6 thoughts on “Why did the black grout stain my tile?”
EA Canning says:
Hello, a bathroom install completed this week and yesterday noticed several of the porcelain tiles from Maravilla are turning brown around the edges. Grout is light grey and contractor said used a white thin set/. I’m so upset.
Donato Pompo says:
Technically porcelain tiles are impervious that typically has an absorption rate of less than 0.1%. So it is unlikely it is absorbing a stain. If it is a glazed porcelain tile the glaze is also impervious, but sometimes they have micro fractures called crazing. Some manufactures do this intentionally to give a distressed look, but sometimes it happens unintentionally.
If the glaze has fractures, then when tile is grouted the grout pigment can get imbedded into the fracture and it can be difficult to remove. That is why grout manufacturers always say use a grout release (sealer) prior to grouting when grouting with a contrasting color grout.
In terms of removing it, first you need to determine if it is trapped pigment. If so sometimes a slightly acidic tile cleaning solution with a brush will remove it. You can try using a stone poultice to draw it out. Whatever you do it is trial and error. You have to test out the method before applying it to the entire application to make sure you will be satisfied with the outcome.
Albert Fernandez says:
I tested some glazed porcelain tiles for lead using testing swabs with sodium rhodizonate, which are supposed to change color if there is lead in the glaze. The swabs did not change color but purple showed up on the tile glaze itself. Does this mean that the glaze does contain lead? If you don’t know, could you refer me to someone who would? Many thanks.
Donato Pompo says:
Whether your test protocol was performed was valid or not according to the appropriate ASTM test protocol, would have to be determined in order to determine the validity and meaning of your rest results. You should search for an Industrial Hygienist in your area to have them evaluate your findings.
Dean says:
Morning Donato, I’ve used black grout on a white porcelain tile and I’ve tried various acidic products neat to clean it to no prevail. Is there anything I can do to clean it. Fortunately I grout 2 walls which I can tile over again and I know now to use a sealer before applying the grout.
Just want to know if there’s anything out there I can use.
I’ve used LTP Grout Stain Remover also a porcelain grout stain remover from topps tiles.
Nothing is shifting it.
Donato Pompo says:
Technically porcelain tiles are impervious that typically has an absorption rate of less than 0.1%. So it is unlikely it is absorbing a stain. If it is a glazed porcelain tile the glaze is also impervious, but sometimes they have micro fractures called crazing. Some manufactures do this intentionally to give a distressed look, but sometimes it happens unintentionally.
If it is an unglazed or throughbody porcelain tile, it too is impervious, but there can be outgassing during the firing in the kiln that can leave micro pores where pigment can get trapped into it.
If the glaze has fractures or pores, then when the tile is grouted with a contrasting color grout, the grout pigment can get imbedded into the fracture and it can be difficult to remove. That is why grout manufacturers always say use a grout release (sealer) prior to grouting when grouting with a contrasting color grout.
In terms of removing it, first you need to determine if it is trapped pigment. If so sometimes a slightly acidic tile cleaning solution with a brush will remove it. You can try using a stone poultice to draw it out. Whatever you do it is trial and error. You have to test out the method before applying it to the entire application to make sure you will be satisfied with the outcome.
There is no full proof method for removing the staining. You have to experiment with trial and error.
Hello, a bathroom install completed this week and yesterday noticed several of the porcelain tiles from Maravilla are turning brown around the edges. Grout is light grey and contractor said used a white thin set/. I’m so upset.
Technically porcelain tiles are impervious that typically has an absorption rate of less than 0.1%. So it is unlikely it is absorbing a stain. If it is a glazed porcelain tile the glaze is also impervious, but sometimes they have micro fractures called crazing. Some manufactures do this intentionally to give a distressed look, but sometimes it happens unintentionally.
If the glaze has fractures, then when tile is grouted the grout pigment can get imbedded into the fracture and it can be difficult to remove. That is why grout manufacturers always say use a grout release (sealer) prior to grouting when grouting with a contrasting color grout.
In terms of removing it, first you need to determine if it is trapped pigment. If so sometimes a slightly acidic tile cleaning solution with a brush will remove it. You can try using a stone poultice to draw it out. Whatever you do it is trial and error. You have to test out the method before applying it to the entire application to make sure you will be satisfied with the outcome.
I tested some glazed porcelain tiles for lead using testing swabs with sodium rhodizonate, which are supposed to change color if there is lead in the glaze. The swabs did not change color but purple showed up on the tile glaze itself. Does this mean that the glaze does contain lead? If you don’t know, could you refer me to someone who would? Many thanks.
Whether your test protocol was performed was valid or not according to the appropriate ASTM test protocol, would have to be determined in order to determine the validity and meaning of your rest results. You should search for an Industrial Hygienist in your area to have them evaluate your findings.
Morning Donato, I’ve used black grout on a white porcelain tile and I’ve tried various acidic products neat to clean it to no prevail. Is there anything I can do to clean it. Fortunately I grout 2 walls which I can tile over again and I know now to use a sealer before applying the grout.
Just want to know if there’s anything out there I can use.
I’ve used LTP Grout Stain Remover also a porcelain grout stain remover from topps tiles.
Nothing is shifting it.
Technically porcelain tiles are impervious that typically has an absorption rate of less than 0.1%. So it is unlikely it is absorbing a stain. If it is a glazed porcelain tile the glaze is also impervious, but sometimes they have micro fractures called crazing. Some manufactures do this intentionally to give a distressed look, but sometimes it happens unintentionally.
If it is an unglazed or throughbody porcelain tile, it too is impervious, but there can be outgassing during the firing in the kiln that can leave micro pores where pigment can get trapped into it.
If the glaze has fractures or pores, then when the tile is grouted with a contrasting color grout, the grout pigment can get imbedded into the fracture and it can be difficult to remove. That is why grout manufacturers always say use a grout release (sealer) prior to grouting when grouting with a contrasting color grout.
In terms of removing it, first you need to determine if it is trapped pigment. If so sometimes a slightly acidic tile cleaning solution with a brush will remove it. You can try using a stone poultice to draw it out. Whatever you do it is trial and error. You have to test out the method before applying it to the entire application to make sure you will be satisfied with the outcome.
There is no full proof method for removing the staining. You have to experiment with trial and error.