Roman tub replacement. [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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06-18-2019, 10:06 AM
Done the ensuite (Thanks for all the help CX, Davy, Wolfgang, Jim, Dan, and Kevin, to name a few!). Time to tackle the main upstairs bathroom, with a disgusting old tub I've been using as a construction washup area.

I've been looking at inserts to replace the tub, but it seems there are tubs meant for showers, where the tile goes over the tub on two or three of the sides, and then tubs with a lip all the way around that don't look like they are meant to be in a shower, just used as a tub. Since my tub doesn't have one full open wall, I don't know that a shower tub will fit properly? I hope I'm making some kind of sense here.. hopefully the photo will help explain. With one end of the tub extending passed the wall, being covered on all sides, I don't know if I could make a proper tile to tub transition?

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John Bridge
06-22-2019, 06:55 PM
Hi Jesse,

Tear it out. Redo it as a roman tub or put a floor in and make a conventional shower out of it. Don't mess with inserts.

06-23-2019, 02:12 PM
Thanks for the response John. I'll look into doing another Roman tub but I'm not sure I want to go that route from what I've seen people here saying about them (seems quite difficult).

Would like to still have a tub though, rather than converting to a shower.

Just found this product, anybody have experience with this or something similar? Seems like it would solve my problem, I could get a regular 72" drop in tub and then just install the tile flange where I need it.

06-23-2019, 08:40 PM
I would tear it all out and try to find a tub that has a flange already made on the tub.

06-24-2019, 01:48 PM
I don't think any tub will have a built in flange to go around all three sides on the one end of the tub sunken into the wall though.

06-24-2019, 02:19 PM
How does that Home Depot flange seal to the tub surface I don't understand this? What's in that little pop out feature next to that tub that's causing this problem?

06-24-2019, 06:50 PM
What Jessie said, something will have to be done about the third wall. May even have to fur out the wall to fit the tub.

I've never installed one, Teddy but I believe epoxy is used to bond it.

06-25-2019, 06:30 AM
I'd probably try to use a drop in, then fur all the walls out above the rim so that the tile is held back from the inner edge of the rim by a minimal amount, no more than 1/4". Since the rim will probably be at least an inch wide, probably more, it should give you enough space to bond Kerdi to it to create a seal.

Will require some very accurate measuring and framing, and probably some compromises in adjoining wall surfaces.

02-28-2020, 02:29 PM
I couldn't decide what to do about this so I put it off in favour of other projects, but the time has come!

I leaning to just redoing as a Roman tub, more labour but less cost, and better looking. Insert would also require drain relocation and would be finicky getting something to seal around the edge, problems more likely.

When I did the shower stall I went with a conventional pan and cement board with redguard on the walls. I've seen some videos of people doing Roman tubs with liquid membrane but it makes me leery, how many folks here trust liquid membrane in a roman tub? I was thinking maybe I'd try the kerdi or equivalent membrane product for this project, at least for the tub portion. How well would it work though, for compound angled inner corners, like the bottom of the tub has?

Just fixed the paddle bit on the hammer, about to go have some "fun".

02-29-2020, 09:17 AM
What are we looking at in post 1, are the tiles still installed in that picture or are we looking at concrete that once had tiles installed? What about the drain, what's it look like and how would a membrane connect to it?

I wouldn't want to fold a sheet membrane over that surface.

02-29-2020, 11:21 AM
Tiles still installed in post #1, got a bunch off and the floor up yesterday.

Went through this thread yesterday as well:

Looks like the biggest problem with the Roman tub plan is the drain. I'm not going to be paying $600 for a custom unit, and looks like the kerdi isn't good for submerged applications anyway. Maybe I will just do a shower stall?

If it's as simple as getting a drain that bonds to liquid membrane like you would use for a shower stall, but one that has a stopper, and you basically make the curb higher and have a tub, then I'm in. Doesn't appear to be that easy though.

I'll post some more pics when I get all the tile off. Kinda surprised, when I demoed the old 70's shower stall the waterproofing method was a layer of fiberglass over plywood, was built very solid. The bath though, has no waterproofing, just tiles on drywall. Only found one little spot of water damage so far though.

03-04-2020, 01:07 PM
Doing some more reading about the drain, seems to be the sticking point. Divot method with a conventional stopper drain would be an option, but there must be a way to make a liquid membrane drain work with a stopper?

A lot of hate out there for Roman tubs. Is all the talk about how difficult it is based on the old liner days? Seems like raising the curb and reinforcing, switch the drain for a stopper unit, and liquid membrane like normal wouldn't be much harder than a shower stall. What am I missing?

Still flip-flopping between shower stall and tub, Help me decide what to do with this thing!

