I get a LOT of questions about how to build and waterproof a bench in your shower. I’ll touch on the easiest method here, but there are a couple of different methods you can use.
I will describe simple framing of a bench with your substrate over it. You can also use after-market, pre-fabricated benches. Better Benches (google it) attach directly to your wall substrate, the top gets filled with deck mud and it gets tile. There are also several different Styrofoam products available from companies like Schluter and Laticrete. They are made from the same type of foam used for their shower bases. Although they are ‘foam’, once tiled they are more than sturdy enough to support your tile.
While you ‘can’ build a bench in your shower after you form the shower floor with deck mud, it’s always easier to make your bench first. Your floor substrate is flat, your shower floor (should be) sloped. It’s difficult to build a level bench on a sloped floor.
But you can do it if you wanna.
Rectangular frame for shower bench
As I said typed, the easiest way is to simply frame a bench and cover it with your substrate. The waterproofing is ALWAYS easier if you use a topical membrane. Either a liquid like Hydroban or redgard, a sheet membrane such as kerdi, or a topical board like kerdi-board.
If you are using traditional waterproofing in your shower with a membrane behind your substrate, I will cover that in a little bit.
Triangular frame for shower bench
The rules for benches and concrete are the same as curbs and concrete. If you are building on top of concrete rather than wood use bricks (cinder blocks) to build your bench. Just stack them up to the height you need and bond them to one another with regular thinset.
There is no hard and fast rule to framing your bench. Just build a square frame box out of 2×4’s and put your substrate (cement board, or drywall if you’re using kerdi) around it. It’s really that easy. If you want to build a corner bench then build a triangular frame, or arced frame, to place in the corner.
Arced shower bench
The first couple of photos are small bench frames I made for showers. The top one is only 2 ½ feet wide by 1 foot deep. It is 22” high. I normally build them 21 or 22 inches high, but that isn’t required either. The other two are corner benches.
Slope the top of your bench!
Be sure you slope the top of your bench ¼” per foot toward the front of the bench! Water needs to drain off of it rather than collecting in the back of it.
So how do you decide how high to build it? Ask the woman in the house. I’ll let you guys in on a little secret. The bench she wants you to build in the shower? She’s not going to sit on it. She wants it so she can shave her legs. Really. Ask her.
So it really depends on how tall she is and where the comfortable height is for her. Ask her. Starting to see a theme here?
It usually looks better if you build the bench around the size of your tile. For instance, if you have 12” tiles, don’t build your bench 25” high because you’ll have a 1” strip at the bottom. It’s not imperative to get it exactly the size you need it, but keep the tile size in mind while building it.
Kerdi waterproofed bench
Your bench doesn’t need to be huge. It can even be just a little triangle in the corner, like the one above. It’s for a foot, not a butt.
Once you get it framed and covered with your substrate just waterproof it with your choice of topical membrane. This one is kerdi.
Kerdi-board waterproofed bench
And this one is kerdi-board.
I don’t have any photos of a cinder block bench, but it’s just as easy to build one. Stack your cinder blocks up however high you want them, minus 2”, with the open holes vertically. Once you get them stacked up place cinder block ‘caps’ on top. The caps are solid 8 x 16 x 2 inch bricks that fit right over the top of the cinder blocks to give you a solid top.
Once again, make sure the top of your bench, in this case the caps, are sloped ¼” per foot toward the front of the bench.
Once the thinset cures just cover your cinder block bench with your topical waterproofing.
Now, if you are using a traditional waterproofing method it’s a bit different. You need to build your bench BEFORE you put your membrane up on the walls. I really don’t recommend this method, it’s a pain and if one thing is done incorrectly then your bench may leak. But it can be done.
And I don’t have pictures of that either, because I don’t build them like that anymore. But I will answer any questions you may have about them if you leave a comment below.
Frame your bench against your wall framing and put a solid piece of backerboard on the top, making sure it’s sloped. When you run your membrane down the walls, run it down and over the bench, down to the floor overlapping the front of the floor membrane.
