Failure of a large mud shower pan.

[Vegas_sparky]

As to the skill set of the mudman. Its critical that he can shape/slope the shower floor correctly. Its laborious, detailed work, which must be performed failrly quickly. Experience is an extremely valuable asset, when choosing this tradesman. Someone who sets floor tile in living rooms all day may have no clue as to how a shower pan is properly constructed. The drain connection/installation is critical also.

All the above goes for installing the foam base.

The prefab plastic bases are probably the most forgiving.

 

[Paul Lepkowski]

Vegas sparky -- I wasn't thinking of a fiberglass pan. The thing I am considering is Dupont Corian like the countertops that look like marble. It is a solid resin / catalyst thing cured in an oven and weighs about 600 pounds. Thin, flimsy fiberglass is not an option.

Paul in Fishkill Plains

 

[Sponsor]

 

[Jadnashua]

If you use a bonded membrane like Kerdi, Hydroban sheet, and others and use a drain designed to work with a bonded membrane (this is called out as B422 procedure in the TCNA guidelines), then, a single layer is all you need, or want as long as it is stable and that may require some thickness, depending on what it is made out of.

If you are doing a conventional, clamping drain based shower, yes, you do need a second layer of deckmud as your setting bed. Each layer of that deckmud needs to be thick enough so it doesn't break. How thick depends on the substrate (slab or subfloor) and whether it is the preslope (bottom layer) or the setting bed (top layer). Industry standards want a minimum of 1.25" thick mudbed at the thinnest, but some manufacturers call for more when using their products (Laticrete wants a minimum of 2" with their products - will it work with less, probably, but not always).

The TCNA has a significant number of proven shower build techniques. Each one works, each one has its good and bad points and therefore benefits. Each one requires very close attention to detail. Some people skip a step or two. The surface looking good has only little relationship to what's underneath. It could look crappy, but be perfectly functional. And, as you found out, it could look fantastic on the surface, and be crap on the inside. The TCNA says 70-80% of those built aren't built right. So many 'professionals', so many failures, one wonders how they stay in business. Obviously, some actually care and do good work, but they are in the minority so it behooves you to understand how it should be done so you can spot the problematic installs, even if you aren't going to do it yourself.

I've been to a variety of manufacturer workshops and built a few things in tile...I've seen some real pros do things and critique my technique during the workshops. I've been listening to and reviewing many pros and DIY'ers over the last decade while trying to give back a little in some forums (this one, and www.johnbridge.com), and have seen the results of many failed installs. Knowledge comes in two parts: actual understanding of what's to be done, and the acquired skill to do it and make it look effortless. One doesn't need the later to understand and be able to identify a lousy job. The pros here seem to think that the manufacturers and the TCNA don't have a clue about their products, and they know better. Lots of times, you can get away with things, but if you do it all the time that way, breaking the 'rule's, some situations will come back to bite you. So, understanding what you're seeing, and why it works is crucial.

 

[Vegas_sparky]

For discussion sake, Corian is in the plastic/prefab category. These typically can't be tiled over, so your finish surface is known.

There are prefab bases that can be tiled over, but I doubt they're available in the size you need, without astronomical price tags.

 

[Eurob]

Vegas sparky -- I wasn't thinking of a fiberglass pan. The thing I am considering is Dupont Corian like the countertops that look like marble. It is a solid resin / catalyst thing cured in an oven and weighs about 600 pounds. Thin, flimsy fiberglass is not an option.

Paul in Fishkill Plains

You don't want to know how they last in the long run in a shower , unless you do not see the difference in between a new or a dull finish .

I will not steer you towards a mud job ..... it was already being discussed and explained . I do not know what you are fishing for anymore -- installing -- you and the back pain -- a 600pounds base with your buddy .

 

[Vegas_sparky]

Paul, don't let the cat fights scare you off. I have learned a lot from the heated discussions here.

