Installing cement backerboard is one of the more popular choices for a shower wall substrate. Cement backerboards include Hardiebacker, Durock, Fiberboard, wonderboard, and similar products. These materials bridge the gap between expense and effectiveness. When installed properly they will give you many, many years of durable shower construction.
The advantage of cement backerboards is that, while not waterproof, they are dimensionally stable when wet. That just means that when they get wet they do not swell up. Any swelling behind tile is a bad thing. It will lead to cracking grout, tile, and all sorts of bad things.
Waterproofing your studs
To install the backerboard you must have a vapor barrier between it and the wooden wall studs. While the backerboard will not swell when wet, your wall studs will. You must prevent any moisture from reaching them. The preferred material for a vapor barrier would be 4 mil or thicker plastic sheeting which can be purchased at places like Home Depot or any hardware store. You can also use tar paper or roofing paper, the thick black paper used under shingles. Although I personally do not use that, it is an acceptable barrier.
Starting with your bare wall studs on your shower walls simply take your plastic sheeting and staple it to the wall studs completely covering the entire surface which will be inside your shower. You can also use silicone instead of staples to adhere it to the studs. Make sure you overlap all the edges. Just hang it all up there like you’re hanging wallpaper. You want it covering the framing enough that if you were to spray the walls with a hose the wall studs and framing would not get wet.
At the bottom of the barrier you will want it to overlap on the shower side of the tub or shower base. That is you want it so that any water that runs down the plastic sheeting will roll off into the tub rather than behind the tub. Overlap the lip of the tub or base and silicone the back of the barrier to keep it in place.
Installing the backerboard
Now for the backerboard. Lay out your backerboards for the best fit on the walls. They can go up vertically or horizontally, it makes no difference. With a regular tub surround with a five foot back wall it is usually easier to use two horizontal sheets along the back wall and one vertical on each of the sides. (This assumes 3 X 5 foot backerboard sheets.)
All backerboards are cut by scoring and snapping. You do not need a saw for them. While there are special scoring tools specifically for this you can easily do it with a regular utility knife. While all these backerboards are essentially identical in their effectiveness as a substrate, some are more easily cut. Durock, in my opinion, is the most difficult. I personally prefer hardiebacker or fiberboard. Make sure you check the website for whichever you choose for specific instructions.
To fasten the backerboard to the framing you have a couple of choices. A lot of professionals simply use galvanized roofing nails. While this is perfectly acceptable, I prefer screws over nails when possible. Hardi makes specific screws for their backerboard which can also be used for all backerboards. These are manufactured with ribs beneath the head of the screw which help it cut into the backerboard and countersink so the head is flush. If your local big box or hardware store carries them, they will be in the tile section. You can also use just about any type of corrosion resistant screw. Anything that can be used for an outside deck can be used for your backerboard.
Fasten your backerboard to your shower framing with a screw or nail about every 8 – 12 inches. I would also suggest using a straight-edge along your wall while doing this so that you can shim out any areas where the wall studs may not be straight. The flatter your backerboard is installed, the easier your tile installation will be. Take your time, the beer isn’t going anywhere.
Allow for movement!
You do not want to butt the backerboards against one another. You need to leave a small gap at every change of plane. That includes corners, walls to ceilings, and walls to tubs or floors. There needs to be room for expansion and contraction.
Wood moves – always. It’s just a fact of life. The secret to dealing with the movement is to ensure the movement will not interfere with the tile. Leaving this small gap will allow for movement of the sheets enough so that they do not force against one another and push out. While the backerboard itself is very stable, you are still attaching it to wood.
If you have a tub or shower base you will also want to stop the backerboard about 1/8 inch above the lip. You do not want to run the board over the edge of the lip because it will cause the backerboard to bow out and your wall will not be flat. It will also allow the tub or shower base to move a bit – it’s attached to the wooden studs as well. Tubs also move when they are filled with water. You need to allow for that movement.
I usually leave about a 1/16 to 1/8 inch gap between the sheets of backerboard. This allows for thinset to lock into the entire thickness of your backerboard when you tape and mud your seams. We’ll cover that part in a minute.
Don’t allow for movement! (Confused yet?)
If your shower framing is such that you cannot place the edges of all the backerboards directly over a stud you will need to add more studs. You may do this with regular 2 X 4’s screwed to the present framing vertically or horizontally as needed. You must make sure that every edge of the backerboard is supported so if the wall is pushed or leaned on in that spot it does not move. You want solid walls.
