Questions about installing plastic tub surround?

[EdNerd]

Several years ago, I had to do a bathroom remodel (busted up the concrete foundation to replace the failing cast-iron sewer pipe). We wanted to tile up the walls around the tub/shower, but couldn't afford that right away. I did get the concrete backer board up, but had to settle for a "damp location" wall board.

Fast forward about a dozen years - the wall board is falling apart, so I'm tearing it out and will install a plastic tub surround kit (three panels: back wall and two ends). I also took out the window - I'll be covering that with backer board also (just for continuity ).

Some questions:

-- Videos show applying adhesive from a caulking gun and then spreading it even with a notched trowel. Is there a better adhesive in a tub that just spreads with the trowel? As opposed to the caulk gun and then trowel?

-- What about any kind of moisture barrier between the concrete backer board and the plastic surround walls? Do I need something? Or will a good thick coat of adhesive work just as well? (I'm in SW Arizona: not a lot of moisture here!)

-- On one video, there was some kind of sealing tape used around the bottom tub-to-wall joints and vertical wall-to-wall joints. What is this? When would you want to use it?

Thanks for the assist!
Ed

 

[nealtw]

Welcome to the site. Drywall should be enough behind a plastic tub surround but as you have backer board I would want to stay with it too.
Usually they fill the gaps with thin set mortar and mesh tape.
If the tape you are seeing is red it would be Tuck tape mostly used to tape joints on moisture barrier.

I think they use the adhesive in the tube because it is compatible with the plastic (not sure if that is the only one)
Now the problem you may have, is the glue compatible with cement board.

There is a sealer you can put on the cement board, I don't think you need it but it may help with making the glue work.

Most of these sealers have a color in the name, the one that comes to mind is Redgard. Home Depot carries it. Close to $100 for a gallon and you would use about half of that.

 

[oldognewtrick]

I thought the plastic tub surrounds went direct to the studs? I looked at doing those one time and the measurements of the inside wall was smaller than that of the panels.

 

[jeffmattero76]

Several years ago, I had to do a bathroom remodel (busted up the concrete foundation to replace the failing cast-iron sewer pipe). We wanted to tile up the walls around the tub/shower, but couldn't afford that right away. I did get the concrete backer board up, but had to settle for a "damp location" wall board.

Fast forward about a dozen years - the wall board is falling apart, so I'm tearing it out and will install a plastic tub surround kit (three panels: back wall and two ends). I also took out the window - I'll be covering that with backer board also (just for continuity ).

Some questions:

-- Videos show applying adhesive from a caulking gun and then spreading it even with a notched trowel. Is there a better adhesive in a tub that just spreads with the trowel? As opposed to the caulk gun and then trowel?

-- What about any kind of moisture barrier between the concrete backer board and the plastic surround walls? Do I need something? Or will a good thick coat of adhesive work just as well? (I'm in SW Arizona: not a lot of moisture here!)

-- On one video, there was some kind of sealing tape used around the bottom tub-to-wall joints and vertical wall-to-wall joints. What is this? When would you want to use it?

Thanks for the assist!
Ed

Are you saying that, in the old install, you applied backer board to the studs and then covered that backer board with moisture resistant drywall (called green board around here)? Not a pro, but i dont understand why you would do that.

As far as the new tub surrounds are concerned, if you are referring to the 4 piece surrounds (tub and 3-piece wall surround), those are installed directly to the studs (i.e. no drywall or backer board) and then drywall is added to the walls above the surround after the surround is installed. I have installed about 20 of those in my rentals.

 

[EdNerd]

Thanks for all the replies. Glad I picked the right forums!!

During the previous remodel, I intended to put tile on the walls, so mounted backer board (Hardibacker??) to the studs. Since I couldn't do tile then, I glued a patterned moisture-resistant finishing wall board (not green sheetrock) to the backer board. The wall board is now off, so I'm looking at concrete backer board walls.

During the previous remodel, I installed a new porcelain tub. That is staying in. The tub surround is three pieces - a back wall panel that goes completely across the long way, and two end panels.

I'll dredge up the video I saw the other day that showed the tape. I think it might have been on the Lowes site, but I won't swear to it.

Ed

 

[Snoonyb]

When you installed the "hardi-backer", did it create a a flush transition to the existing wall covering, or was it installed floor to ceiling in "just" the tub area?

Did the "water resistant" patterned, WR board panels, that have since been removed require a stop trim as a transition to the surrounding wall surfaces?