I'm just a DIY guy, renovating my own homes. You just want your shower back. I hope we can all help you better understand how these builds are constructed. In the end you will have to make the decisions as to who/how the work gets done. Your knowledge will help you make the best decision possible. You won't learn it all in a day. Learning enough to find the right guy is what you need now. As the build progress', update your thread with pictures and descriptions of what's happening. These guys here are very good, and may see important details that you, and your contractor miss.

 

[DonaldC]

Hey, a cat fight!!!! Good, I'm a Polack, I like cat fights! I sense that this one has been going on for a while here in this forum. Now, where's that popcorn.....

Ya know, some of us have worked at one job for a long time, others have moved around a lot. I grew up on a dairy farm in Walton, NY, milking 95 Holsteins morning and night. Then in 1947 I went to Tokyo for 15 months where dad was reopening the far east division of United States Lines using 118 freighters to serve 1142 island destinations. After that I went back to the farm and helped build 4 barns, 3 houses, and milked a lot of cows. Then I played guitar professionally in the 1950s working up to WABC New York and a Capital records recording contract. I was pretty good. Then I spent 7 years at Cornell, MIT, Harvard and Columbia earning some degrees in useless stuff like Physics. Then I worked at designing radio stations and recording studios. I made some really good recordings of the Philadelphia Orchestra. I finally found a steady job in Avionics Engineering at Pan Am and wound up as Vice President of Engineering. After they went broke because the war department couldn't pay for the Kuwait war transportation I rebuilt tug boats in Port Bolivar, TX.

Now I'm retired, working on my eighth decade, in Fishkill Plains. In 2005 I hired a professional mason and tile setter to build a humdinger of a bathroom. It looked great, but it didn't last because the pro with the business name on three trucks was a schmuck and the membrane leaked. So I have to get it fixed, but the present day pros, all of whom claim 30 years experience but weren't in business in 2005, each have different ideas about what I should do, and each of them thinks that only he is right.

So, I came here confused. I asked, "Now what do I do … a new mud floor … a solid molded composite insert … or a membrane over a tapered support?" Now, I don't want you guys to stop the cat fight, I like it, and I fully expect you to start aiming barbs at me now that I have given you more ammunition about being a Polack dairy farmer, but I would like to end my confusion because I have to get this shower fixed sometime this decade.

1. The solid molded composite insert would be an oven cured plastic like DuPont Corian. The only difficulty would be dropping it in place on a layer of thinset over a plywood subfloor. It would outlast my grandchildren. The problem is that it will take 6 weeks to get, I will have to drive to Rochester with a trailer behind my Suburban to get it, it will weight about 600#, and it will cost about $2800.

2. The mud floor would be a sandwich of many layers, plywood, 30# roofing felt, tapered layer of floor mud (4 sand / 1 Portland / very little water), thinset layer, then a membrane. Then the confusion starts. Some say a second layer of 1 1/2" of mud is needed before setting tiles in thinset, others say you can then set tiles in thinset directly over the membrane. Is the second layer of mud really needed with modern fuzzy membranes which thinset can bond to? How important is the skill level of the mason who places the mud because I don't think much of the guys who've looked at the job?

3. All the membrane manufacturers say you can apply the membrane over a plastic foam tapered preform, but they only make the preform in sizes up to 60" x 60" so this was not an option. Yesterday I found that USG makes custom size sloped foam preforms which key together smaller pieces. So this now becomes an option. I have asked them for prices. This would be layers of plywood, 30# roofing felt, thinset, the foam preform, thinset, membrane, thinset and tile. This seems to be the simplest way to do it, but some of you don't think it is very permanent. How permanent is it?

Like I asked originally, what do I do? Help!

Paul Lepkowski in Fishkill Plains, NY

For custom stuff try KBRS

 

[JohnfrWhipple]

.... It is a solid resin / catalyst thing cured in an oven and weighs about 600 pounds. .....