Your regular substrate will be installed on the face of the bench (and the sides, should you have them) but you need to make the top of them 1” higher than the frame. The front of your bench is treated as any of the walls. The floor membrane runs up it and the wall membrane overlaps that with the substrate screwed to the front.
Your substrate will stick up 1” over the top of the frame to form a ‘box’ around the top of your bench. Your seat, the top of the bench, is formed from deck mud. The extra 1” will give you an edge for your top and the top is simply shaved flush with the top of the substrate. Tile is bonded directly to the cured deck mud on top of your bench.
You cannot use your wall substrate on top of your bench! It will drive fasteners through the membrane on a horizontal surface – it will create a problem. You need to use deck mud.
If you are going over concrete and using the traditional method you need to build and waterproof your entire shower, then build your bench INSIDE the shower, so the waterproofing is surrounding your bench. There is no waterproofing on the bench itself, it’s all under and around the bench.
If you build your bench inside the shower it needs to be built out of cinder blocks. You cannot frame a bench inside your shower using wood unless you are using a fully topical waterproofing method in your shower.
This is why it’s better, and easier, to use a topical membrane of some sort for your bench. It is, in my opinion, the only way to build a bench. If you want a bench, spend the money for some sort of topical membrane for it.
If you have a bench you cannot use a topical membrane only on the bench with traditional membrane on the walls. There is no way to channel the water from your membrane behind your wall substrate, over the membrane on the bench, then into the floor membrane (unless your bench is built inside your waterproofed shower).
As I said typed, there are many ways to build a bench for your shower. This is the easiest. I realize some of this may be confusing due to different types of waterproofing and lack of pictures. I only build my benches with topical waterproofing, so I just don’t have them.
The important keys are to ensure that your waterproofing on the wall is continuous from the wall, over the top of the bench, and down the face of it, and to ensure that the top of the bench is sloped toward the drain. Anything wooden needs to have waterproofing OVER it, and the waterproofing needs to tie into both the floor and the wall membranes.
I’m absolutely positive there will be questions, so leave a comment in the comment section below and I’ll answer it as best I can. Not necessarily about this method, either, if you have a question about any of the pre-formed benches, better benches, etc., I’ve used most of them and can answer those as well.
Below are a bunch of photos of different benches. Look through them first, you may discover an answer in there. You can click on any of them for a larger version.
Great Site!!
Question about corner seat.
I have framed out the 60″ x 42″ shower. Have yet to mud the pan.
I placed doubled 2×6 blocking between the studs in one corner at 15″ –
20 1/2″ high.
My intent is to use aluminum L solid angle ( http://www.amazon.com/National-Aluminum-Solid-Angle/dp/B004C1W90M ) after wall tile is placed, attaching the 24″ L angle on front and side wall corner by drilling thru the 3/8 porcelain tile, backer and into the blocking and studs to lag in the L angle.
Then, the plan is for 1″ High Density Polyethylene for the seat…
( http://www.usplastic.com/catalog/item.aspx?itemid=31842&catid=705 )
Or, could be Teak slats or what ever to be attached to the L angle.
My Question, is this an OK idea? I’ve certainly done this for shelving in corners and it’s been very sturdy. I also plan this kind of attachment for a corner soap and shampoo shelves. (but not with the huge Aluminum L’s)
Thanks for your thoughts,
ChaZ
Hi Chaz,
It will work just fine provided you seal between the aluminum and whatever waterproofing method you’re using, and seal the penetrations through your substrate.
I am planning on building a custom shower with a bench using the traditional waterproofing method. I just wanted to make sure I understand completely from what I have been reading before making a mistake. The shower will be built on a plywood sub floor and I plan on building the pan and the walls as if there were no bench. I then would like to build a bench out of cinder blocks and place them on the pan. I believe you said it can be done this way since the shower itself is waterproofed and there would be no need to waterproof the bench. Am I correct in my line of thinking? Thanks!
Hi Kyle,
Yes, that is correct. I still prefer to waterproof the surface of the cinder blocks just to keep water from inside the bench, but it’s not necessary, water won’t hurt anything inside there.
Thanks. As a small follow up question. I have seen and read about shower pan pitch guides that can be used to ensure a proper pitch of the pan. Have you had any experience with these?
