Hot mop still the way to go in California? [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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06-08-2012, 06:28 PM
Its been awhile since i signed on here. Really like this forum i learned tons of great info and tips.

Im curious in southern cali is hot hop still considered the most leak proof way to do custom shower pans?

I remember years ago mentioning hot mop and lots of members outside of cali were like what is that???

Havnt seen in person yet but pretty sure its a standard 60" opening. The home owner doesnt want a cheap prebuilt pan that is gonna chip or crack. This is her rental apt. She wants strong and in cali we all been told hot mop custom pan is the way to go. Thats what she is asking for but im curious if there are new options im not aware of.

What you guys think?

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06-08-2012, 06:45 PM
Depends who you ask. Any of the systems will hold water if installed properly. From my experience, a hot mop will rot out in 25 years, give or take 5 years. I have yet to see a PVC liner rot out, they leak from installer error.

06-10-2012, 07:32 PM
Sheet applied membrane, liquid applied membrane. How's that for not being partial?


06-11-2012, 08:13 AM
I think for a custom shower where the hot mop shines is in the odd shape showers or larger pans where you don't have to mess with trying to glue a PVC liner together. I have also seen hot mops that have lasted 50+ years.

Tool Guy - Kg
06-11-2012, 08:27 AM
Hi Mark,

It sounds as though the hot mops you've seen last 50+ years are atypical. In your opinion, what's the expected lifespan of a properly executed hot mop?


06-11-2012, 08:47 AM
I've been in business since 1980, and have used hot mopped pans about 90% of the time. I always test all the pans before install starts. I had 2 vinyl pans that I installed leak when I tested them, both at the drain flange. Never had a hot mopped one leak, so some are 32 years old now. Hope to never do a vinyl one again. They guy I use is in Van Nuys, and he guarantees no leaks or he'll tear out tile and replace it himself.
Can't beat that! JoeC

06-11-2012, 10:09 AM
Around here, hot mopping still seems the way to go.

06-11-2012, 08:55 PM
It's all vinyl pans in my area, though u travel 30 miles south and it's a different story.

06-11-2012, 09:57 PM
I don't know much about hot mopping but this comes from a discussion on a different forum. There was some mention that hot mop can crack when installed in a new home due to settling. One poster (a contractor located in the bay area) also mentioned parking decks installed using hot mop which all cracked and rotted the timbers.

Also was some discussion about the risks of bringing tar at 425F into people's homes with the risk of spillage and setting off fire alarms and the fire service showing up etc.

06-12-2012, 05:50 AM
See, I was right, depends who you ask.:yeah:

06-13-2012, 09:50 AM
hehe....very cool thanks everyone

keep info coming if you want. curious what Mark says too regarding life span.

06-14-2012, 04:22 PM
What are the different ways to build shower benches? I read the brick monument thread. That seems pretty darn solid.

The walls of this shower are gonna be CBU. The shower pan liner is gonna be a hot mop. I believe they can hot mop up and over the bench if i build it outta 2x4 and plywood before they show up.

But them im not sure what the best way to get the shower bench tile ready without driving a millions screws through the hop mop.

Do i just press meth lath into the tar on the sides and top. With no screws or staples. Then mortar it? I can see how that works well for a shower curb because its draped over and stapled on one side. But for a shower bench the whole thing could sorta pull right off.....maybe.

What about not running the hop mop over the shower bench. But instead construct it off 2x4, plywood, and CBU on top and on the sides. It would be screwed. But then redgaurd or similar over the entire surface?

I worry about the top of the bench mostly. But i guess the niche and the bottom of the window is CBU that gets screwed and redgaurded. But they might not see as much water as the top of the bench.

Open to anything here. Thanks for reading.

06-14-2012, 04:31 PM
lately ive been using the brick method to construct benches. i used to have to deal with the plywood and 2x4 benches and i can tell you the brick method is way easier and you dont have to worry if it leaks a little cause it just goes into the shower pan liner and drains.

