Kerdi Shower Floor: To seal grout or not to seal

[WeekendTileWarrior]

Hello everyone. I just want to start by saying thanks to this forum, because it has helped me do my best tile job ever. I am not a tile setter by trade, just a home improvement guy, but I love working with tile.

I am finishing up my first kerdi shower at my home. I have read some stuff that suggests to me that it is possibly counter-productive to seal the grout on a tile shower floor that is over kerdi. Is this true? The claim is that the water that gets between the tile and the kerdi on the pan cannot evaporate out in between showers....

The shower floor is constructed with 2" porcelain squares that have 1/8" grout spaces. I have not grouted it yet.

Any recommendations for how to proceed? Should I seal the floor grout or should I not seal the grout?

Thanks,

Ryan

[Lazarus]

That is incorrect, Ryan. A sealer does NOT make the grout "waterproof," it simply makes it a bit easier to clean. Some seal the floor, some don't.

Recently I've taken to using "Quartzlock" grout on shower floors. Premixed and a tad pricey but easier than epoxy, holds true colour very well and never requires sealing.

[doitright]

Hi Ryan, Welcome!

As long as you use an impregnating sealer, you'll be good. They allow vapor transmission, thus don't trap moisture in the grout. Don't use any products that use the terminology "Finish and Sealer". They are topical coatings that will fail quickly in a wet environment and need to be stripped.

[jadnashua]

Think of grout sealer more like Scotchgard for tile...it helps to repel dirt and grim, but not necessarily actually waterproof anything. The grout can still get wet, but it will repel a lot of grime.

[WeekendTileWarrior]

Unbelievable responses everyone. Thanks a lot for your advice.

I do have some Miracle 511 Impregnator that is 2 years old....they give it a 12 month shelf life.......what do you think?

If not, I also have some new Dupont Bulletproof that I used on my granite. Would you use this for the grout or should I just go get more 511?

[doitright]

Hi Ryan

You can either pour the 511 into a clean clear container and establish if there is a foul smell, discoloration, chunks, or any other contamination. If everything appears normal, you should be good to go.

Your BulletProof can also be used. Do not allow it to dry on the surface of the tile, or puddle in the grout (without wiping it before it dries). Otherwise there is a risk of fogging the grout joints.

[StoneTooling]

Both products are great. We notice if the products are kept at a safe temperature, the shelf life is a bit longer. As mentioned above, pour it into a clear bucket and see if it looks suspect. You should be fine as long as it wasn't subject to heavy humidity or freezing conditions.

If it's questionable, the BulletProof is also a great product.