I have white grout in my bathroom. Sanded on floor, unsanded on shower walls, if that matters. They're starting to discolor in, and in front of, the shower. What's the best product to use to get them as white as the rest of the floor? A green/pet friendly product is preferred. Thanks.
With phosphoric acid and bleach. (Neither one being green nor pet friendly but when you finish reading this long post, you'll know what to do, how to do it and why you're doing it that way.)
Mildew is like everything else, it needs to eat to survive and grow. In the case of bathroom mildew, the food source is the vegetable oils (notably Palm oil and Olive oil) used to make the BAR SOAPS people use when having baths and showers. You can actually not only prevent mildew growth in bathrooms, but also not have soap scum rings around your tub and sink if you switch from a bar soap to a detergent, like Aquanil or Cetaphil, which are both lipid free skin cleansers, which means they aren't made from vegetable oils and don't have vegetable oils in them.
The best way for you to proceed is to buy a cheap window squeegee, a very stiff plastic bristle brush like the grout brushes you can buy at any hardware store or a denture cleaning brush. You will also need some phosphoric acid based toilet bowl cleaner and some bleach. Note that not all bleach is equally strong; look for Javex or Chlorox that will be a full 6.25 % NaOCl. A jug of no-name bleach will be slightly weaker at only 5 1/2 or 5 percent NaOCl.
Don't buy a hydrochloric acid toilet bowl cleaner of any strength or a phosphoric acid toilet bowl cleaner stronger than 20 percent phosphoric acid. You just want to dissolve the very surface layer of grout and the soap scum plugging up that surface layer, not dissolve all of the grout. Phosphoric acid is the active ingredient in most general purpose bathroom cleaners because it dissolves soap scum quickly but won't attack chrome even at high concentrations.
Only clean an area of about 4 to 8 square feet at a time, depending on the size of your tiling. The bigger the tiles, the less grout lines you have and the bigger the area you can clean and the faster you can go.
Squirt some phosphoric acid based toilet bowl cleaner onto the tile and wipe down the tiling with the rubber squeegee to move the acid into the grout lines. Then scrub those grout lines with the stiff bristle nylon brush. Continually scrub the dirty grout and move it back into the grout lines and you should start to see the grout whitening as you kill mildew and disolve dirty soap scum. Keep an eye out on the grout as the acid will dissolve the very surface layer of the grout, and that's all you want and need to do. Don't leave the acid on the grout for longer than about 10 or 15 minutes.
Now, rinse the tiling off, dry with a towel and move onto the next 4 to 8 square foot area.
Once you've cleaned all of the mildewed grout, allow 2 days or so for the grout to dry completely so that capillary pressure will draw liquids into the grout.
Now, use your stiff bristle nylon brush to apply undiluted bleach to the remaining discoloured areas of your grout. It's best to do this on a weekend where you can keep applying bleach every hour or two to kill any remaining mildew growing inside the grout. I've applied bleach starting on a Friday afternoon and ending on a Sunday night, stopping only to sleep. As long as you can see you're making progress whitening the grout, keep applying bleach.
If some areas don't whiten up from the bleach, it could be that the surface porosity of the grout is still clogged up with soap scum, and you should give those areas another shot of phosphoric acid to dissolve the soap scum and surface layer of grout.
This method should remove MOST, if not all of the discolouration caused by mildew, but you still might have to replace some grout if you can't get it perfectly clean. So far, in 25 years of maintaining a building with 21 tiled bathrooms with showers, I've had to replace less than 10 lineal feet of wall tile grout.
After bleaching the grout, rinse it off with clean water and again, allow time for the grout to dry so that it'll wick in liquids.
Now, apply an acrylic film forming grout sealer. Custom Building Products makes a decent one they sell at Home Depot. It's sold under the "Tile Lab" brand name and comes in two gloss levels; "Gloss Sealer and Finish" and "Matte Sealer and Finish".
I don't think that Gloss or Matte Sealer & Finish is significantly harder or more water resistant than anyone else's acrylic film forming grout sealer, but what I do like about it is that Tile Lab also makes a chemical to strip this sealer off quickly and easily that REALLY WORKS WELL. It's called "Heavy Duty Cleaner and Stripper":
and you just paint this stuff on with an old tooth brush or squirt it on with a spray bottle and within a few seconds you can scrub the sealer off with a piece of green Scotchbrite pad or a stiff plastic bristle brush.
