Bathtub installation -- order of installation (end pony wall, tub, heated floor)?

Discussion in 'Shower & bathtub Forum & Blog' started by jch, Jul 10, 2011.

  1. jch

    jch New Member

    It took me a long time to get the rest of the room ready, but I finally installed NuHeat heating cables this week and passed my electrical inspection. Really nice system to work with.

    Then this weekend I rolled on Mapei Primer T onto the exterior-grade plywood subfloor (goes on pink, but dries clear -- very cool); stapled down Mapelath plastic lath; then poured 1/2" of Mapei Novoplan Easy SLC.

    Thank you all for your recommendations so far--beautiful results. Floor is now true and level -- less than 1mm (1/25") gap when checking with a 4 foot level.


    Which brings me to the question about the next step... the decoupling/anti-fracture layer (as specified by the TCNA's handbook):

    I've been so pleased with the Mapei products I've used so far (Primer T, Mapelath, and Novoplan Easy) that I'd like to try staying with them for the decoupling layer. Called their Tech Services hotline but they said they don't sell anything similar to Schluter's Ditra.

    Looked on Mapei's website for 'Crack and Sound Membrane' but found quite a few products that have that in their description:
    - Mapeguard 2 sheet membrane,
    - Mapelastic 315,
    - Mapelastic AquaDefense,
    - Mapelastic CL, and
    - Mapelastic HPG.

    **Are any of these the product you're suggesting??


    I've bought Mapei AquaDefense for the shower walls but haven't installed it yet -- thanks!
  2. johnfrwhipple

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

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    Location:
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    Mapelastic HPG - nope
    Mapelastic CL - ? never used it can't say
    Mapelastic Aquadefence, I'd rather use a sheet membrane over fresh self leveler
    Mapelastic 315 - might be an option but this stuff is hard to work with
    Mapeguard Crack and Sound is the way to go. I see many tile pros using this over the self lever coat. You will need to take care priming again and rolling out the product. If your not in a rush let that self lever cure a good week. There is little forgiveness in install this membrane so if you go side ways it's better to abort and add in a seam. I have seen loads of it installed but never once installed it myself. You need a 100 pound roller as well to install this sound and crack membrane.

    A lot of tile men are switching to Noble Seal TS for this type of application. In either install you will have overlapping of sheet seams. Installing a sheet membrane over such a large space is no hard but should be done with a helper. We did my deck in Noble Deck and troweled on the thinset and rolled on the Noble Deck in one go keeping the thin set fresh and routinely checking the coverage rates.

    As for the Aquadefence on the bathroom walls you will love this! How many square feet of wall and shampoo niche space do you have? How much Aqua Defence did you buy? Do you have a plan for the tile flange on your tub? Ideally your backer board laps this but most times the board is installed above it? Have you seen the detail we use for these type of installs? Did you get any of the fleece reinforcing mesh? What type of backer board are you going to use?

    JW
  3. jch

    jch New Member

    Thanks -- I just called Mapei's Technical Services again to double-check on cure times/compatibility etc. They echoed your advice:

    Mapelastic CI is the cheaper version of AquaDefence. Offers Crack Isolation, but not waterproofing. AquaDefence provides both. They said AquaDefence would be the easiest product for me to put on the floor (2 coats rolled-on).

    ** I'm unsure whether to use reinforcing fabric on the floor. Reminder: I'm using 12" x 24" porcelain floor tile.

    Mapelastic 315 is trowelled-on and was not recommended for a DYI'er like me. They said it's usually used over cracked concrete floors.

    Mapeiguard 2 sheet membrane was their top pick for crack isolation, but said it was harder to install than a roll-on.

    Mapelastic HPG is their older version and has been replaced by the newer types (above).


    I've already installed HardieBacker 500 over top of vapour barrier plastic in the tub area. The HardieBacker overlaps the cast iron tub's flange (shimmed it out) and stops about 3/16" off the tub deck. The vapour barrier is hanging out below the HardieBacker into the tub for now. I was going to roll-on AquaDefence down the walls and along the underside of the HardieBacker edge, then trim the plastic flush, and fill with silicone caulking.

    I have 1 gallon of AquaDefence to cover the tub surround area and slanted ceiling. It's about 69 sq ft of surface area (walls and ceiling) so it'll be close. I don't have any reinforcing mesh for the corners yet. Still debating whether it'll be necessary (or make the wall too uneven in the corners) since I'll first used fibreglass mesh and thinset in the corners and on the HardieBacker seams.