Yes, they work well for diy’ers to get a proper slope (provided they are used correctly, of course).
Hi
I have a metal floating type bench that I will put in. Will span 30″ or so only and have reinforced angle I may or not use though not required of course. With the end walls being two thicknesses of 1/2″ Durock (it was a have-to thing) and the back secured thru Durock over heavy square metal ‘studs’over cement block wall,,, should any further be done to secure it?
Also with a grab bar/shelf put in on the double Durock wall, will that pass any code? I could put more metal stud behind it to screw it to. That will be through tile, thinset, two layers of Durock as is.
The bench will be fine with that through the tile and durock, as will the grab bar and shelf. It will be more than sturdy enough to pass any code of which I am aware.
Had in mind to build bench and rebuild curb with cement bricks as the base. Can’t find that size of them. I’ll not give up and wince at the thought of making with any wood.
Bricks can be cut with a wet saw or grinder.
Hi there .. I’m building a bench in a custom shower .. do you need to do the top of the bench with something like Ditra it will plywood do? If plywood is ok does it need to be doubled up?
Thanks in advance
Hi Luc,
It depends on your waterproofing method. If you are using a topical waterproofing method like kerdi or hydroban then you can make it out of one layer of plywood with a layer of backerboard over it (your waterproofing membrane needs to be backerboard, they should not be bonded directly to plywood – too much movement). If you are using the traditional method then you can use a single layer of plywood with your barrier over it then build up the top with deck mud.
How much would you charge someone to add a 17″ bench after the shower is already complete?
1.) using the better bench
2.) cinder block and tiling all the way to the floor solid
Thank you!
Hi Michelle,
1. A shitload of money
2. A shitload of money – doubled.
I don’t answer pricing question for several reasons: Prices vary a lot depending on where you are located, some guys just throw out numbers without any idea what is involved, some guys actually run a business and know what is involved, how much it costs them and how much they need to make, not everyone runs their business the same way. I know what my rate is for everything, I also know how much it costs me to run my business, that is reflected in my prices. My prices are also normally 25-40% higher than most. I’m an ass like that.
I have a 42 by 74 shower with a corner bench. I constructed the bench with wood before the preslope was place directly on the subfloor attaching it to the wall framing. I blocked it all around its oerimieter. I then placed the preslope with the “wall” of the bench being just like the other walls. I then placed the pan liner on the pre slope and ran it up a good 18 inches. I then ran another liner over the bench and up the wall above the bench another 18 inches. and lapping the other line a good 12 inches on the vertical bench wall. I bonded the two liners together. I then place Durock on the vertical bench wall only screwing it along the top edge with the fasteners “wet” installed with silocone. I then put a piece of Durock on the bench seat. I trapped that piece with the other wall pieces so I didn’t have to fasten through my bench liner….all fasteners are above the bottom edge of any board by at least 12 inches. Anyone think this will leak?
Hi Stu,
Don’t know about anyone else, but I don’t think it will. I really don’t like the penetrations through the liner, even at the top of the bench and with silicone. Provided it’s sloped correctly you shouldn’t have any problems with it.
Hi Roger,
His/Her shower – concrete floor – back wall cinder block – left and right wall 2×4’s with valves. I built a verticle bulk head around a vent pipe out of 2×4’s in middle of the back cinder block wall that goes from floor to ceiling and am adding a bench on the right side of it that will conect to the right wall. Is it ok to build the bench out of wood (attached to right wall and verticle bulkhead on left) and nail it to floor and lag to cinder block wall (with drop ins)? Or should I build it out of block?
Wood would be ideal for me. If it can be done, can I just ply-wood the top then backer-board on top of that? If so should I seal everything (bench, walls, ceiling, floor)?
Thanks in advance.
Hi Dave,
You can do all that, and build the bench out of wood (plywood on top with backer over it) provided you are using a topical membrane to waterproof your shower. You did not mention anything about waterproofing at all, worries me a bit.
