Grout recommendation and how to get at corners?

Question

I have a shower where some grout has fallen out at the corners, where the walls meet the floor. I went to home depot and they sell a few types of sanded grout (the gaps are 1/8" or more).

I saw a brand named "fusion pro" which does not require any sealer, so it's just one application. Has anyone used this kind? link Or would you recommend sticking with more traditional types?

And lastly, can anyone recommend how to get the grout into these corners? All the videos I've watched are on the flat wall faces and use a float.

Thanks

Answer 1

That grout looks like it should work, the problem is that most grout require you to take out most of the previous grout. Certain groups, such as Mapei flexcolor, is built so you can add more to previous grout jobs, but it might have to be the same type.

As for the corners, you should use a colour matched caulking rather then grout. This allows for contraction/expansion. Most brands of grout have caulking in the same colours to make it easy to match.

Answer 2

As said by LBJ you need flexible caulking (not cementitious grout) as this will follow the walls and shower tub as they move during thermal expansion/contraction. In this situation (corners and along the tub) hard grout will always crack and create leaks.

You need silicone caulking marketed for bathrooms, it will have an anti-fungal agent mixed in. Don't skimp on the price, you'll only use one canister anyway and it's much more convenient if you pick one that won't get moldy in just a year.

Application technique is very important! Watch this. With the proper tool it's quite simple. Proper cleaning is essential if you want it to stick.

I prefer water-based silicone caulk as it is much easier to work with, but it's a rather new formula, I'm not sure how it will be branded in your place.