    Advice?
  4. jch

    jch New Member

    i just checked on buying some Mapei Mapeguard 2 anti-fracture membrane. Turns out the places in town here only sell it by the entire roll -- enough for 225 sq ft -- overkill for my 40 sq ft bathroom...

    They sell Schluter Ditra by the foot, but then there's the whole issue of using unmodified thinset to set my 12x24" tiles -- not good.

    Haven't been able to find anyone local who sells Noble TS yet :-(

    Which leaves me (for now) with Mapelastic AquaDefence to use on the SLC floor. Since I originally posted, random hairline cracks have appeared on the SLC (now 3 days since pouring). The cracks are random and do not seem to coincide with any seams/joints/joists so I'm assuming that it's just a result of it drying... (?)

    Do I need to use any reinforcing fabric when I put AquaDefence down on the SLC floor?? This recent appearance of fine cracks has me nervous...
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    A good unmodified (dryset) thinset will have in the order of 250-300#/sq in of bond strength to porcelain...how much do you really need? On a 12x24" tile at the lower end, that's 36 TONS to break it off. The Ditra and the floor and the house will fail long before that happens. Also, think about this: a good porcelain has an absorbtion rate of less than 1%, the waterproofing material (be it Ditra or some other membrane) is less than that. Where will the moisture go that needs to evaporate so the modified mortar can properly cure? A good dryset doesn't need to dry, only cure, and it will do that without any help inside of a plastic bag, let alone between two impervious surfaces.

    If you really must have a modified, and want to use Ditra, if you call, they'll likely tell you you can IF you use a rapid set...not something a DIY'er should really consider, though. Laying large format tile is tough to get them perfectly lush and level - even the slightest inconsistency will result in a corner being low or high - the size amplifies any small error into a huge one with that size tile. You may want to consider something like the TLS or LASH leveling system.

    Both porcelain and glass tile have been used for centuries...long before modified thinsets became available. Yes, a modified is stickier, probably has a longer pot life, and may be stronger, but there are tiled floors that are centuries old that have stood the tests of time without it.
    Last edited: Jun 19, 2012
  6. johnfrwhipple

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

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    Location:
    North Vancouver, BC
    You got me in a pickle.

    I think it's best to put the brakes on the job and see what the self lever does. If it continues to crack badly and you end up with de-bonding it could be a "Do Over".

    For starters I would not depend on the Aqua Defence as a crack isolation membrane without the fleece. I would not install the Aqua Defence over the self lever until that has fully cured which could be in a couple weeks. I would in a heart beat use Ditra over this and have done this type of application for years with not a single call back. The procedure to install the 12"x24" tile over your Ditra would be like this;

    1). Pre-Fill waffles with non-modified thin-set (let dry overnight at least)
    2). Scratch on non-modified thinset in a small area (say 1'x4') (1/4" x1/4" square notch trowel)
    3). Drop on a small layer of mortar mix (perhaps a 1/4" of material)
    4). Scratch on Non-modified thinset to the tile (1/4" x1/4" square notch trowel)
    5). Drop over mortar mix and beat in with rubber mallet
    6). Repeat

    Here is a look at some 1'x2' Travertine that my setter installed for me. There is Ditra under that tile.

    [​IMG]

    [​IMG]

    [​IMG]

    Here you can see my setter using a White Non-Modifed Thinset and the Mortar Mix. Learning how to fluff the mortar mix and how much to use takes a little practice but after setting 3-4 tiles you will be on a roll. The mortar mix supports the tile while the thinset cures. Do not be afraid to beat the tile into position - you are after 80-95% coverage for a solid install.



    I would use this approach over any levelling clip. Schluter Systems prefers the use of Ardex setting materials with their products and if you use Ardex with Ditra you can get a ten year warranty. I have been told in the past Grani Rapid is fine but to not use the liquid. This makes no sense to me since Mapei says you have to use the liquid to mix grani Rapid. Ardex is available here in Vancouver if you want to cover all your basis.

    Noble Seal TS would be a great option and allows for modified thinsets and is a true crack isolation membrane - If you need only 40 square I could sell you that off my roll or you can order direct from Noble Company. I'm placing a new order next week, if your not in a rush you can piggy back on my order. Remeber Ditra is not a crack isolation membrane and will not help you there. What it does do is cover up all those little hairline cracks with one big orange band aid and lays down easier than installing a sheet membrane.

    Tough call. The safest play at this time is to wait. Finish the tub surround and play it by ear at this point. Can you send some pictures of the floor?