06-14-2012, 05:42 PM
Tony, if we string enough of these threads together we'll know by and by what you're fixin' to build, but it'd really be easier if you'd just tell us, eh? :)

One of the limitations of the hot-mop method is the same as the traditional pan liner method, there's just no good way to waterproof a wood framed bench.

That's where the "monument" type bench got its start. You build the waterproof pan in any manner that suits your fancy (and has code approval), then you construct a bench of masonry material fully within the confines of that pan.

The alternative is to dispense with the hot-mop or traditional liner and use a direct bonded waterproof membrane for your waterproofing method. That allows you to construct whatever you want in the shower using whatever materials you find convenient (again, meeting code), and then waterproof the whole of it on the inside surface.

Either method will work just fine if done correctly.

My opinion; worth price charged.

06-14-2012, 09:14 PM
Yep, if I was gonna build a seat in a hot mop application, I would have them mop the tar up the walls 24 to 30 inches behind the seat area and build the seat out of concrete blocks within the hot mop pan.

06-15-2012, 12:24 PM
Very cool guys. Maybe i should try the kerdi stuff this time around. Or the monument inside the hot mop. For a roughly 60x32" shower does anyone know which normally cost more in material? Its been a couple years but i think the hot mop was in the 150-200 range for him to come out. That could pay for some kerdi membrane.

Cx its a 25 year old 1 piece enclosure she wants removed and replaced with a tile shower. Little bench and a niche. The size and shape of the bench is not critical. Its her rental and she wants durable over extravagant looking.

I kinda like the idea of trying out kerdi on this one. But if material cost is significantly more the home owner might stick with what she feels comfortable with.

06-15-2012, 01:12 PM
Was thinking. In southern california where we know a pretty major earthquake will hit. Maybe the monument style bench has a greater chance of popping joints? Or when that sucker cures does it grasp the floor and sides mechanically very strong?

06-15-2012, 05:03 PM
not sure about earthquakes but when i built my first monument style bench i wanted to test how strong it was so i gave it a few good kicks. that thing didnt budge.

06-15-2012, 07:45 PM
I build mine after I hang the lath. It's anchored in.

06-18-2012, 06:58 PM
Rock on Davy. I watched some of hamiltons video. Man if i ever have enough cash to buy and rebuild my own pad maybe i will try floating out the walls.

Its weird though. In my brain i kinda see the paper and metal lath and mud being not as secure and waterproof and something like denshield that gets a waterproofing at the seems with a product like redguard or similar.

The pros all say floating the walls is the best (i think). But why exactly? I see the mechanical anchoring to the wall being way less solid. Pretty much just staples holding it up right? Denshield is screwed like crazy. I picture stucco walls here in california. They are cracked like a mofo. Its like a shell that is strong...but once a crack forms it just starts falling apart. What keeps that from happening on a floated shower wall?

Then when it comes to water proofing. Lets say water gets behind the tile. Wont it sorta soak into the cured mud and just stay wet for years and years? So if it does soak into the mud...hit the paper...and work its way down to the pan. Arent you left with a constantly wet wall that will smell like mold down the road?

Whereas something like denshield has a waterproof face. The water cant really soak in and rot and mold. Especially if you waterproof the seems.

Whats your guys opinion?

To be clear i have tons of respect for doing things they way its always been done. I know this is a DIY friendly site. Thats rad when people try working on their own pad. But i have to wonder is a product like denshield in existence because of the DIY buyer? Or maybe its a better way to waterproof a shower?

06-20-2012, 09:25 PM
When the other side of the shower wall is drywall. Either a hallway or bedroom. Do you just glue the cement board for the back section of the shower niche?

06-20-2012, 09:33 PM
I know a guy that often just waterproofs (piece of kerdi) right over the back of the drywall and tiles it as is. ;)
That guy doesn't want to say who he is because he is probably "wrong", but he's gonna keep doing it anyhow... :stick:

Tiger Mountain Tile Inc
06-20-2012, 09:49 PM
I thinset the cbu to the drywall.