However, it's not often that you'll ever need to strip the sealer off completely in your shower. Most of the time you'll be applying more sealer to keep up the protection against mildew. But, stripping off grout sealer from all the grout in a shower area can be an awful lot of work, and so having a grout sealer that makes that chore easy is at least one good reason for buying that particular sealer.
If the idea of waiting 2 days for the grout to dry sufficiently to wick new liquids in is a problem, you can also dissolve any acrylic grout sealer with acetone (aka: nail polish remover) which you can buy for about $30 per gallon at most hardware stores. Acetone evaporates very rapidly without leaving a residue which might interfere with the adhesion of the new grout sealer.
If you live in California, or knows someone who does, get them to send you some grout sealer made by the "Glaze N' Seal" company which goes under the straight forward name "Grout Sealer". This is the acrylic film forming grout sealer that I use in my 21 bathrooms, all of which are tiled, and all of which have showers. I've very happy with the performance of this grout sealer so far.
However, there's no cleaner available that will take Glaze N' Seal Grout Sealer off quickly and easily, so you have to use acetone to remove it.
I use "Script" artist's paint brushes. The "Script" isn't a brand name, it simply means that the brush has longer bristles than an ordinary artist's paint brush for less dipping and less dripping. If you can paint a straight line with an artist's paint brush you can seal grout. Put on 3 coats of sealer, and it's been my experience that you'll be good for at least 7 years, at which time you should simply clean your tiling with any general purpose bathroom cleaner (like Zep Shower, Tub and Tile Cleaner) also available at Home Depot and who's active ingredient is also phosphoric acid, only this time at a much lower 6 percent concentration,
rinse with clean water, dry with a towel and then allow a good few hours for the surface of the grout lines to dry completely. Then apply another three coats of acrylic film forming grout sealer.
But, when you reseal grout above a bath tub, you really don't need to reseal ALL of the grout because soapy water seldom splashes high up on the rear wall of the shower enclosure. If you draw a horizontal line through your shower head, another horizontal line half way up the tiling at the back of the tub and connect those lines with a diagonal, then the area below that line is all that you really need to do when you reseal grout. The initial 3 coats you put on over everything will normally be enough to last the entire life of the tiling above that line. Any mildew growing above that line is just growing on the surface of the grout sealer, not on the porous surface of the grout, and can normally just be cleaned off with a paper towel damp with bleach.
I own a small apartment block, and I know that the success of my business, the resale value of my building and ultimately the kind of retirement I enjoy depend heavily on my being able to keep my bathroom tiling clean and attractive and that means free of mildew. So, how to remove mildew and keep it away is something that I take very seriously.
PS: Look on the fine print of any grout sealer you buy for the word "siloxane". "Anything siloxane" means an anything-silicone based plastic, and the problem with silicone based plastics in general is that nothing sticks well to them. That's especially true for silicone caulk, and it's common to find newbies in these kinds of forums asking how to get new silicone caulk to stick properly around their bathtubs after they removed the old silicone caulk. Really, what the problem is in every instance is that the newbie hasn't removed the old silicone caulk COMPLETELY, and there's still a thin film of silicone sticking to the tile and tub and as long as it's there, nothing, not even new silicone caulk will stick to those same areas.
So, the problem with using a siloxane or "silicone based" film forming grout sealer isn't that it won't protect the grout just as well as any other grout sealer, but that no other grout sealer will stick well to it. So, when it's eroded down from the shower spray, you DON'T have the option of just applying more sealer because the new sealer won't stick well to the old sealer. You have to strip all the old sealer off, and then apply new sealer, and that can be quite hard to do. So, while silicone based plastics (like silicone caulk and silicone based grout sealers) work well, they have the inherent problem that you can't just apply more caulk or grout sealer and expect it to stay in place.
Acrylic film forming grout sealers don't have that problem. Each coat of acrylic film forming grout sealer will stick well to any previous coat of acrylic film forming grout sealer as long as that previous coat is clean. Both the Tile Lab sealers and the Glaze N' Seal Grout Sealer mentioned above are ACRYLIC film forming grout sealers, and there are many others available as well.
Hope this helps.This message has been edited. Last edited by: Nestor,
If you go the way of removing it, a Fein or a Dremel with a grout removal bit will make it a lot less painless than using a screwdriver. I promise. Both are superb multi-use tools to own that can be used on a lot more than removing grout, as well.
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