So hard to install well I think. I have almost no experience here but recently installed a solid stone base from Indonesia in a North Vancouver home. There was no way to set it perfectly in my book. In the end I waterproofed the thing from the back side and then tied the base into the walls with some Ardex 8+9 and SK25 Mesh.

Some of the pictures from that job are located here: https://terrylove.com/forums/index....id-stone-shower-base-made-in-indonesia.57857/

 

[Paul Lepkowski]

Hi guys,

I’ve about given up on finding anyone who has done a mud job around here. I’ve talked to seven contractors who all say they’ve done dozens of mud jobs but none of them could tell me how to mix deck mud. Heck, even I know that deck mud is 1 part Portland cement to 4 or 5 parts sharp sand with enough water to make it hold shape when squeezed into a sausage shape. Phooey!

Eurob -- I really don't think I can find anyone I would trust to do a mud job hereabouts. I might just have to go with the 600 pound base. With my experience as an aerospace engineer I might just use some helium filled balloons to lift it and float it into place above the joists. LOL.

DonalC -- thanks for mentioning KBRS. I already called them and found that they only do center drains. Their molds are not built to create linear drains.

John Whipple -- Hi John, thanks for responding. That stone base you installed looks heavy! The cast slab I'm talking about is totally waterproof. It would just be bedded in a layer of thin set mortar over the plywood. There would be clearance between it and the wall studs. Furthermore, the edge of the slab usually has a 3/8” x 3” high dam attached with a resin plus catalyst glue. The wall backer board is intended to be shimmed out so that it comes down inside of the dam and leaves an air gap with both the dam and the top surface of the slab. This backer board is then covered with a membrane and tile which also leaves an air gap with both the dam and the top surface of the slab. As a final step this air gap is filled by injecting a silicone caulk into it. That combination should be pretty waterproof. How are things in Vancouver? It's been 15 years since the last time I visited Stanley Park.

I had discounted the possibility of using a foam preform to establish the slope because the largest I could find for a linear drain was 55” x 55”. But, this week I finally got a response from a factory rep from USG. They make custom size foam preforms of ANY SIZE with center drains or linear drains or no drains! Their northeast distributor, Arley Wholesale in Scranton, and the local dealers, Prosource and Fitzgerald Tile had never heard of it. Shipping is no problem because it comes in pieces, just like the Schluter preform, and it probably weighs very little. They make it to order and ship it from North Carolina with a three day lead time. Furthermore, you can cut it to size with a knife on site, which means you can order it slightly oversize and trim it down to just fit between the studs which are not quite square. I have requested a quotation for a 61” x 104” foam tray with a unidirectional slope across the 61” dimension with no provision for a drain.

If the quote is reasonable this may be the way I will go. From what I read about foam tray preforms I would do it as follows.

First, I will measure the thickest part of the foam tray, calculate the height of the required joists, cut them and install them. I will use five joists spaced about 10” on center. The joists will run parallel to the long dimension.

Then I will install two layers of 3/4” plywood, with the long dimension running across the joists. The first layer will be screwed to the joists. The second layer will be screwed to the first layer, not the joists. I will leave expansion spaces between the sheets and the joints will be staggered. I will probably use fiberglass tape and thin set mortar to fill the joints in the upper layer of plywood. I will cover the top layer of plywood with 30# roofing felt to limit the plywood's ability to suck moisture out of the layer of thin set above it.

My nephew will fabricate a stainless steel linear drain 102” x 2” with a 1 inch horizontal flange to recess into the top of the foam tray, and a 2 inch vertical flange which will go up behind the backer board on the studs.

I will then dry fit the plastic tray and trim it to size leaving it 1/8” shy of the studs. Using a router I will cut a 1/8” x 3/4” rabbit along the long edge of the foam preform where it will mate with the drain. I will then apply a layer of thin set mortar to the top of the roofing felt and set the plastic tray in the mortar. The top horizontal flange of the drain will be bedded in thin set mortar in the rabbit on the top edge of the foam tray. The bottom of the drain channel will have welded brackets which will be fastened to the bottom of the plywood subfloor with screws.

