HELP! He did not hot mop!

Discussion in 'Remodel Forum & Blog' started by slinkywebo, Jul 30, 2009.

  1. slinkywebo

    slinkywebo New Member

    Messages:
    9
    Location:
    San Diego
    Hi-

    I have been working on a bathroom remodel. I asked the contractor to hot mop the second story bathroom. He put down tar paper, a layer of Henry's, and a plastic sheet. Is that enough to prevent leaking? Do I need to demo the floor, hire a hot moper and redo the floor?
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,997
    Location:
    New England
    Hot mopped showers are a regional thing (mostly CA). It works, but the quality varies a lot between installers. They don't typically last as long as a conventional pvc liner shower.

    There are more than a couple of ways to build a leakproof shower. It doesn't sound like you have one of them.

    For shower contruction help, you'll get a lot more help at www.johnbridge.com. Friendly people, and very knowledgeable.

    Whatever technique you use to build the shower, the waterproof layer must be on a slope (and the tile is a decorative wear layer, not the waterproofing layer). In a conventional shower, this means a layer of deck mud (a mix of cement and mostly sand) that is sloped to the drain. Then a pvc liner that is clamped to the drain and goes over the curb. Then another layer of deck mud, then thinset and tile. The liner needs to go up about 3" above the top of the curb, so in case the drain gets clogged (or you happen to stand on the drain), it will go out the curb rathe than behind the walls of the shower.

    There are other ways to do a successful shower, but all of them have the waterproof layer sloped to the drain.
  3. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    What you describe is NOT to code or any kind of standards. A wet area...shower.....needs 3 layers of felt and HOT asphalt.
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,626
    Location:
    Cave Creek, Arizona
    tar paper

    I find tar paper shower pans when I have to repair shower leaks. I cannot imagine ANYONE still installing them, hot mopped or otherwise. But I cannot imagine the installer bringing a tar bucket to a job for a just a shower pan, either.
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,997
    Location:
    New England
    From what I understand, this is quite common in southern CA. Lots of people willing to work with the hot, smelly tar for relatively cheap. It's fast.

    Personally, I'd be leery, but there apparently are a lot of them there.
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,626
    Location:
    Cave Creek, Arizona
    pans

    There were a lot of them here in the 60's and 70's also. Most have either been replaced already, or are still leaking.
  7. Pan Man

    Pan Man New Member

    Messages:
    2
    Most people in Ca prefer a 3 layer hot mop with a protective top layer over any other liner especially a over a loose, bulgy, rounded corner, pvc liner that is prone to punctures by other contractors using them as trash cans.....:)
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,626
    Location:
    Cave Creek, Arizona
    liner

    Fold and place the liner properly, and do not install it until the tile is about to be installed, and you will eliminate ALL of those problems.
  9. Pan Man

    Pan Man New Member

    Messages:
    2
    Sounds easy....what if there's a seat? How do you stick it to the wood and create a sufficiant splash to tie into properly? What if the shower is round? If it's a large pan do you just glue two pieces together hoping your seem is water tight?
  10. bahtah

    bahtah New Member

    Messages:
    1
    Location:
    California
    The only shower pans I have ever had leak are the plastic pre-formed junk that track builders install. If you step into a shower and there is any flex in the pan, it;s going to leak. When I build my own home I had a heavy composit pan build that looked just as good after nine years as the day it went in. There is nothing wrong with Hot mop pans if the proper backing is installed and the tile work is done correctly. Most leaks with any shower pan is due to poor workmanship. In answer to your question I would say take it out and do it correctly. The hot mop is a good sealing method, on the walls use backer board and seal with Red Gard prior to any tile. The backer board needs to go down to about an inch over the pan bottom and not screws or nails should be used below the Hot Mop backing that is at least 10" up the shower walls.:cool:
  11. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,246
    Location:
    Land of Cheese
    Thanks for dragging out a forum thread from 4 years ago.
  12. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,626
    Location:
    Cave Creek, Arizona
    post

    Not quite 4 years and some people have a lot of time on their hands, with nothing else to do. Maybe the original poster was still waiting for an answer he agreed with.
  13. suceress

    suceress Member

    Messages:
    159
    Location:
    LA
    Holy thread resurrection, Batman!