After reading up on everything I’ve decided to go with cinder blocks for the bench since my existing floor is concrete (in my basement). I’ve read your website a few times, (thank you very much for taking the time to share your knowledge!) but I’m still a little uncertain about when is best to build and which way to waterproof the cinder block bench with the shower. Should I build the bench before the preslope? Or do I build on top of finished decking? (I’m using a waterproofing layer on top of preslope, under top decking, 12″ up the wall like you suggest.) My concern is not getting a level bench if it’s built on finished floor. How should I waterproof the bench once it’s built? Also, would it be a better idea to stud and insulate the cinder block wall then add hardiebacker? I was going to just try and lag the hardiebacker to the cinderblock wall, but I’m concerned about temperature in the bathroom. Thanks!
If using a traditional pan liner and cinder blocks you want to build the bench on top of the mud deck inside (above) the waterproof liner in the floor. Once your deck cures mix up a little more deck mud and set the first layer of cinder blocks into it until you get it level, let it cure, then just stack your blocks. You don’t need to waterproof the bench itself if it’s inside your waterproofing.
Hi Roger,
I lined my shower niches with solid pieces of marble tile and will be framing it with the marble pencil trim (I think that’s what they call it) It would look nice without grout lines where the flats butt together. What do you think about this? If no grout lines are an option, than what adhesive or sealer do you suggest?
Thanks for your time!
Hi John,
You need grout lines, if even 1/32″. Butting them will cause chipping eventually.
Roger, I plan on building a custom shower with a bench(not in a corner) and a shampoo shelf,cubby hole, or whatever people call it. First do I need a vapor barrier if I put durock over the studs and then redguard from top to bottom over the durock? Ok so now my other questions, I looked through your website and I noticed the pictures of benches you made, they sit rite on the floor. Did you build your morter shower pan to move water to the drain after installing the bench? If you do put benches directly on the floor and then put in the pan how do you keep water from getting behind the bench? I would like to build my pan complete, then install the bench on top of it, then durock over the bench then redguard everything. Would this work and not leak? I hope I have explained everything so you can understand it. Your website is very helpful but I am just a little confused about these couple of areas, Thanks for your help, Rusty
Hi Rusty,
No vapor barrier with redgard. Most were built before the floor mud was installed, they sit right on the flat floor.How would water get behind the bench? They go from the wall directly to the front of the bench, it is treated as another wall. There is no ‘behind’. Yes, you can build it like that, but you’ll be building a bench on a sloped base. It’s harder.
Hello again!
Have finally finished kerdi water proofing membrane in a 53″ x 48 ” shower (4′ x 4′ base)…very do -able for the DYIer but…time consuming your first time…anyhow…
just not sure about where to start the tiling…understand I should use largest tile pieces with as few cuts as possible and should probably start on the 53″ back wall…however…the bench….should I tile the seating surface of the seat and bring the wall tiles down on to the top of them to shed water as opposed to tiling the seat after the walls?
This is probably pretty obvious to a lot of people but…this is my first shower and I don’t want to screw it up!
Thanks Your Elfness!
Hi Jeff,
Actually, it’s not that obvious to most people. With a properly waterproofed shower it makes absolutely no difference at all which order your tile is installed. I prefer the wall tile over the bench, as you’ve described, but it’s just because I like the way it looks better than the alternative. It’s strictly an aesthetic choice.
Want to run my plan by your before proceeding any further. I am doing a traditional waterproofed mortar shower bed with a wooden bench in the back of the shower. The oatley membrane is going to run up the front blocking of the bench. The walls of the shower, along with the front and top of the bench, will have topical waterproofing with redguard over the cement board. I have seen pictures of wood benches with plywood over the whole front. If I have my 2×10 blocking, do I also need a piece of plywood or can I just put my cement board over the front of the bench frame? Thanks for the entertainment and the wealth of knowledge. If you lived closer, I would drop off some cold beverages.
Hi Jon,
Just cement board is just fine. You do want a solid substrate beneath the backer on top of the bench, but the front is just fine without it.