I will then fit 1/2” backer board to the studs and ceiling joists. The backer board will come down in front of the vertical flange of the drain and will be bedded into silicone caulk at the drain flange. I will then tape the joints between backer boards with fiberglass tape bedded in thin set mortar.

I might decide to then apply a layer of Kerdi, USG, or Laticrete membrane to the foam tray and the corners with the backer board on the walls. I will then apply 2 layers of Hydroban or Redhand to the tray over the membrane and to the walls and ceiling. The membrane and/or the liquid coating will extend over the drain flange and into the drain channel.

Then I'll set the tile in thin set mortar directly over the cured liquid membrane.

Have I forgotten anything?

If it turns out that the quote I receive from USG for the foam tray is unrealistic I will then continue negotiations with a firm outside of Rochester New York who can make a solid surface Corian type slab. It might be time to go find some weather balloons and a cylinder of helium, and to rent a U-Haul trailer for the 200 mile drive to Rochester. I'm not going to trust that slab to a truck line!

Paul in Fishkill Plains NY

 

[Eurob]

With my experience as an aerospace engineer I might just use some helium filled balloons to lift it and float it into place above the joists. LOL.

Now there you have to use something else like sound waves , an ancient technique

My nephew will fabricate a stainless steel linear drain 102” x 2” with a 1 inch horizontal flange

There is clue why you cannot compare pricing of linear drains . I see from where the favor comes in , but he can also make you a SS shower base unit , for just dropping purposes .

I really don't think I can find anyone I would trust to do a mud job hereabouts. I might just have to go with the 600 pound base.

Hard to believe that you cannot find a veteran tile installer in your area which can do you a well mud bed as per your specifications . I just don't buy it .

I hope you get some REAL help for the project in mind . One hand I could give you from here is the advice of not closing the walls if you want to perform the drop without injuries or mishaps .

 

[Jadnashua]

You do NOT want a slip sheet on the plywood when thinsetting down the foam pan...you want to use a modified mortar, or whatever the manufacturer calls for and bond it directly to the subflooring. You'd use a slip sheet if you were doing a reinforced (non-bonded) mudbed, but this is different. They should have instructions on their website.

 

[Paul Lepkowski]

Now there you have to use something else like sound waves , an ancient technique

LOL. Might work!

There is clue why you cannot compare pricing of linear drains . I see from where the favor comes in , but he can also make you a SS shower base unit , for just dropping purposes .

He quoted $180 for me, $290 for anyone else for the 106" drain. I hadn't thought about making the whole thing out of SS. He might do it. His grandfather fabricated this balustrade and he's almost as good. http://www.4dancers.org/wp-content/uploads/2010/02/stairs.jpg

Hard to believe that you cannot find a veteran tile installer in your area which can do you a well mud bed as per your specifications . I just don't buy it .

I found a couple of older guys who could do it, but they said it's too much work. They didn't want to waste their time. They're too busy working on the developments Toll Brothers is building here.

I hope you get some REAL help for the project in mind . One hand I could give you from here is the advice of not closing the walls if you want to perform the drop without injuries or mishaps .

That's what I'm looking for .... REAL help. If you're in Montreal you could drive down here in about 4 hours. I'd be glad to hire you if you want.

I thought about not closing the walls up before I drop the monster slab, and about the helium balloons, and also about a cable block and fall to lower it. I couldn't see how I could rig cables under it to lower it. I do think I can lower it slowly with a couple of jacks down in the crawl space with pipe based supports reaching up through the stud bays.

Paul in Fishkill Plains, NY

 

[Paul Lepkowski]

You do NOT want a slip sheet on the plywood when thinsetting down the foam pan...you want to use a modified mortar, or whatever the manufacturer calls for and bond it directly to the subflooring. You'd use a slip sheet if you were doing a reinforced (non-bonded) mudbed, but this is different. They should have instructions on their website.

