Bathroom Remodel

[big_rat]

I replaced some of my true 3/4" plank subfloor with new planks but have come to notice the new planks are a little less thick than the old ones. I went to the store and saw most of the flooring is actually 23/32 flooring. The only true 3/4" plywood I saw was a sheathing which had a lot of knots in it.

Do I need to be concerned about this slight difference in height in the bottom layer of plywood? I am adding a second layer of 1/2" plywood on top of the subfloor.

[big_rat]

I measured the new T&G plank at 11/16. Also I have some sanded cabinet grade plywood that is 11/16" thick. Will 1/16 less thickness be a problem or will the second layer of plywood take care of it? I think the old T&G is 12/16" or 3/4" true but its hard to tell. I can definitely feel the lip when the old T&G is next to the new T&G.

[cx]

John, you can either try to find some plywood of matching thickness, add blocking to raise what you have, or replace the rest of your subflooring. The industry standard calls for no more than 1/32nd of an inch difference at the edges of adjoining subflooring. Up to you what you'll accept.

You do not want to use any "sanded cabinet grade plywood" in your subfloor. You want an exterior glue plywood with no face of grade lower than C.

My opinion; worth price charged.

[big_rat]

Thanks cx. I found 3/4" true BC plywood exterior glue at Home Depot and replaced the shorter planks that I installed.

I recently found a company that sells 48" tubs and they have an option to have a factory installed ABS tiling flange glued onto the tub. It looks a bit better than the Kohler stick on tile flange. The instructions say to silicone caulk between the ABS and the tub to seal the gap. I want to caulk it with a slope so any water that gets there would have to go uphill to even reach the flange. After the cement board is installed I'd also like to put a secondary layer of caulk between the board and the tub and then a third layer between the tile and the tub. I think these 4 barriers (abs flange, first caulk, second caulk and third caulk) would be pretty hard for water to get past not to mention redgarding the cement board.

In doing my research I was wondering if silicone caulk is the best choice or should I use Kerdi Fix as it seems to be well regarded here. Do you think silicone sticks well enough to ABS/acrylic plastics? How about Kerdi Fix?

Here is a video of them installing the tiling flange.
https://www.youtube.com/watch?v=CY-iy1WBfNY

Thanks all.

[cx]

Originally Posted by John

I found 3/4" true BC plywood exterior glue at Home Depot...

Mmmmm. Must be a Yankee thing.

I'm opposed to caulking or otherwise sealing the bottom of the CBU in that application, John. That's the only outlet for any moisture that might get into that wall board. I'm also opposed to a continuous caulking of the tile to tub gap in that application, but that's what the current industry standards call for. I would personally recommend at least leaving some gaps to drain the water that will get between the tile and your waterproof membrane.

That's a substantially different add-on tiling flange arrangement than I've ever seen or used and I think I would prefer it to the ones I have used. If it is properly applied, of course.

Caulking between it and the tub wouldn't be a bad idea. I've never tried silicone on ABS plastic. I'd be more inclined to try some SikaFlex or Kerdi Fix or NobleSealant or USG's Durock Sealant or whatever similar pookey you might have about. I've not tried any of them on ABS either, but they stick well to lots of other materials. The 100 percent silicone might also be adequate.

My opinion; worth price charged.

[big_rat]

Ok so you are saying caulk the tile flange, dont caulk the cement board to the tub and caulk the tiles to the tub. Does the sound right?

[big_rat]

Hello all,

What method do you use to shim out cement board for shower walls?There are drywall shims that seem like they would work well except they are made of cardboard. I sprayed one with water and they swelled a bit. The shims would be behind the water barrier for the shower so I don't think they would ever get wet but I want to know what the pros do. Thanks.

These are the shims in question:
http://www.homedepot.com/p/Strait-Fl...rl__W549491099

[Just1]

Really depends on how much you need to shim out. If it's 1/8" you can use Masonite and rip it to the width of the studs. If it's 1/4" you can use lattice molding that comes in 1 1/2" wide and 8' lengths. If it's more than that you can use plywood ripped to the correct width.

[Carbidetooth]

Drywall shims are fine for low spots. Shouldn't be any water where they live if things are done right. Can also sister straight stud alongside. Plane the high spots.

[big_rat]

The lattice molding looks perfect but it would cost so much money to do both walls with it. The stuff in my local home center costs almost $7 for a 96" length piece.

If I get plywood and rip it into 1.5" lengths, do I need exterior grade plywood or can I get whatever is 1/4" or 3/8"?

Thanks!

[cx]

The lattice molding splits much too easily for that application, John. I much prefer to use rips of plywood and I use mostly construction to attach them with enough mechanical fasteners to hold them in place.

Exterior glue plywood would be best, but you can use whatever you find that's the right thickness.

My opinion; worth price charged.

[Just1]

The 1/4" thick molding that I used to furr my studs out was pretty good quality and I predrilled it with a pilot hole. I had no splitting. I only had to furr out the back wall though.

[big_rat]

I am also interested in creating a custom shower niche with cement board and 2x framing. The wall behind where I want to put the niche has drywall. Do I glue the cement board for the back of the niche directly to the drywall using silicon?

[big_rat]

bump

[big_rat]

1) I am also interested in creating a custom shower niche with cement board and 2x framing. The wall behind where I want to put the niche has drywall. Do I glue the cement board for the back of the niche directly to the drywall using silicon?

2) Do you guys use the 2" alkali resistant mesh tape to thinset the outside corners of a custom niche? Will folding it over the edge hold together until the thinset dries?