colour.
After the application of the coarse pad, it was time to restore the appearance of the stone and bring up the polish, first with an 800-grit diamond burnishing pad followed by a 1500-grit, power rinsing and extracting between the stages. This left the floor completely clean with the beginnings of a pleasing overall sheen. We then left the floor to dry out thoroughly overnight with assistance from our large capacity dehumidifier.
Sealing a Pale Limestone Tiled Floor
On our return the following day, we were pleased to find that the Limestone had dried up extremely well which we confirmed by taking moisture content readings with our damp meter just to make certain that it was ready to have a sealer applied.
Before sealing, the surface sheen was improved further by spray burnishing the stone using the Klindex rotary fitted with a Tile Doctor 3000-grit burnishing pad. Lubricated by a fine mist of plain water from a trigger bottle this process raised the sheen level to a more noticeable shine and brought out areas of visually pleasing coloured veins within the structure of the stone which had been completely invisible up to now.
Having completed the burnishing, we applied a liberal coat of Tile Doctor Ultra-Seal which is a penetrating sealer approved for use in food preparation areas which provides excellent fluid resistance yet is almost invisible. Having allowed the limestone to soak up as much of the sealer as it could, the excess product was removed, and the floor left to cure for an hour.
We then finished the process by spray buffing the floor with a white nylon buffing pad to remove any smears left by the sealing process and to polish the floor to a rich shine. Once vacuumed thoroughly, we conducted a series of fluid resistance tests to ensure that the whole floor had been sealed properly against liquid spills and our work was done leaving behind a very pleased, impressed, and grateful client.
For aftercare cleaning of a polished stone like this floor I recommend the use Tile Doctor Stone Soap which gently cleans the floor whilst helping to maintain the patina.