Shower Project

[ss3964spd]

Mike, the installation instructions state that the seams between the Permaboard panels need to be finished with mesh tape and mortar then, to make those seams water proof, a roll on/brush on water proofing needs to be applied. Alternatively, you could use a water proof sheet membrane band (typically about 5" wide) installed using mortar. So while you don't need to cover the entire panel you do need to cover the seams.

Originally Posted by Mike

If I use it, I plan on using kerdi and mesh tape over the seams using the Go Board sealant.

Not sure what you mean by using Kerdi and mesh tape, use one or the other on each seam and in the corners. If you apply one or the other using the Go Board sealant the joint will likely still flex, defeating the purpose of using mesh tape (or membrane) embedded in mortar; which is to strengthen the joint to prevent cracks in the tile. Also ignores the Permaboard manufacturers installation instructions.

But, since you are proposing what amounts to a floating tile installation, maybe it just doesn't matter how you seal those seams and corners.

[eagle4x]

Dan,
ok, my bad...thought you meant entire board needed waterproofing membrane applied...you meant only the seams. Thanks.

[eagle4x]

On page 13 of the Permabase WP installation guide under Joint Reinforcement it states "In wet-area applications, apply approved fluid applied waterproofing per manufacturers recommendations over entire surface to receive tile".

However, this is contradictory to the product overview: "Permabase WP is perfect for instances where liquid waterproofing has historically been applied over cement boards" (implying that a liquid membrane is not required).

Therefore don't understand why this would be advertised as a waterproof board if an approved fluid has to be applied over the entire surface.

I'll contact mfg. to ask.

[Tile & Stone Guild]

Joint reinforcement section refers to waterproofing 2" either side of the joint and screw penetrations. Not the board in its entirety.

[eagle4x]

I posted below in another thread (edited since then because of new info.) I started but decided to start a new thread because it's a different topic.

1) May switch to Permabase waterproof board instead of GoBoard foam board:

Since I'm unsure how much GoBoard foam board will flex after all screws and shims installed, I'm considering using Permabase waterproof board (aka Permabase WP) since it's much more rigid and not as likely to flex.

On page 13 of the Permabase WP installation guide under Joint Reinforcement it states "In wet-area applucations, apply approved fluid applied waterproofing per manufacturers recommendations over entire surface to receive tile".

However, this is contradictory to the product overview: "Permabase WP is perfect for instances where liquid waterproofing has historically been applied over cement boards".

So, I don't understand why it is advertised as a waterproof board if the installation guide says fluid waterproofing should be applied over the entire surface.

I'll call the mfg. to clarify if a liquid membrane needs to be applied over the entire board and if it does then I won't use it and I'll use the foam board.

If the mfg. says no liquid membrane needs to be applied on the entire board, do you think better to use the Permabase waterproof board vs the foam board?

2) Shimming:

There are many places on the studs where there's either from 1/32" to 1/8" gaps that's going to require a lot of shimming if foam board used. If I use permabase WP will it be necessary to shim the studs perfectly plum because the Permabase is a lot more rigid than the foam board and because small gaps can be compensated for when thinset is applied?

This is so frustrating because of the shimming I've done so far using cardboard, after I shim a stud it's plumb vertically using my level but not plumb when I put my level horizontally across it all the other studs on the wall...suggestions?

Is it allowed to post links in threads regarding products/product information?
__________________
mike

[ss3964spd]

It's pretty straight forward, Mike. While the panel itself is water proof the joints between panels are not. Exactly like foam board.

[ss3964spd]

Many project threads touch on many different topics; drywall, electrical, plumbing, framing, and eventually tile. It helps all the contributors here to keep all questions and answers relating to a project in one thread so we can understand the history. We've therefore merged your two threads since they concern the same project.

We've already touched on the Permaboard water proofing.

As far as shimming goes it doesn't matter what type of wall board is used. The goal is to achieve as flat (flat being different from plumb or level) a surface as possible and that is best done before the wall board goes up. Using thinset mortar to fill in low spots isn't what that product is meant to be used for. It is done, of course, but typically for only a few square inches.