P.S. What drain should I use if I go the shower route? Having trouble finding a liquid membrane drain at homedepot. This video shows a guy using what looks to be a drain for clamping on a fiberglass shower, then I guess he just covers the lip with redgard? Is this acceptable? I went with the 3 piece and liner on my first build, but I'd like to try a newer method on this one.

Edit# 2: Looks like the only proper bonded flange options are the same kind of drain you use for a sheet membrane? So Laticrete/Kerdi/Noble kind of drain? Looks like this is my cheapest option if that's the case:

Does anybody use the really cheap drain like the guy in the video? Seems like it might not have enough boding area. Spending another $60 on the drain to skip the liner and extra mud bed is already worth it anyway.

03-04-2020, 04:33 PM
The Kerdi is approved for submerged applications, just not with the regular thinset application. In Europe, Schluter markets a product called "Kerdi-Coll." That in conjunction with perhaps more overlap should give you a waterproof application. I am not sure if this product is available here in the US. You might want to call Schluter and ask them about their recommendation.

03-04-2020, 07:43 PM
Jesse, first question I'd ask myself when considering trying to re-use that tub (very briefly consiering) would be, "Will I actually use the tub?" The I there would, of course, include any of the household members.

I've had many requests over the years to remove a tub and replace it with a walk-in shower or just make it go away, but never once had a request to install a tub where none had been before.

Looking at your current tub, I can't imagine being able to fold a sheet-type direct bonded waterproofing membrane to fit the shape and make waterproof seams. Just not gonna happen. I like to think I've gotten pretty capable with those products and I wouldn't even try it.

That would leave you with only liquid-applied membranes and I don't know of one I would trust in that application. Might work with one that used a reinforcing fabric over 100 percent of the surface, but I'd be skeptical even then.

If you really, really want a tub in that same space, I'd recommend removing what you have, making what would effectively be a walk-in shower and make a high curb across the opening. Again, use a sheet-type direct bonded waterproofing membrane and a bonding flange drain. Any shower curb higher than 9 inches is considered a tub, by the way.

While the Kerdi membrane may not be manufacturer approved for submerged applications, I do know that back in the day (2005ish?), when Dave Gobis ( was running the CTEF, any number of cardboard boxes were converted to test vessels/drink coolers by applying Kerdi to the interior of the box. At least one of the boxes was filled for years, if I'm recalling correctly, but at least many months, and Dave would occasionally add a little soap or other cleaning product to make the test more realistic. And the same box, or one of the similar ones, would be filled with ice and drinks to be used by the attendees. And I believe this was before Schluter started offering the pre-made corner pieces. All fold-your-own back then.

It can be done. Good idea to try it in your application? Up to you.

I've heard of the Kerdi-Coll, but have never seen or touched any, despite having been to a small handful of Schluter seminars. Might be worth trying to get some if you elect to continue with the tub project.

Were I to do what I described above I'd want to use the USG Shower System membrane. Thinner, easier to fold, makes better overlapped seams.

My opinion; worth price charged.

03-04-2020, 08:34 PM
If you're gonna go back with a roman tub, I'd find the drain first and use the membrane that will work with it.

I wouldn't have a problem using a paint on membrane such as Hydroban. The fabric is a must.

I don't like the drain in the YouTube video.

03-04-2020, 10:36 PM
I'm leaning more towards taking out the tub and converting to a shower stall. Don't seem to be any liquid membrane stopper drains anyway, other than custom built units.

So I think it's settled now, going with the shower stall, and instead of a tradition preslope+wet mortar bed I'm gonna try the liquid membrane pan this time.

Does the drain I posted from home depot look ok to use with a liquid membrane? Seems to be the most economical of the bonded flange drains.

I was curious what this tub had for waterproofing, as I mentioned before, the shower stall in the ensuite was built like a boat, thick fiberglass over plywood. The walls in the tub/shower were just tile over drywall, and the tub has vapour barrier poly for waterproofing! What a joke. Why waterproof the shower so much and the tub so little? Doesn't make sense. No major damage yet though, wood under the poly still solid, so far.

03-05-2020, 06:24 PM
Jesse, what's in the last picture? Is that the curb and what is it made of?

Is it too tall to use as your shower curb and is it in the right location?

03-05-2020, 10:12 PM
I'm currently demolishing the old tub. Chipped off all the tile, now breaking apart the mud. The photo up there is the wall of the old roman tub. Was just mud over plywood with that thinner-than-a-grocery-bag old vapour barrier, with staples and nails all over it, and it's over 40 years old, can't believe the plywood underneath is fine, so far.

Here's a a more bird's eye view of the whole operation, showing the outside of the bathtub wall.

It's in the right location, but it's 2x6 and much too tall to use for just a shower. Too bad there wasn't a drain for a roman tub, I probably could have just chipped out and replaced the drain, then redgarded the mud and kept the tub. Oh well, no proper drains readily available and had no idea how bad it was underneath without digging.