Hi we have a shower leak. We have a full across shower seat. Where the front of the seat meets the piece in front. Like where the front piece goes from shower seat to the shower pan. Where the top or front of seat meets this other front Under the top of the seat is a gap a space. It was never caulked by the builder. And now a problem. Should it have bee buckles right from the start. The water can run in there while sitting on seat and using the shower. Thank you
Hi Ct,
I’ve read that seven times and still can’t figure out what ‘bee buckles’ is supposed to be.
If there is a space there then it is indicative of the substrate, normally on top of the bench, getting wet and swelling. Caulk or silicone WOULD NOT have stopped that, the substrate itself needs to be waterproofed beneath the tile. Your bench is obviously built incorrectly.
Hello we built a shower and tiled it already . The shower is four foot by eight foot long. Can we add a bench after it’s been tiled? If so how do we add it?
Hi Karen,
You can add a better bench to the face of the tile. That is about the only type I would use since anything else would be impossible to tie into the waterproofing behind the tile. You can get them at Amazon.
Hey…love the site…
Question…since I am using Kerdi over the entire shower surface (floor/walls and bench, etc…)…how do I fasten a ledger to start with the second course of full 12 x 12 tile…if I use screws, I will have compromised the kerdi membrane…when I remove the ledger, do I just thinset and kerdi 5×5 patch over each hole…or what???
Thanks for your time
Hey Jeff,
With screws.
Once you remove it you can patch the holes with kerdi-fix, silicone, or a patch as you’ve described.
Doing a shower on a concrete slab and looking to use a Schluter shower kit (the thought of doing my own shower floor is too daunting). If I build the bench with cement blocks on the flat slab can I just cut the Schluter shower base? Do I need to thinset it up against the block? And then cover with Kerdi membrane?
Anything else?
Hi Derick,
Yes, cut the base around it and install the kerdi from the floor up the block.
That’s it.
Hi Roger, love your site and your books on waterproofing showers. We’re trying to choose a tile for the floor, and I read somewhere that the larger the tile, the more concerned you need to be about having the floor super level.
Is this true? I really like the large format subway tile that’s popular right now, 12×24 installed in a brick pattern. Are these tiles more likely to crack?
Thanks!
Hey Devin,
It is true, but not to keep them from cracking. With large format tiles you need a flatter floor because each tile covers more area, if your floor is wavy you can not get a good, consistent bond from tile to tile. And it needs to be super flat (1/8″ in 10 feet), not super level.
Or if brave enough with plumbing, slope floor to a trough drain? Then can use large tile, correct?
Yes, with a flat slope you can use any sized tile you like.
Roger –
Great site with lots of info!
I am replacing a bathtub/shower combo with a shower only. The new shower will be 3 X 5 with a curb the entire 5′ length. I built a bench in the back corner that is 17″ tall (I went with the cinderblock / mud inside the pan method). I am using 12″ tiles on the walls from floor to celing (I’m 6’5 so I moved shower head to 7′ from floor. Celing is 8′). I can’t decide how I want the layout. Which would be more correct / look better???
Option 1:
Start with course of 12″ tiles cut 5″ tall at the bottom followed by full 12 X 12 tile in second course so the 2nd grout line matches the grout line at the top of the bench.
This layout will end up with a 5″ tall course at the bottom and a 4 – 5″ tall course at the top.
Option 2:
Use 2 courses of full 12 X 12 tiles, notching the corner tile to fit the bench.
This will make all courses full tile except the top course which will be about 8″ tall.
No matter what, the vertical grout line will not line up with the bench because I am doing a built in and the stuf placement wouldn’t allow me to match both the bench and the built in. I am choosing to make the side of the built in the vertical starting line and let the corner pieces on both sides of the wall end up being cut.
Lastly, to be clear, in my descriptions I am talking strictly about pattern layout. I know better then to start laying with the bottom course but I can’t place my ledger board until I decide how I want the layout…
Thanks for your help!!
Hi Shawn,
To be honest, if given the choice, I would begin with a full tile at the TOP of the shower (or do your layout so it falls like that) and let the bench fall where it may. My second choice would probably be full at the bottom and cut at the top. While it always looks better when the grout lines on a bench line up, they rarely do simply because the height of a bench never fits the size of tiles.
It looks fine when they don’t.