Final step
The last thing you must do is mud and tape your seams. Similar to regular drywall all of your in-plane joints must be taped. To do this you just use regular thinset and alkali-resistant fiberglass mesh tape. You can find the tape in the tile section – it’s similar to regular fiberglass drywall tape, but it specifically manufactured to be alkali resistant. Make sure it is alkali-resistant because your thinset contains alkali which will gradually erode regular tape thus defeating the purpose.
There are two ways to address the corners. The industry standard, and the way you should do it, is to tape and mud the corner joint as well. Most backerboard manufacturers recommend this, as do the handbook standards. I only do that about half the time – I’m a rebel like that. 
*The other half of the time I only tape and mud the in-plane joints – the gaps in the same wall, not the corners. With the corners I fill the gap with silicone. I do this to allow the different planes of the walls to move in different directions, which they will do whether you like it or not. Allowing this movement in the substrate compensates for excess stress in certain applications. This is something that I do, it is not industry standard and you will likely not find anyone else recommending doing this. So when you get the conflicting information about this – that’s why. 
Fill all the gaps in your seams with thinset (you left gaps there, right?) then embed the tape into it. Then go over the tape with more thinset to smooth everything out. This will lock everything together and give you a continuous, solid substrate for your tile. That’s what you’re looking for.
When properly installed cement backerboards will create a rock solid, extremely durable substrate for your tile installation. Taking time and care to solidify what is behind or beneath your tile is the only way to guarantee a lasting installation. Your tile is only as durable as what it is installed upon.
As always if you have any questions at all please feel free to leave a comment.
Need More Information?
I now have manuals describing the complete process for you from bare wall studs all the way up to a completely waterproof shower substrate for your tile. If you are tiling your walls and floor you can find that one here: Waterproof shower floor and wall manual.
If you have a tub or pre-formed shower base and are only tiling the walls you can find that one here: Waterproof shower walls manual.
Hi, I had a relatively inexperienced by ethusiastic tile setter put in a new shower in my master bath. Had very limited funds for the project. He put in a vinyl membrane, said that it is better to not use plastic on the studs prior to installing the hardibacker board. When he put up the hardibacker, he put it over the vinyl liner, which made the bottoms flare out. He said it was no problem, that the thinset can be used to compensate. But when he put up the tile, he did one wall correctly and then decided that a thicker thinset was too hard to deal with, and he just followed the contour of the hardiebacker. I have three full walls and a half wall. The two that can be seen in sideview from inside the bathroom now bow inwards by 1/2 to 3/4″. Would you say that this is just part of tile setting, or did I get someone who has no clue? Some friends have seen his work and don’t notice the bowing, but I do. I’m contemplating tearing the tile off of the two walls and redoing myself. Any advice for this first-time bathroom remodeler?
Hi Larissa,
The only aspect of tile setting which you should be concerned with, in this application, would be the end product. The bottom line is the end product is flawed and incorrect. If it is bowed at the bottom, does not have a barrier behind the backer, and it is not compensated for then it is simply incorrect.
Roger,
I tore out my old tub, and installing a new walk in shower. I’ve poured in the mud bed, and the plastic membrane. Now should I install the vapor barrier and hardibacker or should I put in the final 1 1/2″ of mud bed. Also when installing the vapor barrier and hardibacker, what is the dimension that I need for a gap between the shower base and the hardibacker?
Thanks,
Tom
Hey Tom,
You can do it either way. I will usually install the walls first then the mud, but it can be either. If you want a gap there it should be 1/4″ or so, or you can embed it into the mud. Some guys don’t do that – I’m not one of them.
Roger,
If you’ve already answered this, I missed it. So here goes… I have one outside corner in my shower installation where HardieBacker meets drywall on a 90 degree angle. Normally, you would use a metal or plastic corner cap and mud the cap with joint compound to finish the corner. I’m trying to envisage how this is going to turn out so I can prep it correctly.
How would you finish this outside corner? Should I use a corner cap set with thinset? Should I wrap the tile around the corner using bullnose to finish it off? I’m confused on the best way to accomplish this. Please help!
Hey Mike,
I normally use the plastic caps and finish it off as normal. Unless it is inside the shower itself you can use regular wall mud. Just run bullnose out as far as you want.
So if one side of the corner cap touches drywall, use joint compound there but on the other side where it touches HardieBacker, use thinset there? Or are you referring to a different type of cap?
In my bathroom, the Hardie (and tile) will come out all the way to where it joins with the drywall on that outside corner. Hopefully this is clear….