Can anybody help me with that AlinO brand drain?:

Any bonded flange drain works with either sheet or liquid membrane, from what I understand, so this thing should be fine?

03-05-2020, 10:20 PM
Jesse, until this thread I'd never heard of that AlinO drain. Looks like a Kerdi knock-off, but I can't find any information about what it really is, what it is supposed to bond to nor what it's supposed to bond with.

If you wanna guess that it is compatible with whatever waterproofing membrane you wanna use, that's entirely up to you. If you find any technical data or installation instructions from the manufacturer, please do give us a link.

[Edit] OK, I found some rudimentary instructions ( saying a waterproof membrane is installed using "Modified mortar." Nothing more specific than that. I found nothing at all about meeting any tile industry or plumbing industry standards.

My opinion; worth price charged.

03-06-2020, 10:54 AM
Yes, looks like a "knock off" or, another option at this point. Don't know how to tell if it's certified. They have the full shower kits and such with sheet membrane. Looks like a Canadian company, or resaler and rebrand of something else. I guess I'll email them about using redgard.

Is the kerdi drain compatible with liquid membrane? Looks like people use it with liquid membrane, but I can't find any documentation about it. Is laticrete the only liquid membrane drain?

I really just need someone to tell me what drain to get for liquid membrane bonding without divot and old 3 piece. I see lots of examples but I can't find anything about the mythical liquid membrane drain, other than laticrete, which is very expensive and difficult for me to get through international order.

03-06-2020, 11:23 AM
you can do whatever you want, but the kerdi drain is only approved for use with kerdi.

take a look at this supplier....

03-06-2020, 01:07 PM
Not trying to do what I want, I'm trying to find a bonded flange drain meant for liquid membranes. Is the laticrete one really the only option?

03-06-2020, 07:06 PM
Jesse, I've never used a Laticrete drain so maybe someone else will chime in on that.

When you were talking about keeping the roman tub, the paint on membrane was my first choice due to the odd shape. Folding a surface membrane or pan liner would be tough in a roman tub. But, now that you're going to turn it into a shower, I'd use a traditional pan liner with a preslope. Others here will suggest a surface applied membrane, which is fine too.

03-06-2020, 10:06 PM
Are you trying to save a few dollars by looking into these knock-off drains? I understand the sentiment but think that saving on the drain would be ill advised. Whatever you decide to use for water proofing, get a suitable drain from a reputable manufacturer.

03-07-2020, 01:26 AM
I looked into the AlinO drain cause it's locally available, which means it's been CSA approved, which means I would trust it regardless of whether it's a "knock-off". What I'm trying to do is find any bonded flange drain that'll work to use with a redgard pan liner. The laticrete hydroban drain seems like the only one specifically for a liquid membrane, but they probably only certify for hydroban, even though it looks like it's perfectly fine to use any bonded flange drain with either liquid or sheet membrane, from what I'm seeing. Makes sense I guess, they're all drains you bond to. Too bad Custom Building Products didn't make a drain to reduce this confusion.

Davy, I did the traditional pan liner for the shower stall in the master for my first go at a bathroom reno:

I'm happy with how it turned out, but I'm looking to try a more modern method this time.

03-07-2020, 01:38 AM
Jesse are you located in Canada?

03-07-2020, 03:34 AM
Hi Kevin, yes, I'm in Canada.

Not bad for a tub built in 1976 with thin poly vapour barrier beneath fat mud float, nails throughout. A bit of discolouration in the plywood but no serious rot or softness anywhere. Bit of mold and drywall damage on one of the ledge corners but that's it. Pretty amazing, I thought there'd be some ugliness for sure once I found out it wasn't fiberglassed like the ensuite.

03-07-2020, 08:09 AM
Have you tried Laticrete's Distributor Locator ( Even if one is a distance from you, you may get shipping directly from them.

03-07-2020, 06:16 PM
FWIW, I think Ardex makes a product very similar to Kerdi-Coll, and, they will warrant its use with Kerdi.

I do think that you could use a drop-in tub and seal the tub-wall after installing their (often optional) flange kit to Kerdi, or similar sheet materials or Kerdiboard, etc. I really would have liked a 7' tub, but could only fit a 6' one when I did my remodel. A 60" one, is just too small for most adults...fine for children, though. They tend to be available in 6" increments, starting at 5'.

03-08-2020, 12:21 AM
Thanks Kman, I'll try calling a couple places on there and see what's available. Currently I have to spend about $160 to get a Hydroban drain, and doesn't really seem much different from the Kerdi.

Makes me wonder if I should bother with the Hydroban drain, but I'll call around and see if I can get a decent price. Seems very similar to the kerdi, and even if I get the hydroban drain I'll still be out of spec using redgard instead of hydroban liquid.

