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BillyB44 · 09-04-2008, 03:36 PM

Quick question. By the time I got the HardieBacker up around the window, there is about a 3/16" gap between two pieces. Do I need to remove them and make the fit tighter, or will the mesh tape and mortar handle this gap ok??

Nestor_Kelebay · 09-04-2008, 10:09 PM

If you've already bought your thin set, I'd just mix up some thin set and fill the gap with that. Otherwise, you could just fill it with any caulk that happens to be handy that your Red Guard will stick to. It prolly wouldn't stick to silicone.

BillyB44 · 09-06-2008, 07:29 PM

So I got the RedGuard and will apply it tomorrow. Question: must it cover the entire backboard, top to bottom, or can I just do the bottom 1/2 or so where the water will hit? Or will the thickness of the Red Guard (they want 60 mils) make an uneven surface for the tiles if it doesn't cover all of the backer board? If you follow me.

Nestor_Kelebay · 09-06-2008, 11:42 PM

It's the bottom portion of the wall that you want to ensure is well coated with RedGuard. But, if you've got a 2 gallon pail to do a single bathroom, you're going to have pleny left over.

I'd give the whole wall two coats and then use up the rest of the pail on the bottom 2/3 to 3/4 of the wall. And, put extra coats on the front wall below the shower head and on the side wall at a 45 degree angle (kinda) toward the front wall. Basically, I'd paint the whole tub surround twice, and then put extra coats where it's going to be most needed until you run out of the stuff.

Nope, nuthing is going to show through your tiling.

BillyB44 · 09-07-2008, 02:44 PM

Actually, it's just one gallon, rated at 65 sq. foot coverage, I think (it's down at the cabin right now.) I want to make sure to cover the lower 1/2-2/3 really well and, as you suggest, below the shower head entirely. I was worried there might be a slight unevenness between no coverage and thick coverage areas. I'll do like you say, if I have enough, and bring it to the top of wall as well, but concentrate on the lower portions.

marcoj32 · 09-07-2008, 04:03 PM

5.) Seal seams with silicone. Mesh and thinset.

What abourt the inside corner wall seams. How do you mesh those corners after the silicone sealer?

Nestor_Kelebay · 09-07-2008, 09:51 PM

Billy: I'd consider buying another gallon of Red Guard. 60 mil is thin, and it's not going to affect the appearance of your tiling. However, that Red Guard is the main water barrier between your ceramic tiling and the stuff in your wall that will rot and mold & mildew if it stays wet, like the wood and insulation. I wouldn't skim on the Red Guard whatever you do.

Marco: You really can't use mesh in the corners. I wouldn't use silicone in the corners either. I'd just fill those corner joints with the same thin set you intend to use for tiling, and paint the Red Guard over that corner. You'll be tiling into the corners and grouting the corners as well. And, if push comes to shove and the grout in that corner cracks, you can also silicone the corners.

When cutting the tiles to fit in the corners, don't cut them to fit well cuz the grout won't stick to just the glazed surfaces of the tiles. You want to cut them to have a gap between the tiles that the grout can root itself in.

And, if you're concerned about using silicone in the corners cuz it'll eventually mildew, that's not a concern either. There's an easy and VERY EFFECTIVE way of cleaning mildew off of silicone caulk: Just mix up some bleach (straight out of the jug) with baking soda to make a paste, and trowel it onto the silicone with a 1 inch putty knife and spread with a teaspoon. Cover with Saran Wrap and leave overnight like that, or for several days. When you pull the Saran Wrap off and remove the bleach/baking soda paste, your silicone caulk will be white as Manitoba snow. I own a 21 unit apartment block, and that's how I clean my silicone caulk. And it works very well indeed.

The only problem with the above is that the baking soda sinks to the bottom of the paste quickly, so right now I'm experimenting with using VIM "Thick Bleach" which is a gelled bleach and baking soda to make a more stable paste that won't gravity segregate as fast, and that will stick better in vertical corners.

BillyB44 · 05-13-2009, 08:05 PM

Well, the job is done (see pic--which doesn't quite show spout) but I have a plumbing problem. The tub spout is now too short to reach the threaded pipe end with the added thickness of the backer board and tile. Is there any way to extend the pipe about 1/2" with a screw-on extension or do I have to sweat on a new piece or...???