It's best to seal grout right after it's installed. This helps preserve it when it's in its newest state, before it has a chance to deteriorate and become damaged. But that doesn't mean that grout can't be sealed later in its life. This will keep it in the best shape possible until it's time to reseal or replace.
A. You can seal the grout the day after you applied it or 100 years later. If it isn't dirty, seal all three sides of the shower with a tile sealer or masonry sealer. That will make the grout water-resistant, if not waterproof, and help prevent the growth of mold and dirt.
Grout is porous and therefore absorbs liquids. Because of this, the reason you should not seal your tile grout is that the sealer's liquid chemicals combine with the grout to create a surface that is actually much more difficult to clean.
Prevent Mold & Bacterial Growth
The reason for this bacteria and mold growth is water build-up. If grout is not protected, water can build up and allow bacteria and mold to grow. The tile sealant stops the water from absorbing into the grout.
Porous grouts attract water, dirt, oils, etc. While the tile industry does not require sealing, it is always recommended, especially in wet or high-traffic areas. Penetrating sealers are the most commonly used and offer high water, chemical and stain resistance.
Epoxy grout is also the most expensive grout choice, however, it doesn't need a sealer, which can save time and money in the long run.
Grout sealer helps make the grout more water resistant, aiding in it's longevity and minimizing its ability to become stained and dirty. Since grout is a cement based compound, the more water that interacts with it, the weaker it will become. This leads to cracking and crumbling over time.
Myth #4: You can't seal old grout!
To do so, just put a few drops of water on the dry grout and see if it beads up and sits on the surface or soaks in. If the water is absorbed and completely disappears into the grout, it's time for a reseal!
Sealing wall and floor tile grout in your home can be very beneficial. This is particularly true in shower or bathroom areas where moisture, shampoo and soap residues can cause hard to remove staining and contamination.
For high-traffic areas, like the main bathroom, you should consider sealing it every six months, while low-traffic areas like the guest bathroom can be resealed every two years. If you are using epoxy grout, it might not be necessary to reseal it as it is highly water-resistant.
Moisture and direct water contact contribute to grout deterioration over time, and eventually, the tiles will crack. This is why you should consider regrouting shower tiles every six months.
Grout sealer will not harm porcelain tiles if it gets on them while you are working. That said, it can dry clear and shiny, and this may be noticeable. It may be particularly visible if you have bright or overhead lights in the space where the tiled floor is located.
However, you must make sure you are re-grouting with the same type of grout you originally used. If not, the second layer will not adhere well to the first and you will have to do the same job over again in a few months' time.
ANSWER - It is possible to grout over existing grout if there is enough depth to do so. 1/8 inch depth may or may not be adequate depending on the type of grout used. A latex modified grout may work, but you have to properly clean the existing grout to ensure the new grout adequately bonds.
Grout haze occurs as a result of waiting too long to wipe grout from your tiled surface. Call The Grout Medic if you're seeing this problem.
While penetrating sealer leaves no shine and will not alter grout color,impregnating sealer may darken your grout slightly. Non-penetrating Grout Sealer- these types of sealers form a film or barrier on the surface of the grout. This barrier helps to repel water and stains.
You can sometimes tell if your tile or grout has been sealed by spreading a few drops of water on them. If they darken or change color, they are probably not sealed. If they stay the same, they may have already been sealed.
Assess the Grout
Another way to check if the grout has been sealed is to monitor the water beads. If the water beads flow done from the ground, it is correctly sealed. However, if the grout absorbs the water, either the grout hasn't been sealed or the sealer has worn off.
So we get this question a lot…”How do I know if my tile needs cleaning?” and the answer believe it or not is quite simple: Find an area of your tile that is not exposed to normal soiling and traffic and compare the grout line color in that area with the grout color in the rest of the floor.
Crumbly grout happens most often when the grout used was standard grout rather than epoxy grout. Standard grout is a fragile and brittle material when it dries and hardens. It usually happens over a period of years, but if a floor is not supported very well, it will crack and eventually crumble and chip out.
Too Much Sealant:
Not every sealant job is the same and some surfaces are more porous than others. If you do not account for the varying levels of porousness, you may apply too much sealant. The excess will produce a haze.
Be sure to let your grout sealer dry thoroughly before testing a small area with a few drops of water. If the water beads up, you're all set! If not, you'll need to apply an additional coat of sealer to your grout. Most grout sealers take 1-3 coats for best results.