Many of these glue on panel systems, are just that, they are applied to an already prepared wall surface requiring no transitional trim or surrounding wall repair, just a bead of caulk, all around.

They also recommend "silicone" as a caulk.

For me, silicone works best 20' deep in a landfill, unopened.

Use polyseamseal, washable, remains pliable and easily repaired/replaced.

 

[EdNerd]

The concrete backer board was installed tub-to-ceiling in just the tub alcove. The side edges were 90-degree corners to the outside (the tub alcove is about 6-8 inches inset on either side from the bathroom walls), so no transition needed. Same with the wall board.

Here's the videos I watched:
https://youtu.be/n32y0fBj3Ck
https://youtu.be/h64E_8W0rUU

This is the concrete backer board:
https://www.lowes.com/pd/James-Hard...ardieBacker-Fiber-Cement-Backer-Board/3067737

I tried to find the panels I used, but couldn't - and it really doesn't matter now 'cuz they're gone!

Ed

 

[Snoonyb]

Because the texture of the Hardi-backer may not be as visually pleasant as finished drywall, you'd be money ahead in installing a nail on product, instead of the glue on, and then finishing with drywall and paint.

 

[EdNerd]

The tub surround is going over the backer board. What the surround doesn't cover (about 8 inches all around the top) will get tile. Finally!

I'm concerned mostly with any need to seal the backer or use other moisture barrier, and adhesive for the surround.

Ed

 

[nealtw]

The tub surround is going over the backer board. What the surround doesn't cover (about 8 inches all around the top) will get tile. Finally!

I'm concerned mostly with any need to seal the backer or use other moisture barrier, and adhesive for the surround.

Ed

The point was that some of these surrounds are intended to go to the studs and have the backer would screw up the fit. Some are intended to have backing.

 

[EdNerd]

The point was that some of these surrounds are intended to go to the studs and have the backer would screw up the fit. Some are intended to have backing.

I don't *think* mine is a stud-fit -- but then again, I didn't know there was a difference. I'll check on that when I get home tonight.

Ed

 

[nealtw]

I don't *think* mine is a stud-fit -- but then again, I didn't know there was a difference. I'll check on that when I get home tonight.

Ed

The ones that go to the studs have screw hole around the perimeter or the top will have a flange like the top of the tub to take drywall.

 

[Snoonyb]

The tub surround is going over the backer board. What the surround doesn't cover (about 8 inches all around the top) will get tile. Finally!

I'm concerned mostly with any need to seal the backer or use other moisture barrier, and adhesive for the surround.

Ed

There should be no need to seal the backer because the panels are designed to the interlocking and waterproof.

With respect to applying the tile above and around the panels, you should use a coarse notched trowel that will give you enough build up of thinset to overcome the thickness of the panel.

 

[EdNerd]

Okay - my memory ain't what it used to be (along with a lot of other stuff!). The alcove is pretty flush on the left wall; with the wallboard gone, the concrete backer is actually about 3/8" inset.

The surround does not have screw holes around the edges, but it does have what might be a flange at the top. Photos show the rear of the back panel on the left, and the front of a side panel on the right.

Part of the concern of sealing the concrete was the possibility of condensation or other moisture building up behind the surround panels?

Ed

 

[Snoonyb]

Along with the tub surrounds, and because you are closing off the natural light and ventilation, you should also be considering an exhaust fan.

Removing the source of hot humid air will mitigate the condensation.

 

[EdNerd]

Already on the agenda.

 

[nealtw]

Close up photos of the top and bottom of the surround please.

If the plastic is seal properly moist air should never get behind it.

Are there any labels on the plastic parts that we could look up.

 

[EdNerd]

Well, darn!! I looked at the instruction book for the surround .... and it's a stud mount! I can't take it back. And there's just no reasonable way I can use it?? Except I remove all the backer board?

 

[nealtw]

The stud mount is a much better product than the glue up stuff, so I would remove the backer and start over.

And a tip of the hat to Oldog for thinking to ask that question.

 

[Snoonyb]

Well, darn!! I looked at the instruction book for the surround .... and it's a stud mount! I can't take it back. And there's just no reasonable way I can use it?? Except I remove all the backer board?

There is only one reason the you would need to remove the backer and install the product directly to the studs, and that would be it's projection from the wall surface and how that projection would affect the ability to seal it at the junction with the tub.

Fit the long wall section and the faucet end section, and if you have the area to caulk and seal it at the bottom, then use it.