calling John Bridge. Q for him?

Discussion in 'Shower & bathtub Forum & Blog' started by rap, Mar 30, 2012.

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  1. rap

    rap New Member

    Messages:
    63
    Location:
    california
    Hi John, i didn't know that you posted on here. I'm standing at attention as i type.
    My question refers to my earlier post ref. the Palo Alto Bldg Dept ruling ref banning drywall in wet areas. (The post is a little down this page.)
    Do you have any suggestions for a secure backing for floating a S&C coat for tile in eg. showers etc. without using drywall.
    A two-coat float over mesh and 15lb felt is my two cents worth.
  2. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    4,122
    Location:
    North Vancouver, BC
    The City of Concord, California tile backer board options - code requirements

    Standing by for the Orange Kool-Aid.

    This I got to hear.

    Please John Bridge tell us how your little label on Kerdi will trump Tom's building department?

    I can't wait.....

    Tom what city are you in. I'm going to call and speak with the city inspector just as a double check for you. I do love my calling plan!

    While we wait for John to chime in here is some resource information for you.

    Letter of approval for Hardie Board from the city of Los Angeles - http://www.jameshardie.com/homeowner/pdf/larr24862.pdf

    This list of requirements from The City of Concord - http://www.cityofconcord.org/pdf/permits/building/bathroom-remodel.doc

    Wetwalls:
    Moisture Resistant Gypsum Board (blue/purple board can be used for solid surface materials only)
    • Backing that is permitted to be used as a base for wall tiles and panels in showers are covered as follows:
    • All products must extend at least 70†above the drain inlet.
    • All products must comply with ASTM C 1178, C 1288 or C 1325.
    • All products must be installed in accordance with the manufacturer’s installation instructions.

    So no drywall in this list for tile - shocking. The requirements C1178, C1288 and C1325 do not list regular drywall. These references are for denshield like products and cementious products only.

    A. Fiberglass Mat Backer Board – (DensShield, GlasRoc or other approved products)
    • Do not install a water-resistive moisture barrier behind Fiberglass Mat Backer Board.
    • INSPECTION: Required after completion of taping

    I love this. California is so ahead of the nation. Mine and yours. Inspections for backer boards I love it. Note that California does not want a water - resistive moisture barrier behind the fiberglass mat backer board.

    B. Cement and fiber-cement Backer Boards (Hardi-backer, Glas-crete, Durock)
    • A water-resistive moisture barrier is required behind cement board (such as 15# roofing felt or Grade D building paper).
    • INSPECTION: Required after mesh tape is applied.

    Note that California does want a water - resistive moisture barrier behind cement board.

    C. Original Mortar Backed Ceramic Tile (Lath and plaster)
    • A water-resistive permeable barrier with a performance of one layer of No. 15 asphalt felt, or Type 1 felt or other approved materials is to be installed behind lath.
    • A water-resistive permeable barrier with a performance of at least to two layers Grade D paper is required behind lath applied over wood base sheathing.
    • INSPECTION: Required prior to mortar application.

    No drywall for tile - anywhere. And since you need an inspection before covering with mortar there is no way to sneak Kerdi in over drywall!

    JW
    Last edited: Mar 31, 2012
  3. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    4,122
    Location:
    North Vancouver, BC
    City of Palo Alto - shower backer board requirements - no drywall allowed

    The city of Palo Alto in California has a wonderful report on shower inspections and their code requirements.

    [​IMG]

    [​IMG]

    Picture Source

    I think Jim and John Bridge should forward this email to Schluter Systems.

    Here is a link to the nine page document. http://www.cityofpaloalto.org/civica/filebank/blobdload.asp?BlobID=17678

    In California I believe you need a 30 or 40 mil liner for showers.

    In a tremor would you rather trust a 40 mil liner, a 30 mil liner with flexible sealant or a 8mil liner set with sand and cement?

    For reference look at your credit card. That is 30mils or 30/1000" thick. Now imagine you can slice that card into three slivers - Each of those slivers would be thicker than the liner that makes up Kerdi.


    In california you must have normal sized showers like us here in Vancouver. Kerdi is sold in 3' wide rolls so you need to seam a shower floor (to wrap up the curb and add a few inches a kerdi shower needs to be less than 20" wide to avoid this). Your hot mop floors are seamless. Noble Seal TS is sold in 5' rolls and Noble deck in 6'. Most rubber liners come in 5', 6' and sometime 7' widths.

    If you have a tremor, do you want a seam at the bottom of your brand new renovation?

    I wouldn't.

    JW
    Last edited: Mar 31, 2012
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,995
    Location:
    New England
    Kerdi is a meter wide - close, but more than a yard (39.37").

    Kerdi band makes perfectly good seams anywhere, and it's easier to not wrap it around corners, but butt it, and use Kerdi band. You can, if you wish, and being thinner, can make a sharper corner than the thicker stuff, or overlap it without the Kerdiband, if you prefer. Lots of showers get built with Kerdi in CA and get inspected.
  5. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    4,122
    Location:
    North Vancouver, BC
    City of San Bruno says no to drywall in showers

    Whoops sorry Jim. So you could build a kerdi shower 23" wide with out having a seam.

    I'm thinking most people would rather have a nice 36" or 48" shower like we build them up North. No seams in the floors at all.

    If you had an earthquake and the home moved a bit I think those Kerdi seams might bust free, I'd rather trust a old school linear and poly behind cement board than Kerdi seamed with non-modified thin set.

    I helped with a project in California and we specified it with Noble Seal TS. But that is 5' wide so like a hot mop the entire floor was done with one piece of membrane.

    Not rocket science. In Europe Kerdi is only used for walls and a thicker membrane Kerdi DS is used for floors. I think that comes in 6' widths if I'm not mistaken.