You can either use drywall mud on both sides or thinset on both sides. You can mix it, but no real reason to. Thinset, once cured, can be sanded and finished just like drywall mud, it’s just a bit tougher. If the hardibacker side is not actually IN the shower (behind the door or curtain), drywall mud will be fine.
The Hardie is actually in the shower but it comes all the way out to the corner. The drywall is not in the shower. Sounds like thinset is the best option for me to finish this outside corner. I’ll just do a good job of not leaving a lot of mud behind to have to sand.
Thanks for your replies… appreciate the great advice.
Hi Roger, I’m taking out an old surround and putting in a new base and then planning on durocking all around. (it’s a small 32″ x 32″ space). I was thinking of doing a built-in niche or two between the studs. I’ve seen pre-fab ones for sale but I was wondering if I could do it with cement board. My concern is keeping the studs dry on those insets. Can I just redgard that area and vapor shield the whole enclosure?
Hey BT,
Yes, as long as you silicone the back of the vapor barrier around the perimeter of the niche when you cut it out.
Nice of you to take the time to answer these questions of ours. I need to cut several thin (2 3/4″) pieces of backerboard to install behind a backsplash in my kitchen and I’m wondering if I need to cut them with a skill saw for accuracy re: the break or if scoring them with a utility knife will suffice.
Hey Valerie,
As long as you take your time you can score and snap it. You don’t want to use a skill saw. The blade won’t last long and it’ll be a cloud of dust through which you cannot see!
When I install backer board within 1/16 inch above a shower flange, I will have a gap of about 1 inch. I am going to install 1″x1″ glass tile on the backer board. What do I need to do about this gap to fasten the glass?
Hey Bill,
If you are installing tile that small you need to shim out your wall studs so the backer will sit over the face of the flange. It doesn’t stop 1/16″ above the flange, it stops 1/16″ above the horizontal arm of the tub or base.
Hey Roger,
I’ve installed my backer board just above the top lip of my shower pan. But I’m uncertain on how the tile will lay on the bottom of the backer board. Should it stop flush with the bottom of the board or should it hang below the board actually making contact with the shower base. Thanks for any light you can shed on this!
Hey Rick,
It should hang down below the edge of the board to about 1/16″ above the horizontal arm of the tub.
Hi Roger.
Great website. You explain things so well and give awesome rationales (another big word for your list
) that really help me understand what I am doing and, more importantly, why I am doing it. I do have one question however and I hope you haven’t been asked it a million times but if you have I am sorry. When installing backerboard over a waterproof membrane such as 6 mil plastic sheeting or 15# roofing felt there are multiple screw holes that go into the studs and through the waterproofing membrane that seem to be a good avenue for water penetration into the studs. Is it necessary to waterproof those holes with say a 100% silicone caulk or is that just overkill? Thanks for your help.
Hey Brian,
I really need to write that post.
As you screw in your fasteners the plastic ‘puckers’ around the screw. This pucker around the screw creates a dam which water runs around rather than into as it runs down the wall. No need to seal them.
I’ll get that post written, I have diagrams and everything!
Do I need to do anything special with the traditional liner around my shower valve? I just cut a hole and fit it snuggly around the valve. Anything else? Thx.
You should place a bead of silicone around the perimeter of your cutout. When you install your tile do this: Waterproofing valve cutouts.
Sorry. In the last question I asked you, “capadible” was meant to say “compatible”.
I used hardie backer cement board for my tub enclosure and used durabond 90 for taping the joints. Is this acceptable or do I need to prime the joints as I am not certain it is capadible with 66 flex light tile adhesive.
Thanks
Hey Mark,
The problem is not the compatibility with the mortar, it will bond fine. The problem is you have regular drywall compound on your substrate in a wet area. It needs to be either waterproofed or removed and replaced with a thinset mortar or other water-stable bond coat. Joint compound will eventually fail if continuously exposed to water.
I have poured a concrete shower base on a wooden platform and troweled it to slop to the drain and am going to tile the shower walls. What is my next step? Do I lay the rubber membrane down over the adjustable drain and nail it up the studs 8″ then pour the concrete floor. Then install the vapor barrier and backer board? Or do I first install the vapor barrier on the studs, install backer board before I install the rubber membrane and pour the concrete floor up to the backer board? This is a basement shower being built so the upstairs shower can be remodeled eventually.
Hey Joe,
If you made your shower floor with straight cement your next step is to tear it out and start over building it correctly with deck mud. The entire shower floor, including the membrane and top mud deck, should be in before moving on to the walls.
