Designing Kitchens and Bathrooms - "Rust" stains in grout in natural slate shower?
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maestroperu
10-01-07, 08:12 AM
I recently had a contractor remodel a small bathroom. Instead of tile, we installed 12x12 slate everywhere, including the shower walls and floor. He also used sanded gray grout, but it was regular, not epoxy. (I realized after the fact that epoxy would have been better for inside the shower, but we decided to just several coats of sealer rather than redoing it).
The problem is that some of the slate, being natural stone, apparently has a high metallic content, which is causing the gray grout in a few selected grout joints to develop what appears to be a slight “rust” film and become a bit orange. (The grey grout in the shower floor, which is constantly wet, is not orange-ish but appears constantly darker, which itself may be a problem).
What is the best way to prevent the grout from become orange? The contractor re-grouted the problem sections, and we applied a lot of sealer, but the issue re-developed after just a couple of weeks. He told me that “grout sealer” is not like polyurethane – the sealer seals, but doesn’t create a protective film like poly would. As a result, even though the grout is sealed, it eventually “rusts.”
I have been wondering whether to apply spar urethane in the shower floor and walls, but I really don’t want to do that, because I think it will eventually peel and create a mess. I have also though about interior-exterior lacquer – at least, if it peals, it can always be easily re-coated with more lacquer or removed with lacquer thinner – but it will probably not last long. I think, but may be wrong, that the problem will continue even if we apply epoxy grout (if it’s available in gray), unless we put a clear protective film. I have also been wondering whether this is just the result of the slate’s nature, and I can do nothing about it and just get used to it.
Incidentally, regardless of the “rust” issue, should I absolutely have the shower re-grouted with epoxy grout? If so, I guess I will wait for a while before doing so, unless I must do it asap.
Thanks
The problem is that some of the slate, being natural stone, apparently has a high metallic content, which is causing the gray grout in a few selected grout joints to develop what appears to be a slight “rust” film and become a bit orange. (The grey grout in the shower floor, which is constantly wet, is not orange-ish but appears constantly darker, which itself may be a problem).
What is the best way to prevent the grout from become orange? The contractor re-grouted the problem sections, and we applied a lot of sealer, but the issue re-developed after just a couple of weeks. He told me that “grout sealer” is not like polyurethane – the sealer seals, but doesn’t create a protective film like poly would. As a result, even though the grout is sealed, it eventually “rusts.”
I have been wondering whether to apply spar urethane in the shower floor and walls, but I really don’t want to do that, because I think it will eventually peel and create a mess. I have also though about interior-exterior lacquer – at least, if it peals, it can always be easily re-coated with more lacquer or removed with lacquer thinner – but it will probably not last long. I think, but may be wrong, that the problem will continue even if we apply epoxy grout (if it’s available in gray), unless we put a clear protective film. I have also been wondering whether this is just the result of the slate’s nature, and I can do nothing about it and just get used to it.
Incidentally, regardless of the “rust” issue, should I absolutely have the shower re-grouted with epoxy grout? If so, I guess I will wait for a while before doing so, unless I must do it asap.
Thanks