I emailed AlinO, they told me their drain is fine with redgard, but then tried to persuade me that their membrane is better, of course. AlinO is cheaper and appears to be a Chinese knockoff, but they offer a warranty (if you use all their stuff, like everyone else) and if they're sold at the local home depot they're fully CSA certified, so it can't be crap. Might go that option.

looks like no matter what, if I'm using regard there's no approved bonding flange install. I'd have to go divot and 3 piece, which I don't want to do, and I don't want to waste senseless money ordering equivalent products just so everything matches. I doubt anyone would fulfill a warranty claim on my DIY job anyway, and like everyone here says, if it fails, it was probably 99.99% my fault, not the product.

So unprofessional advice, would you buy the Kerdi for $100, doesn't offically work but surely higher quality, AlinO for $80, save a few shekels and they say it works, or spend a possible $160 on the hydroban drain, the only one specifically for liquid membrane, even though they only warranty their own liquid. I haven't looked into it but I might need need to get their wall board and everything for the warranty to work. So I'm not necessarily looking for the full certified warranty, I just want a system that will work.

Jim, I've kinda shied away from the dropin option because I couldn't find any 7 foot tubs, especially anything with a flange, and a partway flange down the fourth side as I would need. If you know of anything that'd work please let me know! I'm almost set on the shower now though, but could reverse course if there was a nice tub option.

03-08-2020, 01:59 AM
Does anyone here have experience doing this?

I see lots of full epoxy showers on the internet. I've been using epoxy coating on 3D printed submerged boat parts for many years, UV exposure and all, no problems.

I'm thinking about making a curb and shelf area in a walk in shower from wood, stained and then coated in marine epoxy to completely seal it.

Anything I should look out for? Any reason why I shouldn't do this? I was thinking for adhering the coated wood, to either rough up the bottom with some 40 grit and use some versabond, or do the same and just use some of the epoxy itself. I'll try some samples of each and do some destructive testing. Looks like granite curbs are often adhered with epoxy.

Wanna run this by people who know a whole lot more about this kinda stuff than me, to see if I'm overlooking something.

03-08-2020, 06:41 AM
I doubt Versabond will stick to the marine epoxy. What's the purpose of all this? Sounds like a lot of extra work and expensive materials.

03-08-2020, 06:52 AM
My first thought was “there will be so many glass guys lining up to drill this curb they will need to have a raffle!” :D

03-08-2020, 09:42 AM
So unprofessional advice, would you buy the Kerdi for $100, doesn't offically work but surely higher quality, AlinO for $80, save a few shekels and they say it works, or spend a possible $160 on the hydroban drain, the only one specifically for liquid membrane, even though they only warranty their own liquid.Professional or unprofessional, Jesse, I would not use a liquid-applied direct bonded waterproofing membrane for a shower receptor at all. For a sheet-type membrane I'd choose the USG Durock Shower System membrane and drain. Reasonably priced, available on Amazon.

As for your AlinO products that some of us have never heard of, that's entirely up to you. It may be perfectly usable, but we just don't know that. As for: and if they're sold at the local home depot they're fully CSA certified, so it can't be crap. if you'd add a geographic location to your User Profile that might be a bit more meaningful, but I'm still not sure it would be accurate.

Bottom line is that it all depends upon your personal risk tolerance and your willingness to pay for known useful products. While I understand your wanting to be frugal, I also understand the situations where you've got to weigh a little added expense against the knowledge that the products, and combination of products, you're using have been well tested and are likely to last over the long term.

In my professional life that means I never get called back to a project because of a failure (shower re-dos are very, very expensive) and in my non-professional life that means I never, ever hafta go back in there for any reason. In either case, even when I can't really afford the extra hundred bucks, I'll spend it if I think it puts me in that sweet spot.

Those are personal choices and nobody outside can really help you make them.

My opinion; worth price charged.

03-08-2020, 09:44 AM
Two questions:

First, exactly what do you mean by a "full epoxy shower?"

Second, is this part of your roman tub project?

03-08-2020, 09:54 AM
In a prior life, I knew a fiberglass guy who 'glassed and entire shower in place in a prison. He's gone and I can't tell you how it fared. I'm assuming when you say epoxy, you're going to reinforce with fiberglass mat or roving or chop?

It does beg the question why, though. With all the various proven-to-work methods to choose from, what would be the benefit?

If the smoothness of 'glass is desired, why not install a prefab?

Is it a secondary waterproofing you're after?

03-08-2020, 11:13 AM
by full epoxy shower I mean something like this:

Just type "epoxy shower" into google and check out the photos/videos.