When installing wall tile it also helps to have the walls plumb, especially at corners. The larger the tile the more important flat and plumb are.

It is tedious work. I wouldn't sweat 1/32", but would anything 1/16" or more. Get one corner stud plumb and flat then start going down the line with your level. as you can imagine a 2' level isn't going to cut it; you'll need at least a 4' level, and preferably even longer. The longest I have is 6.5'.

[eagle4x]

I will be installing permabase WP backer on my separate shower soon. The shower is adjacent to the tub that will not have a shower and will have drywall (blueboard) installed around it.

I saw a youtube video showing to do the transition, thinset applied between the backer and drywall and mesh tape applied over them. However, I'm not ready at this point to install the drywall around the tub, therefore, I am considering one of two methods for the transition after the tile installed:

1) Install tile so that 1" of it overhangs the backer and wipe off any excess thinset behind the 1" of tile. Install edge of drywall under the tile until it's butted against the backer. Then apply a bead of adhesive to the schulter strip and slide it underneath tile until covers edge of tile. Apply bead of caulk between schulter strip and drywall.

2) Install tile so completely covers backer then install schulter strip. Butt drywall against backer except for small expansion gap. Then apply bead of caulk between it and the drywall.

Which one of the above (or other method) better?

[cx]

I would recommend you install the drywall before tiling that transition. If the transition occurs outside the wet area, as it really must, you can finish the joint with drywall compound or thinset mortar. You need only bed and tape the joint with no further finish required.

This transition is on the same plane or a corner?

Not sure the purpose of the "blueboard," or similar MR board if it will be in a dry area such as your tub surround, but that's up to you. Unless required by your local code compliance inspector, I'd eliminate the MR board and use regular drywall. If you want to treat the tub surround as a wet area by choice, I'd recommend you use CBU there and a waterproofing membrane.

My opinion; worth price charged.

[ss3964spd]

Install all the wall board first.

The edge of the drywall should fall on, and be attached to, a stud. If you attempt #1, and assuming there is a stud where it needs to be, you won't be able to screw the drywall into the stud.

[eagle4x]

@ Dan,
There are studs where backer will meet with drywall.

[eagle4x]

I saw a youtube video where someone installed 4" wide rubberized self adhesive roof flashing against the studs so that the edge of flashing looped over the lip of the pan.

Good idea to do this or not?

[cx]

If you're using a moisture barrier behind the wallboard as your water containment system for the shower, I can see that being a functional addition. Whether it would work well would depend upon the framing and the application of the weather strip.

My opinion; worth price charged.

[Davy]

I use the same material when tiling tub surrounds. I then lap my tar paper over the flashing. It's much easier than trying to get the tar paper to overlap the tub.

[eagle4x]

@ CX,
If water penetrates backer board, wouldn't using a moisture barrier cause mold? If no, why not?

I'm using Permabase WP (waterproof board) for my 2 wall shower and mfg says it's 100% waterproof. Regarding moisture barrier, the mfg instructions say to refer to building codes.

I'll use thinset and mesh tape on the seams and apply a 5" wide kerdi band over the seams/corners, and applying GoBoard sealant over the screw heads. Therefore, no water should penetrate through to the studs. However, if water does, wouldn't be better to treat the face of studs with a water sealer like Thompson's water seal, or apply 1.5" wide kerdi only to the face of the studs using an adhesive, or applying the self adhesive roof flashing to the studs vs using a moisture barrier?

The separate shower is adjacent to the tub and one back wall of the shower and one back wall of the tub, on the other side of them is the hallway:

1) Since the tub is a jacuzzi, I purchased some Rockwool to install between the studs to help minimize sound from the jets. If I decide not to use a moisture barrier in the shower, do you think would be a good idea to install the Rockwool between the studs of the shower?

2) I am using 24" x 48" porcelain tile in the shower and one row of it to be installed along side/back of the tub with GoBoard for the backer. Above the tile, I'll be installing 4' of green board that will extend to the ceiling. The tub has only a handheld pull out shower head that extends from one corner of the tub. Because the drywall is not waterproof, should a moisture barrier be installed behind it just in case there is water penetration into the cavity from use of the handheld shower?