I know a guy that often just waterproofs (piece of kerdi) right over the back of the drywall

edit: I don't see anything wrong with putting Kerdi on drywall.

06-20-2012, 10:02 PM
I do both, with Kerdi its done more.
If I'm doing HydroBan or HydroBarrier I thinset a piece of CBU on the back of it.

06-20-2012, 10:16 PM
Wow so fun to learn!! Trippin out cause i think of the 7 or so showers i have done in my life. All have had the niche to an exterior wall.

This one im looking at the niche location right next to what appears to be a fist repair from the hallway. Im thinking what if the next renter punches the wall 8 inches to the left. That would go right through my awesome spectacular super detail orientated niche.

06-21-2012, 06:07 AM
I used to work at a psychiatric hospital. They would constantly punch holes in the walls. I would repair them at night only to have them do it to the same spot the next day.

I started using metal stud pieces to re-enforce the patches.

Boy were they surprised !!!


ps I quit because I was afraid they were going to me. :oyeah:

Houston Remodeler
06-21-2012, 07:50 AM
We tiled the walls 6' up in a men's bathroom in a nightclub. Under the drywall is 3/4" BC plywood.

After 11 years the tile is still in pristine condition. I can't say as much for the fists, toes and shoulders.

06-21-2012, 08:53 AM
Interesting on the gypsum.

What cement board do you guys consider top dog?

If i went with hardi 500 instead of denshield would you recommend applying a waterproof membrane over the entire shower?

I really like denshield but i dont have all that much experience with other products. I tape the seems then redgaurd the hell outta them.

06-21-2012, 09:41 AM
Tony, the choice of wall board is entirely up to you. I can find you pros who will tell you any one you pick is both the best ever made or the worst. You pick the one you like, including DensShield, and use it per manufacturer's instructions and it'll work just fine.

My opinion; worth price charged.

06-21-2012, 06:33 PM
You are creeping on 60,000 posts. Holy majoly!!!!

Cool stuff. I love forums.

Wanna know something funny? During the day working having random thoughts. More than once i have thought "who is that guy as cx's avatar?"

He looks pissed off

06-21-2012, 06:45 PM
Whats the chance you know Jeff Tron?

You guys talk alike and both live in Tex Ass.

06-21-2012, 08:56 PM
"who is that guy as cx's avatar?"You find out, you let us know.

Got no eye-dee who Jeff Tron might be.

06-22-2012, 09:54 PM
Cool cx. So that you or what?

Couple questions i have. Want to make new threads but think its better to ask here.

Is there any negative to applying a waterproof membrane such as RedGaurd or AquaDefense to a monument style brick and mortar bench?

I just went on website and see Mapei HPG. Is AquaDefense well respected? I only have experience with RedGaurd. All im doing is waterproofing my seems of the Denshield board. Also coat the heck outta the shower niche.

Hoped to get Denshield up today but the walls are so tweaked i need to attack it tomorrow with a fresh brain. So i got time to return the AquaDefense if there is newer better stuff available.

Love hearing opinions.

06-24-2012, 10:56 AM
One of my walls was previously shimmed out 3/4 inch. I need to fill that gap before the denshield goes up.

Should i hang metal lath down my 2x12" blockers. Staped on the top only. Then use mortar?

Or just use thinset?

3/4" seems kinda big for thinset.

Hopefully the other questions get seen. Sucks cause you cant really ask general questions here without it getting moved and lost in a thread with a completely unrelated title.

06-24-2012, 12:34 PM
Tony, there is no need to waterproof a monument style bench if it's built over your water containment system, but you could do the top if you like. You do not really wanna cover the whole thing, though.

You can use any brand of waterproofing membrane that indicates it complies with ANSI A118.10 standards.

I don't understand either of your current questions. Perhaps a photo or two of your current situation would help.