Being a female, you are right about the shower seat being used to shave her legs. There has been one consistent error in building the shower seat. There isn’t ever a place to hang on while standing on one leg. It is always a balancing act…. to fall or cut myself??!!! It gets slippery with all of the creams we use to stay soft for men. Am I right ladies?
Thanks Garnet, didn’t know that. I’ll need to find some way to incorporate subway straps into the shower ceiling…
Roger,
I have built a shower bench out of 2×4’s and 3/4″ ply. I was planning on running a Oatey shower pan liner up and over the bench. Above, you said to screw cbu to the front of the bench which would then go through the liner. Would this then jeopardize the waterproofing? Or, as long as the screws aren’t put in below the level of the curb, this just acts like the screws on the wall? Thanks for the help.
Mark
Hi Mark,
You can put screws in there provided they are three inches above the top of the curb. You need to use mud on the top, though, you can not penetrate your liner on a horizontal surface.
Thanks Roger. Having cbu on the front of the bench seems a bit easier than using deck mud. But, would you recommend using the mud with a wire lathe?
Mark
You don’t use deck mud, you use wet mud. It’s deck mud with lime in it to make it sticky. And yes, wet mud with wire lath is the way to go with it.
Can a corner bench (foot rest) be made from a 12″ tile cut diagonally, resting on top of the tiles below, or does it need framing to carry the load down to the floor? Space is tight, so it would be nice if the foot rest didn’t project all the way to the floor…
Hi Steve,
Yes, it can. I do it often.
Hi Roger,
We recently built a new shower, including a bench made out of 2×4’s. The bench top is marble and a glass shower enclosure will sit on the bench. The bench is open underneath (not an enclosed box style), but sits on a wood frame. The face of the wood frame was tiled. Waterproofing board was used in the shower and around the outside of the bench. However, when I looked under the bench, I noticed exposed wood on the underside of the bench (the 2×4’s) and no waterproofing or tile. I’m concerned the wood will get wet, and possibly develop mold. In your opinion should this area be waterproofed as well? Thanks! Carla
Hi Carla,
Absolutely it needs to be waterproofed and sealed up. I’m also a bit concerned with the term ‘waterproofing board’, I hope you mean a topically faced board and not just cement board, right? Cement board is not waterproof.
Thanks very much Roger. The product they used under the tile us wonderboard – is that ok?
It’s fine as long as it’s waterproofed. Wonderboard by itself is not waterproof, it is water-stable. That just means it doesn’t fall apart, swell or disintegrate when it gets wet. Water will, however, still soak through it. It’s just like your driveway when it rains, it gets dark because it has soaked in water. It still needs waterproofing behind it or over the face of it.
Thanks for the helpful info!
Hi Roger,
Talk about perfect timing! I’m undertaking a shower reno w/bench for my mother-in-law and after reading above, I have one question. The plan is to cover the walls with Permabase CBU and cover it with Redgard after applying thinset to the joints, but you mention above that the top must be covered in deck mud after having the CBU stick up approx. 1″.
My question is this – For this type of waterproofing, (Redgard over CBU), would the CBU fasteners still pop through the waterproofing as you describe above, or is that only for certain types of installations? My plan was install the tile directly on the sloped top of the bench, but after reading above, I’m wondering now if additional steps have to be taken to prepare the top?
Regards,
Jeff in SK
Hi Jeff,
That’s only with traditional membranes behind the backer. If you are using redgard (thanks for spelling it correctly – nobody does!
) then you can just cover the entire bench with permabase and paint it with redgard.
Hi Roger,
I have enjoyed your site for a long time. I am now ready to build the master shower with bench.
The shower is wood framed (doug fir KilnDried) lumber rectangular 38″ x 68″ with an angled 28″ wide hinged glass entry door. the bench will at the rear wall and go wall to wall. It is planned as 38″ wide x 21″ high x 16″ deep.
I had long ago purchased the 1/2″ hardibacker board to do the shower walls and bench -did not know about kerdi systems when i purchased..
The shower floor is 3/4″ osb and we are getting quotes to have a poured concrete pan installed
I want to be sure I understand the bench method using hardibacker as substrate and have a few questions also about how the poured pan integrates with the hardibacker bench.