I'm not doing any fiberglassing, I just like the idea of using some wood that I've stained for the curb and a ledge/shelf in the shower, and fully coat in clear epoxy to seal it. This wouldn't be overly expensive at all, rather I expect it would be quite a bit cheaper than going the granite route.

And yes, CX, this would be for my Roman tub project that has now turned into a walkin shower, but I thought this question was broad enough to stand on it's own.

03-08-2020, 11:31 AM
Let's keep all the project questions on this thread so folks can see what you're working on and what's been previously asked and answered. A moderator can give it a different tile if you'd like.

If I were wanting some exposed wood in a shower I'd want it to be Teak or Ipe or similar. If you want to try your epoxy coated wood, I'd wanna make the pieces easily replaceable.

My opinion; worth price charged.

03-08-2020, 04:23 PM
Any wood with an epoxy coating would stand up better than uncoated teak. Epoxy is completely waterproof like fiberglass resin. I think I'll give it a try.

Back to the waterproofing system, what a minefield. This morning I had started thinking, why mess around, just get a kerdi drain and membrane and do the whole thing the kerdi way, I could even just leave up the old drywall to avoid the annoying disposal ordeal and board over it with some 1/4".

Then of course today I had to find Isaac Ostrom's Youtube channel with all the kerdi fails. Yikes. Maybe I should just go back to the 3 piece and liner with double mortar bed.. or do something unapproved like paint the kerdi seems and around the drain with redgard. I like the idea of using the ardex 8+9 over the kerdi membrane for the pan, being cement based, but I can't easily get that stuff.

03-08-2020, 04:47 PM
After looking at the epoxy showers I see now what your goal is, somewhat. Not a bad idea and if you follow thru it would be nice to see some pics of the results. :) I had no clue that stuff was out there.

03-08-2020, 05:06 PM
Jesse, while I find Isaac's videos interesting, I've personally witnessed too many cardboard boxes Kerdied on the inside and filled with water for months and, in one case, years without leaking to think the system won't work if properly executed. Just too many Kerdi showers out there for decades now for us not to have heard of some failures if there was a serious problem with the system.

My only deviation from that is that I've come to prefer the USG Durock Shower System membrane rather than the Kerdi membrane. Same approach, better material.

My opinion; worth price charged.

03-08-2020, 05:49 PM
I think it's important to note that what Isaac subjected the shower to is something we never see in a conventional shower. And if you overlap from the bottom up, like I do, then the only way water can get into those seams is for it to start running uphill.

03-08-2020, 06:02 PM
Which it will, in fact, happily do in that application, Kevin. :)

03-08-2020, 07:45 PM
If you look closely to that mentioned video, you'll see a lot of thinset, puckered seams and some other deficiencies. You need to use the right-sized trowel, mix the thinset properly, wipe the surfaces down for dust and to add a bit of moisture prior to spreading the thinset, and get the right-sized overlaps without excess thinset thickness. The stuff works. It's not all that hard, just attention to detail and an understanding of the system.

Do everything right, and moisture will tend to penetrate the seam maybe 1/4", but with at least a full 2" overlap, more than enough.

03-08-2020, 09:48 PM
Which it will, in fact, happily do in that application

You mean run uphill in a shower? I wasn't referring to flood testing, by the way.

03-08-2020, 10:00 PM
I agree that it's not common, but I wouldn't say a shower would never be subjected to that. Sometimes things drip and aren't remedied. The sprinkler test he did shows it doesn't have to be submerged for water to penetrate, just a constant source will do it.

I went down the youtube rabbit hole today, discovered the beef.

While I'm sure the kerdi system is fine, I mean, much better than thin poly stapled to wood in a tub that lasted over 40 years, it's still definitely preferable to have no water migrating anywhere at all. Liquid membrane insurance over sheet membrane doesn't seem like a bad idea.

03-09-2020, 05:49 AM
If you look closely to that mentioned video, you'll see a lot of thinset, puckered seams and some other deficiencies...
Exactly my take when I watched that video. Whoa, that looks like a lot of thinset mortar, thickly applied.

03-09-2020, 07:04 AM
Liquid membrane insurance over sheet membrane doesn't seem like a bad idea. If you like the liquid membrane, Jesse, why bother with the sheet membrane at all?

03-09-2020, 11:29 AM
I don't believe the accusations of installer error on Isaac's part. He has multiple tests, even patch tests with differing amounts of thinset left under the band. Simple fact is that thinset isn't waterproof and it wicks water, no matter who installs it.

I like both membranes. Liquid is prone to pinholes and cracking while sheet membranes applied with thinset have wicking problems at the seams. Sheet membrane with liquid protection on the seams doesn't seem like a bad idea at all.

I can understand the stick to one system sentiment, but manufacturers never back up a warranty anyway, so when you see multiple tests showing water coming through with one method and not when you take a few minutes throw in a little liquid membrane, makes sense to cover your ass.