    In California I'd be using a single sheet membrane on the floors and bringing that up the walls, lapping over with Poly, Boarding, and then waterproofing the board for good measure.

    Or hey you could listen to the advice of men who sell Kerdi for a living and just go against building codes and use drywall and an "Uber thin" membrane that needs to be seamed everywhere!

    [​IMG]


    Yes and none of those inspected showers have drywall in them since California inspects the backer board before installation of Kerdi.!




    JW
    Last edited: Apr 1, 2012
  6. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Any specs on shower floors do not have to do with earthquakes. If we have the big one, you will be worried about whether your roof is still up...not whether you have a crack in your shower floor!!!!
  7. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    4,122
    Location:
    North Vancouver, BC
    Jim we have felt a few tremors even here in Vancouver and we are waiting for the big one. Any movement or shifting of a home will stress the shower assembly. In a large custom shower I would not want seams in my shower floor. If I wanted to use Kerdi I think I would be importing a roll of Kerdi DS from Germany!

    Kerdi DS is 22mil thick, almost three times the thickness of regular Kerdi.

    Floor movement can also come from deflection issues. If your subfloor flexes on a sheathing seam your Kerdi seam could rip apart. It is important to back framed properly around the drain and anywhere you plan to tile. Often these back framing changes do not get made and this presents a very weak point near the drain.

    I have never seen a Hot Mop install nor have I even touched it. I do know they have a very long proven track record but I was told last year that there is a study being preformed to see if the Hot Mop process is causing health issues. Not sure I would want a roofing tar like substance in my home. I have some but it's a torch on on my upper exterior deck.

    [​IMG]

    JW
    Last edited: Mar 31, 2012
  8. rap

    rap New Member

    Messages:
    63
    Location:
    california
    Thank you all for replying to my question.
    I had read the Palo Alto site recommendations before i posted. Because they are so comprehensive and detailed. I used Palo Alto as an example instead of other similar,local codes.
    However, as in my earlier question on this matter, i'm no further ahead - any advances on a 2-coat float over mesh and a barrier?

    AAMOI: i've seen hotmop pans installed and and tested, and i've demo'd other hot-mops after many years of effective use - they have redundancy/malleability esp. for tremors. They certainly lasted better than sheet copper pans.
  9. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    4,122
    Location:
    North Vancouver, BC

    Tom could you not use a product like Green EBoard or Hardie Board in 1/4" sheets? Perhaps have the hot mop done. Install a layer of building paper or felt, maybe even poly lapping over the hot mop. Install 1/4" Hardie Board or Green EBoard and then start the scratch process.

    Hardi Board and Green EBoard are both fire and bug resistant.

    http://www.facebook.com/pages/Hot-Mopped-Shower-Pans-Hot-Mop/353567278409 Here is a facebook like to a fellow in California that specializes in hot mopping. Why not message him and ask a question?

    Good on you for researching the proper facts. To many people look for an easy way out and the path of least resistance. Your shower will be a gem.

    JW
  10. rap

    rap New Member

    Messages:
    63
    Location:
    california
    John, thank you for the info. Thing is, I'm looking for something that i can staple "chicken wire" to, and then float over - neither of your suggestions will fit the bill.
    As regards hot-mop, the pan is not the issue. I'm perfectly satisfied with a conventional pan liner ( but i certainly dont put down the hot-mop method, and think it good that the skill is still carried on).
  11. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    4,122
    Location:
    North Vancouver, BC
    Tom I have only done limited floating work and it's all been exterior stucco repairs but the "Chicken Wire" is not "Chicken Wire" but "Stucco Mesh" I would imagine that there are stand offs keeping the wire off the backer board some how. If you where to use some tile shims the U shaped kind I bet you could fasten the wire to the backer board with screws not staples.

    Try reaching out to Derek Bingham 2nd TILESETTER at COASTLINE TILE INC. Greater San Diego Area. He is a member over on the Link'din NTCA cite and an old school setter. He might share some of his knowledge with you.

    Good Luck.

    Let us know the results of your quest.

    JW
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,995
    Location:
    New England
    Where do you get 23"? If your personal requirement is no seams, to maintain the required overlap, if you folded the stuff up at the edges, you'd have 35.37", or maybe a little less if you wanted a larger overlap. But, most people don't fold it around the corner and use KerdiBand, so you'd have the full width. Plus, a seam is perfectly acceptable.

    If you have movement or deflection issues, then the structure is not built properly and shouldn't be tiled in the first place. Pulling the sheet membrane along its lenght, it's pretty strong, will stretch a little bit, plus the fleece will provide a small amount of give. Once installed and covered with tile, it's quite robust.
  13. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,995
    Location:
    New England
    No idea on the specs of the Kerdi DS...my guess is it's the same width. Trying to take one sheet and bond it across all of those angles just isn't necessary...that's why they test it with the overlap seam. You can decide to make your curb out of lots of different materials, bricks, pavers, 2x material (appropriately covered for tiling), so there's no requirement you have to use their curb, nor their preformed pan material. Bigger sheets are harder to install...probably not an issue for someone who does it on a regular basis, but is a consideration for a DIY'er with one or maybe two showers in his resume.
  14. John Bridge

    John Bridge Mudmeister

    Messages:
    49
    Location:
    Houston, Texas
    Hi Tom, :)

    I worked in L.A. County back in the early seventies and haven't worked there since. All the showers I did were inspected prior to mudding, and they were one-coat over drywall or old plaster walls. I do believe drywall can still be used as a backer for a mud job, since it is covered with tar paper and lath. Their real worry is that tile not be applied directly to drywall. I know nothing about the Bay Area, but I would imagine it's the same.
    Last edited by a moderator: Apr 13, 2012
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