Hemlock,
Sealing the grout line with a silicone sealer or another grout sealer will help keep stains to a minimum, and help a little with water peneration. I would go that route instead of trying to use plain silicone on everything. Also, some grouts have been fortified to help with this, but many people add the sealant as well. NEVER use grout sealants you SPRAY on.

To help, just make sure your tile edge next to the tub ledge is caulked with a blended silicone/latex caulk. Doing this in the corners next to in the lower portion is helpful. I really don't suggest just plain silicone because it is awful to get off, and difficult to control in a bathroom setting. The combo of silicone/latex works very well for joint areas.

Do you know what they used in materials behind the tile? Cement board or something else? Some tile installers who use cbu will also use something like a waterproof membrane that is a liquid you apply, In an older method, Some will just use a thick plastic behind the cbu. It depends on how much the tile installers keep up on the industry.

cyberheater,
Thanks for the reply. I was looking at using the silicone more as a sealer for added protection from water/moisture penetration as opposed to preventing staining.
As to the tile/tub ledge, he also used grout there, which I later found out he should have used a silicone bead instead. (all grout used was sanded)
That's another reason I was thinking of now doing the silicone over the grout. Do you think I should remove that grout 1st on the tub/tile ledge or would I be OK just using the caulk over the grout?
As for materials behind the tile, he used cement board & hardi-backer.
I also thought he should have used plastic sheathing for a vapor barrier (this is an outside wall) but he said it wasn't necessary with the hardi-backer.
All in all I wasn't too impressed with his work. If I wanted to take the time to do it myself & with some guidance along the way, I know I could have done a better job.

Hemlock, first - he might of thought that the hardibacker would have created a "water diaper", because there are those who think it is impervious to water. Hardibacker does not deteriorate with water, but it does absorb water. The phrasing with this is confusing to people.

Do not try using your basic tube of silicone. You will be disappointed. Use a grout sealer (some of silicone in them). Tec has one called just that.

Just use the caulking over the grout.
Sanded or not, grout may have been fortified and/or modified with something to help fight mold and water, although none of them (unless epoxy) is all that water proof.

Again, I suggest a silicone/latex blend of caulk. And yes, you can put it over the grout - no harm there really. Grouting at the joints is not bad, some installers think do not grout at joints if they are worried about cracking/movement. Grouting, then caulking is done a lot.

Although silicone seems like the best, try removing it once signs of mold (little black spots) start to appear. No bleach will get rid of it. If you use something that you can easily remove and replace in a couple of years, that silicone/latex blend works very well. It does help resist water and you can remove it and apply it much better.

My advice a grout sealant is not to get one with a lot of solvents in it and not to use some "off" brand. Go with those brands that have a good name for it. NO SPRAYS - period.

Sorry, need to add something Hemlock. The grout does need to dry out a little - even if you use a grout sealant it should do that somewhat - another reason not to cover everything in silicone caulking.
Your installers also may have used (most typically) a fortified thinset.

If you tile job looks good, and you are not taking a lot of showers per day - you may be okay. Just do your maitenance. Watch for water problems just outside of the tub where water splashes too.

If you live in a location where you do not get extreme temps outside, you outside wall may be okay too, I couldn't be certain.

cyberheater,
Just so I'm clear on this & we're on the same page, when you speak of a grout sealant & the latex/silicone caulk, are you referring to 2 different things or one & the same? The only grout sealants I've seen in Home Depot are liquids. (& yes some are sprays) So far, the only thing I'm referring to is the silicone caulk. When you mentioned Tec, is that a liquid or the caulk? Are you saying get the grout sealer that comes in liquid form, then use the latex/silicone caulk over that?
Like I said, I just want to make sure I'm on the same page as you.
I'm in western NY, so we get the extreme temps like yourself in MN.
The job was completed over a month ago, so I believe the grout should be cured by now. Usually only 1 (sometimes 2) showers per day.

Sorry for not being clear enough.

Grout sealant - liquid brush on.
Tec has a grout silicone sealant. There are others that are good. Once this has dried (follow manufacturers instructions) Then caulk using the silicone/latex combo.
Only caulk at the joint of the tub line and in the corners from the tub up about 8 - 12 inches. Don't try and cualk the all the grout lines. I also caulk at shower/tub faucets, handles and shower heads. Also shower doors.

You can also find caulking that is close to the color of your existing grout in the tile section of some stores that will work.

I never have not used a vapor barrier, unless I am using one in the inside of the shower walls. Depending on the age of your home, you may have something already installed on the outside. Wrap, or tar, or even foam board. (I am trying to help you relax a little)

Next tile project - look into the Kerdi system from Schluter. You can Google it. Still labor involved, but I have installed it enough to tell you that it's a very good solution for tiling showers and bath surrounds.

OK, now I'm clear on everything.
Have you ever heard of SurfaceGard grout sealer by TileLab? I bought a pint of it about a week ago at Home Depot, (About $18) but haven't opened it yet. I'll look for the Tec product if you think that's better & return this stuff.
Thanks very much for your input... much appreciated.

cyberheater,
I re-read your last post about the colored grout in the tile store & forgot to mention something. The guy who did the work left me a tube of Superior Adhesives Pro-caulk that is 100% acrylic siliconized & matches the tile grout. He never did say how/where to use it & I didn't ask, but I've used some around the new medicine cabinet where a couple small gaps weren't filled. Is that the same (or close to) the latex/silicone caulk you're referring to & would it be good for going over the grout in the areas around the tub?

That pro- caulk may work good for you, and since it is at least close to the color of your grout, give it a try.

Tile lab has given a bit of "shaky" reviews. I would use something from Aqua mix. They have both water based and solvent based sealers. Very important to test a little area of grout of this sealant first.

Then follow instructions. Tile type and grout type does help to jknow in purchasing your sealant.

Tec I have only used on occasion. No problems with it, but I like to use something that screams "works".

Remember - this is not a "waterproof" solution, but it will help with stains and allow what moisture in the grout to dry. All grouts need to dry.

Also remember to read the directions on whather or not to quickly wipe off that sealant off the tile. Not all sealers do the same. You can go to the aquamix site and take a look before you go purchase something.

Good luck Hemlock.

OK, thanks again cyberheater.
I'll take back the sealer from Tile Lab & look for Aqua Mix.
Very much appreciate all of your input.

It is 2 1/2 years old question... Start new thread

Cement board or Wonderboard is NOT waterproof Hardibacker is better for showerwalls where they will get wet daily. Felt, tile and grout will breathe(let the water and moisture thru) if you are using wonderboard then plastic sheeting is recommended.

Why would you be concerned with what is the min. you can do verses doing what is best for your investment? Always go far and beyond so you will know you did the best you could to secure your investment. Also think about if you ever sell your home and what type of home you'd be selling another human being. A few extra hundred dollars is NOT going to keep you from eating or paying your mortgage. We bought our home five years ago and it had a beautiful bathroom so we thought. We had to rip it all up because mold was growing underneath the tile, mortar and backer board. ALWAYS go beyond the min. code requirement because our homes should carry our pride. If you cannot afford to go the extra mile, then save your money until you can.

Designer from IL.