    JW
    Last edited: Jun 20, 2012
  7. jch

    jch New Member

    Wow.

    Here's what the floor layout looked like before the pour:
    IMG_3933_small.jpg

    This area has hairline cracks that don't seem to align with joists nor with wires or any other discernible structure:
    IMG_4034_small.jpg

    Here's a close-up of some hairline cracks that have formed near the toilet drain:
    IMG_4036_small.jpg

    This Novoplan Easy SLC pour was done 3-1/2 days ago. The SLC is 1/2" thick on: exterior 3/4" plywood, 2x10 joists on 16" centers, 8 foot spans (better than 1/800 rating); primed first with Mapei Primer T; mapelath stapled every 2-4".

    Do these cracks looks severe enough to worry about (at this point)?? Knocking on the floor it sounds solid.
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Location:
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    Can't tell for sure, but did you use some foam around the obstructions and wall? You can't pour it directly against unyielding structures - it needs to be able to expand and contract. Same idea as not grouting tile tight against a wall or other solid thing.
  9. jch

    jch New Member

    Yup, 1/2" foam around the entire perimeter of the pour, plus 3 wraps of foam sill-gasket around the toilet waste pipe.
  10. chefwong

    chefwong New Member

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    JW -

    Interesting read on the combo you use....unmod and then mortar mix and then a good 'ole fashion hammer I suppose. Back when I did not know all the TCNA rules.....I leveled a room with Lati. 254 as thick as 2" .....just using thinset and a rubber mallet. It has had cordless batteries drop 7 feet high at least 4 times, etc - and the floor and tile are still intact !
  11. johnfrwhipple

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

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    I like to punch the tiles with my fist, hit them with the palm of my hand or use the rubber mallet what ever beats them into the mortar mix and yields me solid coverage.

    JW
  12. johnfrwhipple

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

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    I have not seen the Mapelath go in at the same time as the self levelling stage before. Whose idea was this? Did Mapei recommend it? Is the Mapeilath installed the right way up?

    If your self lever has been installed for a few days and sounds "solid" when tapped you should be OK. Perhaps call Mapei - one of their new reps lives in Victoria and was a setter for years, I'm blanking on his name.

    Some times when you get cracks like this it is a sign of over watering the self leveller.

    You might wait another four days and try one of my rules for tiling. "Never tile anything you can't hit with a hammer". If you give a few well placed blows to the floor (in between heating wires) and you don't blow away your prep or your prep work doesn't crumble it should be OK.

    JW
  13. jch

    jch New Member

    I tried to follow the TCNA 2011 Handbook and Mapei's Technical Data Sheet as closely as possible.

    TCNA specifies the following when installing Interior Floors with Radiant Heat over Wood (RH140-11, p. 103):
    TCNA RH140-11.jpg

    Mapei's Technical Data Sheets also recommend installing Mapelath before pouring Novoplan Easy:
    http://www.mapei.com/public/CA/products/NovoplanEasy_TDS_EA.pdf
    "When applying MAPEI underlayments to plywood flooring, mechanically fasten MapelathTM or diamond mesh on top of the primed surface (meeting the requirements of ASTM C847) before application of Novoplan Easy. Refer to the current Mapelath TDS for installation instructions."

    The Mapelath TDS says:
    http://www.mapei.com/public/CA/products/Mapelath_TDS_EA.pdf
    "1. Install Mapelath over the primed plywood or OSB. The lath should have a 2" (5 cm) overlap at all seams, stapled flat and uniformly.
    2. Apply a MAPEI self-leveling underlayment at a minimum thickness of 3/8" (10 mm), completely encapsulating the Mapelath. Reference the TDS for the leveler to be used and for in-depth application instructions."

    and "Lay out Mapelath over the substrate ridge-side down. Cut to fit." which is what I did.


    Novoplan Easy's TDS says:
    "Into a clean mixing container, pour the required amount of cool, clean potable water. If available water is not cool, chill water to 70°F (21°C). Add Novoplan Easy powder while slowly stirring. Mix water and Novoplan Easy powder to a mixing ratio of 5 to 5.28 U.S. qts. (4,73 to 5,0 L) water per 50-lb. (22,7-kg) bag of Novoplan Easy. The mixing ratio must remain consistent. Do not overwater material."

    I measured 5L of cool water into each bucket (with a measuring cup!) and used a timer to make sure I didn't mix it beyond 2 minutes so should be in the right range. It was a cool rainy day though (about 60% humidity) so that may have been enough to push the water content over the edge.