    I think it was actually an interesting discussion though. I wonder what the person ever had leaks. I like to read about what methods are the best for sealing under showers and such.
  14. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,997
    Location:
    New England
    If you live on the west coast, they'd say that hotmop is the best thing going. I think that's mostly because they have access to cheap labor for the messy, stinky, way of doing things. A liner costs more in materials and requires more skill to get the preslope and setting bed in without damaging or incorrectly installing the parts. A surface membrane is (IMHO) the best way to approach a quality shower. This totally isolates the wet side from the dry side for the ENTIRE shower.
  15. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

    Messages:
    4,129
    Location:
    North Vancouver, BC
    Using Hot Mop & Kerdi or Hot Mop & NobleSeal TS

    I have two clients right now building showers in California. Both are using Hot Mop. The way your build is outlined you do not have a proper installation. Look through the link below to see some of the steps needed to succesfully hot mop your shower.

    With the two builds I/m involved in one is getting Noble Seal TS and the other is getting Kerdi DS. These products for the walls and ceilings but the floor, and curbs will get a traditional hot mop.

    What do you think is safer? - insisting that a new crew use your shower for the first time to install new products or go with a time proven system like a hot mop?

    Here is some info on Hot Mopping that might be helpful for some.

    http://www.houzz.com/ideabooks/8715503/thumbs/California-Hot-Mop---Waterproofing-your-shower

    ACO has a new clamping drain just for California Hot Mop's.

    [​IMG]

    HOT MOP can and does work well in shower construction. Look at this shower with two drains - very hard to build that with a liner or sheet membrane.
    Last edited: Jun 19, 2013
  16. suceress

    suceress Member

    Messages:
    159
    Location:
    LA
    Is the surface membrane something that is sort of painted on? Like a latex-like substance? The only thing I can really think to compare it to is the stuff I put on my barn roof that was white and thick and I used a mop to spread it. It was to prevent leaks.

    I'm wondering what recommendations are in the southern US where it is extremely humid. Does the moisture in the climate affect what moisture barriers are needed in bathrooms?
  17. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,997
    Location:
    New England
    Personally, I stay away from liquid, paint or roll on membranes. Now, if I did this on a regular basis, that may be a different story. I think it is hard for the DIY'er to get the proper thickness without getting pinholes or thin areas; excessive thickness can be an issue, too. What I'm talking about is something like Kerdi http://www.schluter.com/5288.aspx this goes on more like wallpaper than paint (it is a sheet membrane). Noble, and others may similar things. To me, this is more reliable. FWIW, Schluter gives a 10-year warranty if you use their stuff and install it properly.
  18. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

    Messages:
    4,129
    Location:
    North Vancouver, BC
    I think you will be hard pressed to find a more accepted shower waterproofing process in Southern California than Hot Mop. California is a big state and thousands of Hot Mop showers get built every month. You can improve on this installation with the use of a sheet membrane (like Kerdi or NobleSeal TS) over the mortar walls typically installed after the hot mop crew do there thing. In this improved installation the Kerdi would for example be installed over the walls and ceiling areas getting tiled and not the shower floor and curb.

    I just spoke with a women from Newport Beach who has a steam shower being built. She insisted on a three day flood test and got it preformed. Passed with flying colours and next her shower floor and mud walls get installed. After this step she plans to use Kerdi DS or NobleSeal TS. She is building a steam shower and has had found it hard to find any installer willing to improve on the Status Quo.

    JW
  19. suceress

    suceress Member

    Messages:
    159
    Location:
    LA
    Thanks, Jorhnfrwhipple. I wonder what the codes in Louisiana are and what the procedures are. I know for a fact that hotmopping was not used in any of my bathrooms. Can Kerdi be installed under linoleum and put down on top of a wooden subfloor? Or does it require more insulation than that?
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