Hey Roger! Thank you for all your help on this. We have placed our new Kohler tub and have one issue. The flange on the tub is 1/2″ wide. I have read the directions and it says to extend the backerboard over the flange within 1/4″ of tub lip. If we fur out our backerboard to go over the flange, it will sit out will not be even with the walls it has to meet (by almost 1/2″ in fact). My husband wants to just run the backerboard down to the flange, put some silicone between the backer and the flange gao and then put our tile down over the flange within 1/16″ of the tub. I am not sure if this is right, but I really don’t want my walls to be uneven. I am torn between what the instructions say to do and what he wants to do. His way will make the walls even with each other. The directions way, we would have to do something to cover our uneven walls. What to do?
Hey Beth,
He’s right but (!) whatever waterproofing you are using (you did not mention any) needs to be sealed to the flange so water that gets behind the tile will run down into the tub. Other than that there’s no reason at all not to do that. I do it all the time.
We are using redguard. So should we use someting else here. Hubby just wants to silicine between the hardiebacker and flange.
Redgard is fine. Silicone between there and paint the redgard over it down onto the flange.
I am planning the layout of my backerboard. I am using Durock, 5X8, because the price was right – free, someone gave it to me. My shower is 61 1/2 inches wide. My question – How wide can the gap be in the corner? The board is 60 inches wide and if I lay the side walls first, I will have a 1/2 left over. I can split this to be a 1/4 inch on each side. Is 1/4 okay? If yes, do I fill it with silicone or do I need to fill it with a backer rod before the silicone? If no, what is the maximum width allowed in the corner? Of course, any suggestions would be welcomed!
Thank you
Hey Heidi,
1/4″ is a bit large, but it’ll work if you tape and mud the corners.
Do I fill with silicone or backer rod first before the tape and mud? One of my free Durock sheets is 5/8, should I use this on one side wall?
Just fill it with thinset and tape over it, then float it out with more thinset. You can use the larger sheet wherever it’ll work, one of the side walls should work fine.
Hi Roger,
I’m remodeling one of our bathrooms and will be tiling the tub surround. The back wall of the tub is an exterior wall, would you recommend that I tape and mud the corners of the durock or use silicone as you mentioned in the article. Thanks for the helpful website.
I would tape and mud them.
Hi Roger,
I have the same situation with the back of the tub surround being an exterior wall. I was going to silicone the corners as it seems that is what you most often recommend. Is the fact that it is an exterior wall make a difference and make tape and mud a better choice? And for my shower with no exterior walls, would silicone be a better choice?
Thanks, Linda
Hi Linda,
No, the fact that standards dictate that it should be taped and mudded make it a better choice.
I have recommended silicone there – a lot – but I’m beginning to get away from that. Either way works, in my experience, but it may not work in all climates. So I recommend taping and mudding all corners and am slowly moving towards that.
I know, I’ve confused the issue, I’m an unintentional jackass sometimes…
I have asked a similar question on another page. One corner of the backerboard is a concrete block exterior wall and one corner is an interior wall. From your comments here, I do tape and mud the corners. Do you agree?
I am always in some state of confusion so confusing the issue is fine with me!
I recommend taping and mudding all corners.
Roger,
One more question on this topic – how about the gaps between the Hardibacker in a niche and the inside corners of a window seal – silicone or mud & tape? I’m using Redguard for waterproofing.
Linda
Tape and mud them.
Guess I do have one more question on this topic. We are putting the Hardi up to the ceiling in the shower over tub as we are tiling up to the ceiling, but we are not tiling the ceiling. My question is about the small gap between the top of the Hardi and the ceiling – if I tape and mud it, half the tape would end up on the ceiling and show after it is tiled. I’ve come up with 4 options so far: put most of the tape on the wall and put just a small amount (1/4″) onto the ceiling so it would be covered by the tile and then mud the gap; just mud the gap (no tape); calk the gap: or just leave the gap empty. Your thoughts?
Tape and mud it. I don’t know how you’re finishing the ceiling but it can be finished just like drywall. Feather out wall mud to cover the tape.
Unfortunately the ceiling is already finished/textured -this is a remodel. I was wondering if I could get away with calking that gap. I will waterproof with redguard. I was wondering if it was like when laying hardi on a floor – how the gap between the hardi and the wall is left empty. I was hoping the tape and mud wasn’t necessary?
While it’s best to tape and mud it, you can caulk it at the ceiling.