    I called Mapei again and they said it should be pretty much done shrinking by now (4 days) and that the cracks (too small to fit a piece of paper into) should be fine if the floor feels solid (which it does), but I should put an anti-fracture membrane down (as you folks have recommended).

    It's just a matter now of choosing which one.
  14. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    The lath is there to strengthen the slc...so, it must get installed before pouring. WIth a 'normal' concrete slab, you want your reinforcement in the middle, but that isn't what's called for with slc where it should end up with intimate contact because of the viscosity of the material, fully encasing it.
  15. johnfrwhipple

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

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    Well this is a good thread.

    If you have the lath installed and it's solid you would think that it is going to add a ton of strength to this subfloor. But the fact we have hairline cracks is cause for perhaps another step.

    I'm thinking you should just go with the Ditra or wait for my next Noble order to arrive. I'm ordering another roll of Noble Seal TS and a part roll of Noble Seal SIS for a sound proofing job I'm working on.

    If you want a part roll of the Mapei Sound and Crack I'm sure my friend Kip can sell you some - he uses it all the time.

    I have to say John you are doing a great job of showing up most pros with your attention to detail - nice work. Thanks for sharing!

    JW
  16. jch

    jch New Member

    Mapei said that the hairline cracks are probably not all the way through the pour--just on the surface. There is definitely no visible change in crack width when I bounce my full body weight near them. My guess is that the hairline cracks are from having slightly too much water in the mix--I used the upper end of the prescribed range but it was a super humid day. The cracks didn't appear until day 3--long after most pros would've started tiling.

    That said, I agree that a crack-isolation layer would be wise. Ditra is available locally by the foot so I think I'll go with that.

    Question: Which specific thinset should I use to attach the Ditra to the SLC? Over wood I know I would use a modified thinset, but over SLC I'm not so sure. Locally I can get Mapei and Ardex products. Just not sure which specific version is appropriate.

    Thanks again for your help.
  17. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    If you don't have it, download the Ditra handbook from the www.schluter.com website. It gives you all you need to know about installing it over all acceptable substrates. It's a good reference to have.

    From page 9:
    Setting and Grouting Materials
    Unmodified thin-set mortar – ANSI A118.1

    You want a premium quality dryset mortar, not the ecomony price leader in the line.



  18. johnfrwhipple

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

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    You have gone this far with the Mapei line of materials. Why not use their Kerabond setting material. If you buy some Keralastic you can mix up some modified thin set for your tile install over the Aqua Defence.

    http://www.mapei.com/public/CA/products/Kerabondkeralastic_TDS_EA.pdf

    Using a plain non-modifed thin-set it is important to note that they take a longer time to get a good bite. Do not set the Ditra and then tile the same day. Any checking of coverage will cause a suction effect on the Ditra and could cause a bond failure as the Ditra is pulled off the self leveller.

    Better be safe and set the Ditra and then let it cure out a good couple days. I've layed a lot of Ditra with modified setting material and do so at my own risk, knowing that Schluter does not allow or warranty this work without written permission from head office. If your in a hurry and I don't think you are then finsih the floor with Ardex setting materials from setting the tile to grouting - this will allow you to use premium modifed thin sets and even double your warranty if you use the right products.

    Kerabond is a great non-modifed thinset. I spoke with a top tech at Schluter some time back and he suggested using 'White' non-modifed thinset. I can not remember the entire conversation but I believe that white thinset is a better quality than grey when comparing apples to apples. I have followed this advice and when working with non-modifed thinsets prefer the white for my bonding applications.

    Kerabond is sold in white and gray. Next time I see my rep I'll ask him if he knows if one is stronger or better than the other.

    Good luck.

    JW
  19. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    In a class I went to, they said that the reason white thinset was more expensive (often a buck or two a bag) is that to get it white, they have to use cleaner, higher quality sand and components. Now, I don't know if it is actually stronger (never compared the tech data sheets, and don't know if they even are different), but by using cleaner, better sorted materials, it likely is. Unless you are planning something like black grout, white thinset tends to work quite well for most anything.
  20. johnfrwhipple

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

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    Jim I also think it has something to do with "Fly Ash".

    It appears that the cement industry is using more and more of this and it's hard to know what the Portland ratio is in relation to "Fly Ash" ratio. I have heard in my Mapei training classes that this is generating huge problems on commercial projects and Mapei has recommended to me that I inquire on the cement type and mix ratio for any commercial project.

    I'm not sure if companies like Laticrete, Custom, Mapei or the like use any "Fly Ash" in their production or if they even know it's included perhaps with a portland cement order.
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