What is the preferred method for installing backer board around a tub – in front of the flange or proud of it?
Asked by Kika Spierings 
3 months ago
Last Updated: September 17, 2024
Is there a general agreement on the correct way to install backer board around a tub?
Should it be placed in front of the tub flange and positioned slightly above the tub? (Either by trimming the back of the cement board or adjusting the wall)
Or should the backer board extend beyond the flange as demonstrated in the image?
I typically follow the method shown in the picture and haven’t encountered any problems.
This is indeed the right method
Make sure to follow the manufacturer’s instructions when installing. I recently installed one where the instructions specified placing the board over the tub lip and shimming the walls. The tub lip was unusually short, only about 1/2″ in length.
That’s not right, you need an uncoupling membrane between the cement board and the thin set.
Nope, simply a waterproofing membrane.
Hey , I’m with you 100%! Red guard is my top choice too.
Hey , just wanted to let you know that three coats of red guard, hydroban, or aqua seal should do the trick. I personally prefer red guard, but if it’s not available nearby, aqua seal is a good alternative. I don’t think hydroban is significantly better to justify its high cost.
Hey guys, have you tried using uncoupling membranes like red gard, aqua seal, or hydroban?
It has the potential to be effective with the right number of coats.
Red guard doesn’t work well… Professionals in Alaska don’t really approve of it.
What do you prefer? I also like aqua seal, but let’s be honest, some of it is just extra protection. I recently removed a ceramic surround and cast iron tub from 1972, and the tile was attached to sheet rock with mastic without any water damage in sight.
I just finished the initial phase of the new shower pan about 20 minutes ago.
Wedi is pretty impressive. Laticrete seemed unnecessary as you mentioned because the board is already waterproof. Having to paint the stuff on… But at the same time, it’s a good precaution. With heavier tiles and larger styles, it could potentially increase sheer strength. Denshield used to be great until the paper failed, and now I don’t know anyone who uses it.
Wedi always produces high-quality products. It’s tough to break away from the habit of making my own pans and framing my own niches due to the high cost of everything. It cuts down on material expenses and doesn’t add much to the labor once you’ve been doing it for a while.
This house was constructed in 1972 and had to be moved once to make way for a gas station. As a result, the walls are quite out of square. In the picture, you can see that I had to add studs and angle them at the top to straighten the walls. Haha.
Hey Rodney, you don’t have to create a niche yourself. Just ask the material supply shops for some cheaper brands, like knock off Wedi. You can cut in on the layout as you go, which the clients really appreciated. We subcontracted most of the work, but the prep work was done in-house. The tile guys enjoyed working on it spontaneously. The Wedi knock off even came with glass shelves, making it fail-proof.
Or use Schluter.
The waterproofing membrane seems to be missing.
That’s how I did it last time. The guy who worked on my last house used Schluter products, which come with a warranty if installed by a certified professional. The Schluter system includes a membrane that goes on top of the sheetrock, eliminating the need for backer board. I believe investing a little extra in supplies for a membrane is worth it to avoid having to redo the work in a few years.
Schluter and wedi collaborated to create a board that can be used to replace the sheet rock
According to ‘s recommendation or requirement
Looks like you’ve found the answer to your question, huh?
I tend to avoid the cleat. There was this one incident where I witnessed a tub cracking on the cleat, and that was all it took for me to steer clear.
I think using some redgard would be a good idea.
I definitely think Redgard is the best choice!
Had my fan on and window open in the bathroom, but still felt stuffy.
Like others mentioned, waterproofing is crucial. The photo you shared shows potential problems with tile durability and water leakage.
I wonder why there’s no black paper?
In my kids’ bathroom, I used tar paper on the studs and cement board near the tub edge. I filled in the gap with caulk. When we renovated it 19 years later, there was no sign of water seeping through the tile.
Start by installing the shim studs, then add the backer board all the way down to the tub (over the lip). Caulk the seam and then apply multiple coats of red guard.
Red guard didn’t work out. Are you considering the Wedi system or something similar? Laticrete is also a good option. Follow the instructions in the picture and then apply the caulk. Finally, apply the rubber paint. It doesn’t have a strong smell either.
Oh yeah, is right! Choosing wedi or Schluter is the way to go — but wedi is actually superior!
Bathtubs are becoming obsolete. People nowadays prefer showers. Filling a bathtub uses up a lot of water. A spacious walk-in shower is the ideal choice.
Ashcroft, was that what you were asking?
The person inquired about mounting the wallboard with a bathtub.
In many renovations, the bathtub is removed and a walk-in shower is installed.
Ashcroft, that’s quite a generalization. I rarely only take showers, I really enjoy my baths. I pretty much have one every day.
Ashcroft got it. So should it go in front of the tub flange or above?
Taking a break on top of
Ashcroft and a lot of parents still have their kids bathe for many years of their childhood. I recently inquired with my property manager about installing a walk-in shower, and they mentioned that I might have fewer applicants if there’s no tub for families. It really varies based on the preferences of the owner.
Ashcroft My tub is where I reside 😊
Also keep in mind the future owner if it’s not a rental. That might cause a potential buyer to walk away immediately. (In my opinion)
For a tub with a shower, you would want something like this. The one you shared is just for a tub, without a shower.
Are you suggesting it’s specifically for a tub because of the Hardibacker/cement board placement or the redgard/membrane?
Why is the wall left exposed like that? It’s going to get wet. Gotta love those landlord specials, amirite?!?!
It appears nice, but make sure to include a waterproofing layer.
Yes, on an interior wall, it would work like the example shown.
Make sure to also apply grout on the caulk line at the bottom. Remember, caulk is meant to fix small defects that appear in the grout over time.
According to , every plain change should be caulked with a color that matches. This includes the corners and around the tub.
For plumbing applications, recommends using white or clear caulking – other colors are not guaranteed to be waterproof in the long term. Even then, it might need to be recaulked within a year and a half, especially if the owner uses CLR, which can remove paint, to clean it.
If those tiles are actually real, they are grouted to the fiberglass board and tub lip. FRP is a whole different situation.
Remember, that small gap between the tile and the tub should never be filled with grout. Over time, grout will break apart. It’s best to use caulk instead. Caulk can move and flex when the tub is filled with water and people, preventing any damage.