Hotmop - Why? (Newbie Q #1) [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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06-06-2009, 09:30 PM
Hello everyone,

I'm a newbie who's been learning a lot this evening browsing through your advice and comments. I'm embarking on a bathroom remodel in a house that was custom built in 1959. My tiler wants to bring in a hotmop company for the shower. I understand that's common in Southern California, but we didn't use this method where I've lived in other parts of the US. Can someone please explain to me what the pros/cons and reasoning is behind hotmopping? One big con I've heard about is the smell, smoke, and mess. Is there a big pro that outweighs this? Do I have to do this? Are there equal or better methods to use?

Thanks for any input. Cheers.

PS: I'm posting a couple other threads with related, but different, questions. Sorry for monopolizing people's time, but I feel I finally found a place with folks who could really help. :)

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06-06-2009, 09:45 PM
The site prefers you keep all questions on a project in one thread.

I've never done (or seen, except in pictures) a hotmopped shower, so take that with a grain of salt...

My guess is that you could do one quicker, and the materials are cheap. Deck mud is cheap too, but it takes longer.

My preference would be to make a Kerdi shower see Faster than a traditional shower, and your shower becomes 100% waterproof all over, rather than just in the pan.

06-06-2009, 09:50 PM
Never seen one either. But I thought they claimed it was because of earthquakes. It's probably because "That's the way I've been doing it for 40 years now and ain't never had a problem."

06-06-2009, 10:08 PM
Nothing but hotmops around here. My guess is they've been doing it that way forever and won't change. It aint cheap either, plus you gotta schedule it in and wait for the guy with the tar. Done correctly, it'll last for decades.

06-06-2009, 10:16 PM
The site prefers you keep all questions on a project in one thread.

Thanks...I didn't know that.

Thank you all for the input. What do I have to do if I want to skip the hotmop and I don't decide to do a Kerdi shower?

06-06-2009, 10:24 PM
There certainly are other methods you could use, but you may want to check your local codes before you decide on one.

06-06-2009, 10:25 PM
It's a California thing, I've tiled over many of them.

They won't last as long as a PVC pan. If there is a preslope under the hot mop, that will help them last longer but I have seen them rot out in 20 years, but sometimes they will go alot longer.

They do cling to the wall better helping out some but a PVC pan that's installed right is hard to beat. :)

06-06-2009, 10:32 PM
I would like to see like a remodel in a high rise condo say on the 15th floor that is completely furnished with expensive carpeting ect. ect. and see how in the world they get hot mop in a small bathroom shower without making a mess of the place, fire alarms going off, residents complaining of smell...............

What do they do, take the machine with that stuff boiling up the elevator and through the unit??????????

Sounds like a nightmare!

06-06-2009, 10:41 PM
Good point, Ben. That's probably when they would go with PVC or another type pan. All pans in California aren't hot mop but most are.

The tar pot will stink up the whole neighborhood too. Everyone knows when they are around. Kinda surprising that the state of California would allow that, being like they are.:shrug:

06-06-2009, 10:57 PM
I was thinking the same thing about that state supposed to be all ecco friendly and all..................

06-06-2009, 10:58 PM
Ben...that's exactly what I was thinking. Even a second floor in a home would be a problem for a sloshing tar bucket. for being eco-friendly...they say out here that PVC is worse than tar for the environment. I'm not sure about that.

As far as I know, there aren't any codes saying we have to use hotmop. My tiler says they'll preslope before they hotmop. I'll check if he's is willing to go with a PVC pan because, as most of you, I think it's better (and no mess or smell). I hope my guy knows how to work with one.

06-07-2009, 12:17 AM
What do I have to do if I want to skip the hotmop and I don't decide to do a Kerdi shower?

Biggest issue here is are you doing it legal and getting a permit?

If you aren't getting the correct permit and inspections-->then you can do it any way you feel like doing it and gamble you don't get caught.

If you are getting the permit and inspections, you can still use systems other than hotmop (Kerdi, Wedi, Hydroban, HPG, PVC liner, whatever). Key is getting in touch with the folks from the city and get them on board with whatever system you plan to use. DO NOT pull a permit, then decide to build it however you want,.. then have the inspector show up and try to show him a shower system he's never seen before. This can turn ugly. :bang:

What city are you in Deca?

06-07-2009, 01:17 AM
I'm in San Diego County. For what I'm doing, I was told I don't need a permit. But, I still want to do things properly. I'm redoing this bath because the original shower, built in 1959, was not built to modern standards and leaked badly. I want to rebuild it and the bathroom floor as soundly as possible. I don't want to do this again for at least 20+ years!

My goal is to find a way to do it right without having to go through the hassle, mess, and smell of hotmopping. The options eveyone's listed have been helpful. I'll approach my tiler to see how flexible he is on the hotmop.

06-07-2009, 02:07 AM
For what I'm doing, I was told I don't need a permit.

I bet the building department where you live would disagree if they saw the extent of your project :)

Up side though is you can use whatever method you like without having to convince the city it works.

06-07-2009, 06:22 AM
Besides PVC; the other option would be CPE. Similar product but different chemical composition. Supposed to stay flexible I beleive. Also made(?) by our freindly neigborhood company called Noble.

06-07-2009, 02:48 PM
Scuttlebttrp: Thank you! I hadn't heard about CPE before. I'll check into it.

For what I'm doing, I was told I don't need a permit.

I bet the building department where you live would disagree if they saw the extent of your project.

Sorry, looks like I wasn't clear enough the first time I answered your question. I asked them. I don't need a permit. I'm not trying to run around any rules. I came to this forum because I'm trying to understand the correct way of doing things on my project. One advantage of needing permits is that the building inspectors are resources for information on how things should be done properly. Since I don't have that safety net, the responsibility is on me to make sure I don't make rookie mistakes.

06-07-2009, 02:59 PM
Normally, a tearout, replacment requires a building permit. In some places, even changing a faucet requires a permit. I find it hard to believe a tearout and replacment doesn't require a permit. ARe you going by what the installer told you, or from asking the biulding department? Installers often say no permit is required...and often, they're wrong.

06-07-2009, 09:48 PM

I didn't mean to come off like the permit gestapo. I've done plenty of things that technically should have had a permit but didn't. I'm just giving info, not judging or giving you grief.

I have just seen folks that think they don't need a permit get in lots of trouble if they get caught without one. In April I saw the inspectors require an entire shower get torn out (all finished except for grout). The homeowner then had to cough up $900 to get the stop work order released so they could re-build it from scratch.

06-08-2009, 11:04 PM

No worries. :) I didn't think you were acting like the permit police. I was writing in the early hours so I figured I wasn't being clear.

I posted another question a while ago and someone said I have to put all questions in one thread. Can I ask my other question here now?

Hotmop Update:

We hotmopped today after all. It wasn't the big mess or smell I was worried about. It was quick and relatively odor free. We're doing another bathroom after this one, so we decided to hotmop this one and use PVC in the next one. Our little in-house test...time will tell which lasts longer.

Thank you everyone for your input!

06-08-2009, 11:17 PM
Glad that worked out. A good hot mop guy is pretty impressive to see in action. Fast, efficient, and can keep stuff clean.