Good catch Jim. I thought the roofing felt would prevent the thinset below the pan from losing its water too quickly and not hydrating enough to develop full strength.

Should I just wet the plywood down thoroughly before applying the thinset?

Paul in Fishkill Plains, NY

 

[Eurob]

That's what I'm looking for .... REAL help. If you're in Montreal you could drive down here in about 4 hours. I'd be glad to hire you if you want.

I am flattered , maybe I can find you someone closer . Check your inbox.

 

[JohnfrWhipple]

....Hard to believe that you cannot find a veteran tile installer in your area which can do you a well mud bed as per your specifications . I just don't buy it .....

I do Roberto.

The US has a much smaller labour pool of skilled workers in my opinion. The worst states are California, Texas and Atlanta if my online clients are any indication....

 

[Eurob]

I think there is someone -- closer than I am -- which can really help Paul , John .

 

[Jadnashua]

Good catch Jim. I thought the roofing felt would prevent the thinset below the pan from losing its water too quickly and not hydrating enough to develop full strength.

Should I just wet the plywood down thoroughly before applying the thinset?

Paul in Fishkill Plains, NY

SSD (saturated, surface dry) is your friend when applying thinset or mortar or concrete to something and you want to promote the best possible bond. It's only too wet if there's standing water on it, but if you just give it a good wipe with a wet sponge, that does two things, removes surface dust and crud, and creates the SSD situation. THe bigger the area, the faster you have to work to prevent things from drying out or skinning over. You can use a primer like designed for slc, but for most situations, that's overkill, but it does prevent the surface from sucking too much moisture out of the mortar.

 

[JohnfrWhipple]

I think there is someone -- closer than I am -- which can really help Paul , John .

I think you need to go for a road trip and bang this out! to bad our insurance does not cover us to work in the US. This past four weeks I have turned down 2 job in the US. I need to find a loop hole around this dilemma..

I'm thinking I could charge an insane amout for a box of pencils and then go and do the other work for free. This way I'm not actually working in the US..... Hmmmmm

I might be onto something. I would love to fly down to Atlanata and Floirda for a couple weeks!

 

[Eurob]

I think you need to go for a road trip and bang this out! to bad our insurance does not cover us to work in the US. This past four weeks I have turned down 2 job in the US. I need to find a loop hole around this dilemma..

I'm thinking I could charge an insane amout for a box of pencils and then go and do the other work for free. This way I'm not actually working in the US..... Hmmmmm

I might be onto something. I would love to fly down to Atlanata and Floirda for a couple weeks!

There are some bridges I am not crossing if all the paper work is not in order .

Doing the job wouldn't be a problem , the dilemma is .

 

[Jadnashua]

You're probably not up to mixing and carting several hundred pounds of deckmud, but even if you first build a mockup and then throw it away to practice, you aren't out much money. The stuff is sort of like wet beach sand, but it does compress and pack. You do have some time to work with it, and screeds and straight edges, especially on a single slope to a linear drain is easier than trying to create a multi-sloped pan with a center drain (offset is harder on that type, too).

If you go with the preformed foam pan, just make sure that the subfloor is nice an level and do not try to make it up with the foam and thinset or you'll likely be disappointed. You do want to shuffle all around the pan after setting it in thinset to make sure it is well embedded, and to use the proper sized trowel. If you were trying to level it in that process, you'd probably lose all of the effect you were trying for and the results will be unpredictable (you cannot take the thing back up reliably to try again and even sliding it after it makes contact can be difficult if you press any part down first). It is important that the thinset is not mixed too stiff and you want to backbutter (burn in a thin layer with the flat of the trowel) on the bottom of the foam tray before setting. That little extra makes a HUGE difference in the bond strength.