We bought your shower construction book -ebook- several months ago
1. It appears from your sire that we frame the bench out of wood. Ours will go wall to wall in the rear of the shower on the non shower head /entry door wall.
2. How at this point does the shower pan lines/mud pan installtion integrate with the wood framed bench? If they use a rubber pan liner and it runs partially up the front of the bench and then the mud pan runs a few or several inches up the bench how does the hardibacker interface with the mud pan at the top of the mud pan-it seems this would be an area that would be difficult to seal. This interface of mud pan and hardibacker applied to shower walls and bench after the pan is placed is confusing me. Do you have photos or can you explain?
3. Once we do put hardibacker on the bench after it is framed-should we put silicone caulk along the bench to wall interface to help prevent leaks?
4. We would then out redguard on all the shower walls as our waterproofing before tiling the shower walls and bench. Should we also then put more silicone caulk (rather than grout) on the bench top where it interfaces with the side and rear walls as an additional help against leaks- or not?
Right now our biggest black hole of knowledge is how the bare framed bench and other framed shower walls interfaces with a shower rubber liner and mid pan .
Your help is greatly appreciated. Thanks for bringing your knowledge to help a lot of us out here.
Sincerely,
Jean
Hi Jean,
The floor liner runs up the walls a minimum of three inches above the finished height of your curb. the hardi is then fastened to the wall studs down to about an inch above the floor – no fasteners are placed below the top of the liner. You do not need to seal the hardi/liner interface. Gravity pulls the water down, that’s it. As long as the redgard is painted below the height of the top of the liner behind the backer it will be just fine.
No need for silicone caulk there, before or after the redgard, but you can if you want to, it won’t hurt anything.
Roger,
I am building a shower in a rectangular area that is about 33″ by 54″. I was thinking that building some convex curved triangular shaped benches in the back corners would give the box space a nicer feel sort of like an oval bathtub. If I build these out of plywood, can I just coat the plywood with HydroBan? I already have hardibacker on the walls and a concrete floor so I just need a substrate for the benches that is also suitable for HydroBan. I also thought about building the shaped benches out of bricks and deck mud although I’m not sure how easy it will be to make the tapers to the wall.
Thank you,
Vicke
Hi Vicke,
If you use wet mud you can shape it any way you want it at all. Wet mud is 1 part cement, 1/2 – 1 part powdered masonry lime (hydrated lime) and 4-5 parts sand.
Thank you, Roger. I’ve seen you talk about adding lime before. Does this make the mud waterproof or do you still need the HydroBan to seal it? Also, if you add to it after one section is dry, do you use a thinset slurry like when you put deck mud on the concrete floor? (I read that in your book!)
Lime makes the mud sticky. You still need to waterproof it. You need to build a frame out of wood and backer, then form the curves and shapes you want out of the wet mud. You do not need thinset slurry if adding to already cured mud, wet mud will stick.
I am building a drop-in tub enclosure with a separate shower attached end-to-end. There will be a glass shower wall between them. The tub deck is 2×4-framed (thank you for the warning against using treated lumber – I was tempted) with a 3/4″ exterior plywood deck, which is a substrate for 3 cm granite (not in place yet). The (non-faucet) end of the tub deck is a 14″ deep shower bench (under the glass shower wall), and the bench is sloped just over 1/4″ toward the shower drain. The bench is full tub deck width, and will be covered with the 3 cm granite. (There is a seam in the granite allowing the bench part to slope.)
I tried to follow your guidelines the best I could and plan to use Red Gard on top of the cement board for waterproofing.
My question: Do I use Red Gard on the plywood under the granite? If the granite is sealed, that will create a moisture trap. To not waterproof under the granite seems risky. Do you have a recommendation? Thank you, Floor Elf.
Hi John,
You do want to use redgard under the granite. It would also be better to have backer beneath it as well, with redgard over it, rather than just the wood. Sealed granite will not create a moisture trap. It isn’t sealed against water vapor getting out (which is what gets trapped), it’s sealed against stains getting in.