Quick tile/grout question
 

I'm entering the grouting phase of my bathroom remodel. I looked on the interwebs, and everything I found said to use caulk any place where there's a change of plane, ie in the corners. Great. However, I've been checking out tile everywhere I go, and all I've seen is grout in the corners. In restaraunts, at the gym, other people's houses etc - I have yet to find one that's got caulk in the corners instead of grout.

What gives?

Trek will be along, but I agree, no caulk in vertical corners. The key word is "vertical".

They make sanded caulking to match sanded grout.

Just grout it.
If it cracks, you can touch it up later.

Seal the grout first.


KT

I already bought some sanded caulking to match the grout.

The very bottom, where the tile meets the shower pan, was going get caulk.

You're saying I should go ahead and grout the vertical corners?

Thanks!

Grout is your friend (especially when sealed), caulk will discolor eventually.

I've not had problems with grout in the corners, but silicone in the corners isn't a bad idea, as long as it matches well.

We always left the gap between the pan and the walls open to allow any moisture to escape.

Silicone at the joint of the shower pan (if you have one) and the floor tiles prevents squeaks there.

A tile floor and walls looks the best IMHO.

You can leave the bottom line of grout out, if you want.

The modern sanded caulking is fairly durable and colorfast.
How much flex on the subfloor when you stand in the pan?

I heard some people preload a tub or pan with weight while grouting.
This supposedly prevents cracks. ( I've never tried it )

What color did you choose?

KT

There doesn't appear to be much flex on the subfloor.

The color my wife chose is called "alabaster"

http://forums.pelicanparts.com/uploa...1304041435.jpg

I prefer to just grout with no caulking.


KT

The grout color with that decorative strip plays tricks on my eyes!

Looks like a dark dot in each intersection in the picture.

Grout color can do that.
There is a display with a black and white pattern with white grout.
looks normal.
With grey grout, it looks bendy and wavy.
The eye can't focus on the white or the black due to the mid shade tone of the grey.

Weird.


KT

I was going to use caulk down here

http://forums.pelicanparts.com/uploa...1304042306.jpg
http://forums.pelicanparts.com/uploa...1304042322.jpg

I see you have one of each, non-sanded and sanded.

The stuff is tricky to use.

Pipe it into the joints and wash it like grout.


KT

It's not only preloading, but the heat expansion when hot water hits the pan/tub vs. walls.

Then, when things cool, the crack opens. Not a whole lot one can do. The sanded caulk would be good if it retains flex.

I grouted the horizontal along the tub and it cracked. I removed the grout and replaced with caulk. 2 years down the road still good. By the way, I read similar info about caulking wherever there is a change in plane, but ignored it. I also caulked where the tile floor meets the tub. My verticals, corners, are fine with grout. You have to remember there are different thermal expansion properties between the tub/shower pan and the tile so you will eventually get cracks where these 2 different materials meet.

Let's examine the characteristics of the materials used:

Grout is composed of a hard base(silicates/?/etc), a little adhesive, and a lot of water to make it flow. Just like drywall mud, applying a very thick layer guarantees there will be cracking after the water dries.
While the base material does dry rock-hard and sheds most surface water, it does absorb some moisture. Thus, the silicone sealer.

Caulk can be partially latex-based. "Latex" as in latex rubber and/or just thickened paint. Non-sand able but flexes with the surfaces. It is harder to find decent pure latex caulk anymore though because everything has silicone in it. Bathroom caulks at the bottom edge should be pure silicone because of it's flexibility and hydrophobic nature. Problem is, pure silicone doesn't stick well to chalky grout or slick tiles surfaces. Cleaning before applying is essential. Mold and/or rust deposits will still build up on the surface. Harsh cleaning chemicals will compromise the seal.

Using either of these materials as a primary barrier in order to prevent moisture infiltration and build-up(mold) behind enclosed bathroom fixture spaces is limited to their continuity and durability.

Personally, I'd suggest grouting fresh tile in two stages to just below surface level. You could rough up the inside edges with sandpaper as well. Then apply caulk 1/8th inch over the edge of the cleaned tile. You can use painters tape to get a clean line. Work fast and use pressure.
The caulk will eventually fail, but there will be something behind it as a backup.

When re-caulking, cut the line with a rounded but semi-sharp blade and remove the excess off the tile with a soft plastic scraper to avoid

A little more work now will prevent ripping everything out in order to re-joice and plywood the floor later on when everything underneath is rotten.

I'm sure if I ripped everything out I wouldn't be rejoicing :)

Remember to allow the water behind the tile to bleed out on the bottom. I have done both grout and caulking. I really like Polyseamseal. Flexes well and it doesn't degrade in 2 -3 years. the only thing is, a tiny bit of water will collect back there and mold will grow especially during winter months. Grout will breath a bit better, but I know it will spit. No big deal with the wetness since it is so little back there.