Hi Roger,
I am faced with replacing my shower walls. The orig. walls used standard sheetrock under tile. I realized this after a couple tiles collapsed while cleaning! I have read multiple suggestions not to use greenboard under shower surround panels, which I plan to replace the tile with, but to use concrete backerboard instead. A plumber who does remodeling informed me this would not work as shower surround panels and greenboard, which he would use, create a friction & better adhesion. Please clear up the confusion!
Hi Liz,
Never heard of that, ever. The best place to get an answer to that question would be the panel manufacturer. I replace panels with tile, not the other way around.
I will say that anything that creates friction against greenboard will create a hell of a lot more against cement backerboard. The panel manufacturer will be the only one that can reliably answer that for you.
hi rogers,
we are putting in shower and bought a shower, sliding door and backerboard to put the tiles on. my question is : would it be best to use a wonderboad instead of the backer board?
Hi Lisa,
Wonderboard is simply the brand name of a certain backer board. Backer board is a general term, wonderboard, durock and such are brand names of backerboards. It’s like kleenex being the brand name of a tissue, there are others, but they are all essentially the same thing.
I am taking the old tub and shower surround out and giving my old football knees a break by building my own wide shower with a small lip to step over.
I will square the walls, maybe build them out to add insulation, and am wondering if I should build my own pan or buy one. I think building will be cheaper and fit my space better. I plan on Durok and Green Seal or Red Guard instead of a rolled membrane. Do I just use Durok on the lip and treat it like the regular wall?
Hey Matt,
If you are using a topical membrane as you’ve described then yes, you just treat the curb like any other wall in the shower. Build it and waterproof it the same way.
Roger,
I am doing a hybrid shower with a 42″ x 42″ Kerdi pan and redgard over permabase walls. Couple of questions for ya, oh elfin one.
I am using river rock for the floor tile so I am increasing my slope to almost 1/2″ per foot. I will use the wall sill plate as my pre-slope final height of 1 1/2″. How far down the wall do I install the permabase?? Does it come down to just shy of the pre-slope mud then silicone the gap??
Also, do I silicone the gaps in the curb change of plane for the Permabase install there?
I’m thinking it makes sense to kerdi the pan & wall base then redgard the walls (overlapping the kerdi with the redgoo) but in case the dogs spontaneously combust, can I use a fire extinguisher rated for just AC fires or do I need one rated for ABC fires?? (I may have one of those on my boat….. )
Last one. Any “fire hazard” using drywall mesh embedded in redgard as opposed to alkali tape??
Many thanks
Hey Chris,
You have a few confusing points in your question there. First you mention a pre-slope, if you’re doing a kerdi pan it is just a single slope. Secondly you mention siliconing gaps at the curb, there shouldn’t be any gaps there. The type of shower you are building is actually a bit easier, you’re overthinking it.
Install the permabase, almost all the way to the floor. Build your curb and cover it with permabase. Then install your mud bed, the 1 1/2″ height at the walls is fine (although you’ll need to mark that since you will be covering the sill plates). Then kerdi the floor and up over the curb, then install your redgard overlapping the kerdi. That’s it.
Drink copious amounts of your preferred adult beverage.
Oh, about the drywall tape. Alkali will eat through regular drywall mesh. You need the alkali resistant to prevent Fido Flames. (ABC, btw…)
Roger that, Roger! But I’m SHOCKED that I should butt the three planes of CBU that go around the curb…. I’d think that the curb gets plenty movement??
Where did I say to butt the cbu? Never butt anything in a shower, except your butt when it’s finished. Always leave at least a 1/16″ gap between materials. There is movement everywhere, you need to compensate for it.
Thank you so much. We are still very much in the planning stages and are very grateful for your advice. We will definitely install the furring studs if you think it best, I just had this whacky idea and didn’t know what the consequences would be. I’m glad I found you to get some advice.
Thanks
Darla
Roger,
We want to install one of those endless pools in our home, but can’t afford it unless we do most of the construction ourselves…so this isn’t a bathroom – exactly, but definitely a room with high humidity and moisture. The pool will be up against one wall in the room. Should we use cement board or will green board be okay? We removed some drywall in the room to see what we were dealing with and the wall we are putting the pool against has cinder block behind it. Can I use construction adhesive and attach the backer board directly to the cinder block? As you can imagine we need every square inch we can gain in this room – even the smallest pool has a big footprint. Thanks!
Hi Darla,
If you plan on building any type of pool then lose the word ‘greenboard’ from your vocabulary.