We can change your thread title to something more generic any time you'd like, but the title means little or nothing to the folks who are likely to help answer your questions. They're gonna see your thread rise to the top of the queue with each new post and respond to the question at hand. If you get overlooked, make a new post to bump the thread to the top.

06-25-2012, 06:57 AM
Thats a good point. The pros who are generous enough to read and interact will prolly read the thread regardless of title.

Whats the reasoning behind NOT waterproofing the front of the bench? If built solid...and waterproof....the chance of a moisture sandwich should be zero. Again never trying to argue just asking some of the many questions i form during the day.

I forgot that i cut out the 3/4" furring strips and installed 1/2".

Stapled up some mesh and used thinset.

Is that kinda....cheesy?

06-25-2012, 06:59 AM
I cleaned up my globs of thinset on the backer board before installing. They are too high...and too wet.

06-25-2012, 07:43 AM
Thought I was confused without the photo, Tony. With the photo I'm absolutely sure. I've honestly got no idea what we're lookin' at there.

Hang on, perhaps others can see what I'm missing. :)

Tool Guy - Kg
06-25-2012, 08:46 AM
What CX said. :scratch: :shrug:

06-25-2012, 10:52 AM
My first brick bench woohoo!!
Mixing mortar is like drinking coffee.

06-25-2012, 10:58 AM
The denshield is furred out 1/2" over the shower pan.

I wanted something behind it for compression strength.

Used the lath to get me 1/4" out.

Thought might be better and would keep globs from falling down wall prematurely.

Its a tar shower pan. Direct contact with lath is ok.

06-25-2012, 11:32 AM
I was just thinking. Isn't it more an upside down chicken pot pie...than a moisture sandwich? If water got behind tile and the waterproof membrane wouldn't it escape where the pointy trowel is pointing? Does mortar flow water well enough for it to reach deck mud bed?
If I use mesh tape and thinset between bench and wall. Then waterproof would that be best way to tie it together?
What if I poke a pencil into the bottom of the mortar. Make a little water escape channel?

Edit: chicken pot pie thats been slightly eaten...missing its top.

06-27-2012, 12:45 AM
Here is where im at. Plan was to use mesh tape and thinset where the bench meets the walls. Then waterproof membrane the entire thing. But im pissed cause i didnt foresee that first row of set tiles would be blocking me from applying mesh tape and thinset to the top of the bench.

Does mesh tape and thinset really do a damn thing in terms of movement between the bench and the wall?

Im gonna waterproof the top and the front vertical. Are there any comments on all the previous questions? Why is waterproofing the side of the bench not a good idea when it can breathe...maybe..through the bottom?

I ended up poking 2 holes facing upward into the curing mortar bed for drain channels. Please tell me if any this stuff is completely retarded hehe

06-27-2012, 10:47 PM
Cool camp thanks for replying. The holes are sorta an idea i have. Lets say you are the masonry bench. Its solid but also porous. Water can travel through it to a certain extent...the amount of travel/drainage question is something i have tried asking in many different ways and cant get an answer.

To me....if you build a brick bench. And water leaks past your grout onto that bench. Its gonna turn into a mildew gross smelling bathroom. How can it ever dry out completely? By the time you even know there is a leak its already gonna be a disaster. Even if you fix the leaking section of does that brick and mortar ever dry out completely and not form moldy yuck? I hate that smell and can recognize it at hotels or friends apartments.

So my questions..and ideas are this. How well does mortar really evacuate and flow water? What if you put little channels at the very bottom layer of mortar under the first row of blocks. If i was a water droplet...slowly....very slowly making its way south. It would eventually find itself at my bottom layer of mortar. My goal and idea is that a hollow little channel would draw that water in. Even in a diagonal direction from top to bottom. Its the path of least resistance when capillary action is pulling the water toward freedom. Let the water leave the maybe overly dense mortar into the accepting less dense dry pack.

06-27-2012, 10:50 PM
whoopsie. thought i included a pic.

hopefully this works:)

say ello to my little holes (tony montana voice)