03-09-2020, 11:33 AM
Well, you've clearly made your decision, Jesse, so I say "Go for it."

Someday you may find out if it all worked out well for you.

03-09-2020, 01:42 PM
Haven't yet completely made my decision.

Since I completed the ensuite bathroom denshield has become available in my area, just noticed it. I think I'll go that route after some calculating. Still undecided about a traditional 3 piece drain and liner or the kerdi+liquid. Traditional would cost less but more labour of course.

Quick cost comparison:

Denshield = $1.38/sq.ft -already waterproof
kerdi = $2.18/sq.ft + $0.45/sq.ft drywall = $2.63/sq.ft
Redgard = $1.80/sq.ft + $1.30/sq.ft cement board = $3.1/sq.ft

Walls with Denshield is a no-brainer here for me. I'll tape/thinset the seams and coat only the seams with redgard, or ardex 8+9 if I can get my hands on some.

For the liner I can go with traditional:

Drain = $20
liner = $40
extra deck mud = $10

Or Kerdi:

Drain = $100
Kerdi membrane = $100
Kerdi corners = $60

So an extra couple hundred to go the kerdi membrane and drain route. Pretty sure I could do another mudbed in a couple hours and basically pay myself $100/hour, but I'd like to try something new now that I've done the traditional build.

If I go traditional I guess you can't stick the denshield down into the mudbed to hold the bottom in place like you can with cement board. When I did my other shower, I dipped the bottom of the boards in redgard, front, back, bottom endge and sides. Just sealed up the bottom couple inches so it couldn't absorb anything out of the mud bed, even though it's cement board. I guess I could do the same thing with the denshield. I don't like the idea of leaving a gap to the bed with nothing holding the bottom portion of the walls until past the liner.

03-09-2020, 02:11 PM
Jesse I've done a couple with sheet membrane and hit the seams with Regard just for extra insurance. I wasn't really worried about the floor so much, but rather the places where we tend to see failures.

So I hit the seams on the corner benches, the curb, and the bottom of the niches. I guess if I was flood testing I might hit all seams below the top of the curb just to avoid the inevitable questions from a customer about moisture migration.

03-09-2020, 03:49 PM
I did nothing of the sort. Just Durock's membrane on the shower floor - with a seam the length of the 83" floor, Kerdi pre-formed inside corners, Durock water proof foam wall boards, and Durock 5" membrane band to tile the floor to wall and wall seams together. Durock drain. Same treatment for the corner benches, or of which gets inundated with water.

48 hr flood test, and continuous use for the last 5 months, often with both shower heads running. Certainly not a long term test but zero evidence of any leak.


03-10-2020, 11:10 AM
Thanks for mentioning that Kevin, makes me feel better about doing it myself.

No Durock available for me, except the cement boards. Unless I wanna gamble on some trugard or AlinO membrane I'm stuck with Kerdi.

Time to get the old drywall down and do some plumbing. Thinking I'll just leave the ceiling drywall up and make a groove for the pex, and then just board over it. Need to leave the space to have the pex inside the insulation anyway.

03-10-2020, 02:44 PM
Durock Shower System membrane is available to you from Amazon and from Contractors Direct, Jesse.

03-10-2020, 03:34 PM
Only the Durock membrane band is available from, not the actual membrane. Contractors direct would mean ordering from the USA, which means expensive shipping and customs/brokerage fees.

At least we have denshield now. Saves time and money compared to anything else.

03-10-2020, 06:36 PM
I find the membrane available on Amazon here. (

The part about shipping is one of the reasons I invited you earlier to put a geographic location in your User Profile, Jesse. Helps with a number of different kinds of questions.At least we have denshield now. Saves time and money compared to anything else. You'll wanna be careful with that.

My opinion; worth price charged.

03-11-2020, 02:00 AM
Added location. CX, It's available for you on, not available for me though, won't ship to my location. Usually if it's available in Canada it's available from

CX, can you elaborate why I should be careful with denshield? You're vague warning is begging a question.

I need to relocate the drain. Currently it's a 1.5" running into a 2" that also gathers the 2" shower drain from the ensuite. Seems there's also another 2" drain capped off you can see in the photo where the 1.5" goes into the T. I have no idea what that's all about.

For a shower with 1 head minimum code is 1.5" from what I understand, but the shower stall in the ensuite had 2" while this roman tube + shower has 1.5". Currently the 1.5" has a slight grade as it has to pass under the 2x12 before coming up. When I move the drain into the center it won't have to pass under the 2x12 any more and I can give it a 1' drop over 3' before it hits the 2" downspout or whatever it's called.

