The answer to the question is, surprisingly, no. Tile and grout is not totally waterproof and neither is cement board, backer board, sealers and cement adhesives, they absorb water but do not block penetration.
Bear in mind, grout is not waterproof, only water resistant and once cracked, water is most assuredly going to get behind it and probably damage the wall, unless the wall or floor was properly sealed with something like Kerdi first.
Grout and tile are NOT waterproof. Water will penetrate and pass through both grout and tile if saturated enough.
Standard grout isn't waterproof at all, only epoxy grout is. You can seal regular grout after it dries, but you have to do it every so often or else the grout will begin to absorb water again.
Whoever installed your floors most likely did not seal the grout because it needs time to harden and cure completely.
Grout Works proprietary grout sealer penetrates into the grout lines and dries as hard as the tile forming a permanent, protective barrier against stains, discoloration and bacteria.
Epoxy grout doesn't need to be sealed at all.
But typically, you will need to leave for at least 72 hours to make sure that the grout has cured properly and won't be compromised when exposed to water. But if you are using epoxy grout this only needs to be left for at least 24 hours.
A renovator tool with a silicon carbide tip will make short work of the old grout. Be careful how deep you grind out as damage to the waterproofing can be expensive to repair, and may require retiling the whole area.
Curing will not be required in totally submerged conditions. However, when cast above water, Dayton Superior recommends using a Dayton Superior curing compound, cure & seal or a wet cure for 3 days. Use clean water. Hardened material will require mechanical removal methods.
For clear defects in the tiled shower surface, grout replacement will usually rectify your water leak. However, re-grouting a shower that is leaking due to a missing puddle flange or other building or structural issue, probably would not make a difference.
The most common reason grout crumbles and disintegrates with minimal force is water - too much water. Virtually all powdered wall and sanded floor grouts are made from Portland cement. Some grouts have additives, such as powdered latex or acrylic modifiers, that make them bond even better.
Most manufacturers of slurry grouts advise to keep the area damp with a sprinkle of the hose. So a very light shower can help to ease application and stop the slurry from drying on slab surfaces. However, anything heavier than a light drizzle is way too much rain for a slurry mix to cope with.
While you might be using ceramic tiles in your bathroom under the belief that they are waterproof, the truth is that they actually aren't fully waterproof.
Cement-based grout is by nature porous, and therefore not waterproof. It can be water repellent when modified with an additive, either latex or polymer-based, which effectively fills the micropores in the cement at a molecular level.
Cement-based grouts are porous, and if they aren't sealed, they can absorb moisture. This moisture will eventually build up behind the walls and cause extensive harm. As we mentioned above, you may not notice it right away, and by the time you do, you may already have a lot of damage.
With waterproof grout there is no water absorption, no discoloration and no disintegration. Mapei Ultracolor Plus FA grout is waterproof and stain-resistant (unlike regular cementitious grout) and is actually used for indoor/outdoor pools, spas and hot tubs.
Grout is porous and usually sealed to resist stains. However, acid can degrade these silicone-based sealants, causing them to break down and wash away. Contrary to popular belief, this can happen with just one application of vinegar.
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.
A question we're often asked is, “how long should grout last in my bathroom last?” Grout doesn't last forever and has a lifespan of between eight and sixteen years, depending on your upkeep and treatment in your shower area specifically.
Being naturally water-resistant, Epoxy grout is an excellent choice if you plan on laying tiles in your front or back garden. Epoxy grout is made up of a unique blend of a filler powder form grout and epoxy resins, making it the best grout to use for outdoor projects.
To maintain the integrity of grout, you will have to apply a grout sealer. It is necessary to apply the sealer after 1 to 2 years so that the grout remains intact and waterproof. Sealing grout is necessary because it without a waterproof covering it absorb not just water but bacteria and stains as well.
Can a grout be Mold resistant? Yes, a cement based grout is naturally mold resistant. Mold and Mildew cannot live or grow on cement, this is a misperception because soap, cleaning fluids, oil, food, and other contaminants are left on the surface of the grout, feed the mold and mildew, and allow it to grow.