Cement board will work fine, but I’m a bit concerned that you’ve not made one mention of what type of waterproofing you’re planning. What is your waterproofing method?
Construction adhesive will not do what you want it to do. If you do not want to install furring studs against the cinder block for the backer than installing the backer directly to the blocks with thinset will be a better alternative than construction adhesive. I would STRONGLY recommend furring studs to frame out a wall for the backer, though. It will last long-term. While thinset is a better alternative then construction adhesive, it may not last long-term in that application. Cinder block walls can move a LOT, the bond of the thinset may not last. If you are using a topical waterproofing membrane (best) then you can also use tapcons into the cinder blocks, that’s a better option than thinset.
Just found your site and am learning a lot. I want to add tile in the ~2 ft space above the existing pre-fab shower walls and to the ceiling above the shower. Those regions are currently just painted walls. I don’t know what type sheetrock was used (house is almost 20 years old) but I presume it is appropriate since there have been no issues with moisture. My question is do I need to remove the existing sheetrock and use backerboard for the tile or can I leave the existing sheetrock and tile over it. Any thoughts would be appreciated! Thanks.
Hi Rick,
You can use thinset and install the tile over what you currently have. No need to replace it with backerboard up that high.
Thanks! Should I seal the sheetrock with something (and if so what do you recommend) or can I just tile over the painted sheetrock? Also, at one point along the ceiling the tape on the joint is separating from the ceiling slightly. Do I need to use anything special to repair that before sealing or thinsetting?
Thanks for all the help.
You can go right over the painted drywall. You may want to rough it up a bit with sandpaper to take the sheen off, you’ll get a better grab on the thinset. No need for anything special for that repair.
Hello Roger,
I have kind of a strange problem. I’m remodeling my bathroom and I had some help install the tub and backer board. The problem is the backer board wasn’t installed down over the lip of the tub; in most places, i think i can just hang the tiles down the last half inch and fill the void behind with mortar but on one side of the tub the tub flange extends past the backer board by at least a quarter inch. Is there any way to build up the backer edge before installing tile so I can get the tile down to the tub or do I need to remove the backer and reinstall it correctly with shims?
Thank you,
Alex
Hey Alex,
the problem with building up the backer edge is that it won’t be flush with the plane on the rest of the wall. About the only way to do it is to shim out the backerboard to the proper depth. Do not use thinset behind that 1/2″, it will crack out. The tile can just hang over that space without anything behind it.
Hi Roger,
Thanks so much for providing all this advice. We had grout failure in our shower that rotted through the studs and everything had to be replaced. The main wall of the shower abuts the exterior of the house. There is a moisture barrier/wrap between the siding and the studs. Our contractor then put insulation between the studs and mounted DuRock. Is that an ok way to do it or should there have been another moisture barrier between the studs and the DuRock? Should we put RedGard on the DuRock or would that create a “mold sandwich”?
On a separate note, the DuRock did not reach the top 9 inches of the wall, so the contractor used a spare piece of greenboard there, saying that the water would never get up that high. Is that okay?
Thanks so much.
Hi Casey,
First – a grout failure never causes a shower failure, leak, rotting or mold. A construction failure and improper (or non-existent) waterproofing does. You need some sort of water barrier in that shower or you’re gonna end up with what you had before. The barrier on the outside of the house doesn’t count.
You can either remove the durock and install a barrier behind it or use a topical membrane like redgard over it.
Yes, the top nine inches is fine with greenboard.
Hi,
I am doing a master bath remodel. I am using a KBRS tileable shower pan. In the instructions it says to leave 1/4″ around the vertical flange and the wall studs… “free float”. So I have it use furring strips on my studs to do this. So would I do 1/4″ strips all the way up my wall studs to where the backerboard stops which will be at 7′. My drywall thickness is 1/2″ but there are furring strips ie cardboard on the existing studs so I have inconsistent thicknesses of drywall that I have to somehow account for:( any help would be much appreciated!
Hi Corrinn,
You can do one of two things:
Shim all the wall boards out to that depth so you have a flat plane all the way up the wall. Or you can place the shower pan flange against the wall studs like every other shower pan and tub on the planet. I absolutely cannot stand KBRS – this suggestion is one of the reasons why. There is absolutely no reason (and I’ve called, they can’t give me a reason either!) to have the base 1/4″ away from the wall studs. It’s ridiculous. It’s a pain in the ass. And it isn’t necessary.
I would choose option #2.