So what would you folks do? Should I not worry about the 1.5" cause the grade to the 2" can be so steep, and only 3' span, or would you cut the 2" downspout thing and put in a new T to do a 2" all the way? That looks like it might be tough because of the other 2" T being so close, not enough pipe left to connect another one.

If I leave in the T with the 1.5" side outlet, what's the best place for the bushing to bring it up to 2" to fit the drain? Right near the T? Or right before the drain?

I will add that the shower in the roman tub never had trouble draining before with it's slightly graded 1.5", but still worth asking about.

Photo explanation: The paper towel is in the current drain location. Rectangular hole is where the downpipe T is that the 1.5 inch travels to from current drain location. Photo under the subfloor is facing towards the T, showing how when I move the drain (to the right in the photo) I can increase the grade to the T after clearing the joist.

I got all the drywall off today and planned my bench and plumbing scheme. Cut off the old copper and removed the whole faucet assembly that was welded together rather than bothering with the puller. Soldered on some pex adapters and added some shut off valves so I could turn my house water back on. (probably should have shut off valves anyway, I can access them through the opposite wall if needed) All of the walls around the tub have been insulated, is this normal? Should I just leave it there, any reason to remove it?

03-11-2020, 08:37 AM
Jesse, that DensShield is a gypsum-based product. They call it water-resistant gypsum, but it's still gypsum. The fiberglass coatings are listed as a moisture barrier rather than a waterproof coating. It cannot be burried in the top mud bed of a traditional shower receptor to provide stability where no mechanical fasteners can be used and they depend upon a bead of flexible sealant at the bottom of the wallboard to protect the gypsum interior. The manufacturer no longer requires any waterproofing over the mechanical fasteners nor over the seams in the wallboard. The seams are taped with fiberglass mesh and thinset mortar.

It may be a useful product if properly applied, but I'm just not particularly comfortable with it in a shower application as designed, but see my warranty information below.

It is my understanding that your 1 1/2" shower drain is perfectly acceptable, but the only place you can make a transition to a 2" shower drain is immediately at the drain fixture itself. A 2" to 1 1/2" bushing there should meet any code compliance inspector's requirements, but you cannot reduce the drain size anywhere downstream of that.

That should all apply anywhere south of the 49th parallel, but I can't testify at all about Canadian code.

My opinion; worth price charged.

03-11-2020, 11:38 AM
Just checked the price of the USG membrane on contractors direct site; $60 for 25 feet versus Kerdi at $158 for 23 feet at Homers. Wow, big difference.

Wondering I should stock up on a couple rolls of USG for my two bathrooms. Be nice to know when and how the USG line will be reincarnated!?! :twitch:

03-11-2020, 01:03 PM
Me, too, PC. Haven't heard a peep since the last time we had that discussion on here and that's weeks ago now. I really hope we don't lose that membrane as it's a superior product in its genre.

Stocking up might be a very good plan, though. Don't think it has any shelf life restrictions. None known, anyway.

I don't plan to build any more showers, but one never knows. Won't bother me to use a Kerdi drain, but I do want that USG membrane.

My opinion; worth price charged.

03-11-2020, 05:20 PM
Looks like a good value indeed. Too bad contractor direct wants $130 to ship the $60 roll. Anybody wanna mail me one?

03-11-2020, 05:36 PM
'Fraid the shipping problem is on your side of the border, Jesse. We had a situation here a few years back where I sent something to one of our members who lives just across the line in BC, I'm thinking Victoria area, and the shipping charge was absolutely outrageous. Seems it would have cost maybe ten or twelve bucks to send it to Seattle, WA, and to BC it was more than fifty bucks. Lesson learned about no good deed going unpunished.

Not sure just what it was we did to piss y'all off this time, but I wish we could work it out. :D

03-11-2020, 05:55 PM
I'm in Victoria as well. Deal with the shipping problem constantly. It's the carriers that really gouge, and customs is a pain. Large companies can negotiate good rates though. When I order my electronic parts from digikey they come next day for free if I order $100 or more, or only $8 otherwise. Amazon has it well figured too, I wish it was all like that.

Guess I'll have to stick with Kerdi for now.

I won't rely on silicone to seal the desnnshiel seams. I'll either redgard the taped joints or just use some kerdi band type material over them. Won't have to worry about dipping the bottom of the board in the mud bed with the kerdi drain system.

03-11-2020, 07:47 PM
Ummm, with the Kerdi system, whyever would you be using something like DensShield as your backer board?

03-11-2020, 11:22 PM
I'm pretty much doing this:

But most likely with redgard instead, unless I can get some ardex 8+9, and without the rush. Still getting everything plumb and level, and flat.

Might do a little test of my own and silicone together a densshield box and fill it up, curious. Either way I'll be regarding seams, and I can do the whole wall if I'm not liking the results of the densshield test.

If I had a sheet membrane option other than kerdi I might just go that route on the walls too, but it costs a fortune. Only other options I have are trugard/alino/kobau/IB tools and the like from Amazon. Prova too, but it's just as much or more than Kerdi.

Probably just get the durock band for my kerdi membrane pan, since I can't get the durock membrane, but he durock band is available on amazon and better priced than kerdi band. Might aswell go full Frankenstein at this point.

In the video though, no lath is used in the mudbed, is that ok because he thinset bonded it to the slab? I'll be doing this on the subfloor, so I assume I should use tar paper and lath for my sloped mudbed, like I did in the other shower. Should I do another layer of ply over the 3/4 or just tar paper and then mudbed on that is fine? Pretty sure I just did the mudbed on the 3/4" subfloor for the last one, but can't quite remember. I know I put half inch down on top of the 3/4 sub before the ditra heat and then granite.

03-12-2020, 06:46 PM
Yes, he was working on top of a slab so he bonded the deck mud with a slurry of thinset. On a wood sub floor, you'll want tar paper (or poly) along with lath stapled down before you put down the deck mud.

3/4 plywood is good enough.

07-11-2020, 11:48 AM
It's been a while, I got side tracked, but I'm back on it now. Went with kerdi + redgard on the lower seams and denshield backer. Used some cement board too on the kerb, bench, and a couple places where I preferred 1/4" for less buildup.

Passed the flood test (hard to see water in the photo but it's there) and then rewarded myself with a tile saw upgrade. Only made a few cuts with the dewalt so far but it's very nice to use compared to my old $200 saw. Looking forward to miters with this thing, it's all so stable, nice piece of equipment.

I'm going ahead with the epoxy coated wood. I will treat it like resin backed tile as far as adhesion goes. I looked into recommendations for resin backed tile, and while manufacturers all suggest epoxy type thinset, many people on this site and elsewhere, from my searching, suggest that a good quality typical thinset works fine. I decided to test the versabond on a sacrificial piece of epoxy coated wood, epoxy roughed up with 40 grit paper. I wasn't happy with the bond, didn't work very well at all.

Doesn't seem to be a lot of info out there but this from TEC is helpful:

Would appear my options are epoxy type thinset, a primer, or another coat of epoxy with a sprinkle of sharp sand, of which I have some leftover from the mudbed. I'll do some more testing and see how it all works out. Want to make sure I have a very sturdy bond. Trying some regard currently over the resin and then will thinset bond tile over that and do another destructive test to see if the redgard works as a primer on the resin. Initial scrape test looks promising but I'll have to wait until the thinset cures so I can try to rip the tile up to see how tough it really is.

I forgot to take a picture of my mudbed, turned out decent, well formed anyway, but I still can't seem to figure out how to get it really slick on top like I see in the videos. I used a spray bottle to add a little more moisture before finishing it, which helps, but it just doesn't come out super-slick no mater how I run over it with the trowel. I'm mixing my own with bulk concrete sand and portland cement 5:1, imagine the specific premix bags come out nicer, but it's about $200 in material vs $20. I missed a little chunk of sand during my vacuuming of the bed after drying, or maybe I pulled it up while applying the thinset, could feel it under the kerdi so I cut it out and put down a patch. I imagine being able to get the mudbed super slick would prevent this. Any advice?

07-11-2020, 07:45 PM
Not sure what you mean by concrete sand. Does it have pea gravel in it? Sand is finer, say 1/8 and smaller grit. If it has pea gravel in it then it will be hard to get slick and smooth.

07-11-2020, 09:04 PM
I'm mixing my own with bulk concrete sand and portland cement 5:1, Sounds like what I get from my local redimix company, Davy, which has always been my favorite sand for dry-pack or fat mud.

07-11-2020, 09:29 PM
I like my sand with 1/8 inch grit and smaller. When it gets courser than that, it can be hard to slick down with a trowel. I'd think the courser sand would help the strength though. I guess I've never heard it called concrete sand.

07-11-2020, 09:45 PM
We call the pea gravel stuff "Navvy Jack", "concrete sand" is just like "sharp sand", smaller than 1/8", sharp little pieces. I think I have the right stuff, just lacking skill or some knowledge. I believe I might need a finishing trowel that's a bit convex, would probably help but maybe I'm just mixing a bit dry, not sure. I should mix some more up and just play around, try to get it nice and smooth on the finish.

Not a lot of progress today, but I got some miters on the bench done. Really loving this laser I got, great for layout. Was a bit hesitant with these cheap units on amazon but they have great reviews so I gave it a go, really glad I did. Can see the epoxy coated wood ledge in the background, took another one of the curb in better light. I'll report back on my redgard primer test tomorrow. If that doesn't work I'll probably just pick up some epoxy thinset.