A few quick questions - tub install

[jimmyt]

Can someone please "check my math" to make sure I am on the right path.. I am about to install a kohler archer soaker tub and want to make sure before I commit that I have my act together.

First question - I am planning on adding ledger boards to the back and side walls to give the tub a place to rest - no support - that comes from the floor. Is the ledger needed on the left / right side or just the long side? (The one that is in the picture was for the original builders grade steel tub.)

Second - I am planning on adding a 2" +/- mortar bed underneath to firm up the base. Is one better than the other? - Either Quickcrete Mortar 1102 or Quickcrete 1103 - Sand/Topping Mix? My plan is to put a plastic sheet / vapor barrier on the subfloor and then pile in the mortar and set the tub? Yes, No?

Third and final for now - I am planning on adding blocking to the walls to support the wonderboard and then kerdi on top of it, lipping it over the tiling flange for the vapor barrier. the existing vapor barrier will be removed. Since that is an external wall, what about the area below the ledger board - would it need a standard vapor barrier or does the tub cover it. My guess is it needs it since there will be space between the tub and exterior insulation.

thanks!

 

[Jadnashua]

A sand topping mix (aka deckmud) is probably better. You will have nearly zero success of getting things level if you try to spread the stuff out...place a bunch of piles, then smush the tub down carefully (if you ledger boards are level and at the height you want, stop there, but double check the level). Deck mud does not flow, it's like wet beach sand. Mix only with enough water to hold together if you grab a handful and squeeze it together. It should not drip...excess water leads to shrinking.

You'll want to pick up a tube of KerdiFix to make the seal between the Kerdi and the tub. Permanent, waterproof, and compatible with the Kerdi. There's a video on Schluter's channel that shows exactly how to do this.

 

[Sponsor]

 

[jimmyt]

Jim - thanks! Planning on installing it this weekend. Any thoughts on what to do below the ledger? add vapor barrier or pack it with installation? am leaning towards vapor barrier.

 

[Jadnashua]

Local building codes may have a say in this...if it is an outside wall, then probably yes...inside, since it is (supposed to be!) dry, probably doesn't matter. Put some plastic or tar paper on the floor before the piles of mortar so the moisture isn't wicked out of it. Some like a layer on top as well so it's easier next time to pull the tub out. You're looking for support, not adhesion.

 

[JohnfrWhipple]

This work so far looks pretty Mickey Mouse.

• Looks like you bought cheap plastic.
• The plastic appears to be from a square container. No 6mil markings on it.
• Your missing aquastical sealant.
• Missing Tuck Tape.
• Insulation should extent to the floor.
• No niches on outside walls.
• Vent line hole is drilled to tight.
• Missing silicone on sub floor sheathing.

But ya - Kerdi Fix will solve all your problems! lol kidding. You do know Jim does not build showers for a living. In regards to local code. It trumps all the info your product manufactures print.
The ledger board gets installed over the vapour barrier not under it.

Good luck.

 

[jimmyt]

Thanks.. I guess A few comments.. What you see there is the tear out after I was done removing things. The plastic was there - appears to be 6 mill. Not sure what aquastical sealant is. There is sealant between the wall and subfloor as well as wall and top plates for the trusses. Tuck tape is on the outside of the house. Unfortunately this house was built with t-ply - not much I can do about that. Insulation did and will extend to the floor - it was just removed. The vapor barrier is now under the ledger which was relocated higher to accommodate the new tub. Those are not niches, they were blocking that was in the original frame up of the house. I since have extended the blocking to accommodate the wonderboard. The kerdifix is to bond the kerdi to the tub to create the vapor barrier for the the wall so I don't make a mold sandwich. Not sure what you mean by vent hole is drilled too tight - there is about 1/2" play around the vent pipe as it comes up thru the floor. What does missing silicone on subfloor sheathing mean? There is sealant under the bottom plates of all walls.

I hope to set the tub this weekend. My soldering skills are rusty, so its been a bitch soldering the brass tub mixing valve to the copper. The copper to copper drop and bend for the tub spout was easy.. not the rest.. maybe I need to go to a mapp torch instead of propane

thanks

Jim

roblems! lol kidding. Yo

 

[JohnfrWhipple]

So you buy in to the vapour barrier discussions.

The biggest problem you have now is too much bad info in your head.

Please before asking any more questions ask your local inspector about vapour sandwich. Then call the TCNA or TTMAC and ask anyone what the official rule is on this. What I see online is a bunch of old men spreading the same bull shit from here to Sunday. Most don't know their ass from a hole in the ground. There is no vapour barrier info at all. It has not been studied. It is not scheduled to be studied anytime soon.

But hey - good luck with Kerdi Band at 4/1000" being a vapour barrier for you. While you ponder that why not call Schluter and ask them if it can be used in a high use steam shower. Their answer should make you think.

Maybe Jim can help you. He has been to lots of workshops and never worked in this business. My answers come from real builds with real inspectors and real permits. But what do I know.

Before entertaining the idea of skipping a vapour barrier and following a Schluter approach try getting IN WRITING an email that states this is acceptable. If you do please share it with us - know one ever has. If you don't ask yourself why you can not get it. If your told by someone ask yourself why the warranty on Schluter says no verbal instructions are allowed and only the printed ones can be. Have you seen in the Kerdi workbook where it says kerdi band and kerdi are replacements for a proper vapour barrier.

If you can tell this is a touchy subject for me.

The top tec from Schluter is a man named Dale Kempster. He is part of both the TCNA and TTMAC I think. Here is his email.

Ask him to tell you it's OK.

Dale Kempster <DKempster@schluter.com>

All you need to do - or anyone really is email this man and ask. When someone post a reply back I'll eat crow. But like I have said before on countless discussions there is no vapour barrier sandwich study. Never has been and most likely never will be.

 

[jimmyt]

There is too much in my head .. that's for sure.. I see that you dont like shluter and thats ok - funny thing was I had a call into the local code official / inspector and ironically he called me back this morning.. lol.. First off, they both like the schluter and laticrete products. Their recommendation on the mold sandwich was much like yours - there is no definitive answer and they even talked about how even the manufacturers are quiet on the issue. From a code perspective, here locally, exterior walls require a Perm rating of 1 or less to be considered a vapor barrier, so from their perspective, they would accept kerdi or hydroban membrane as meeting the spec - when I asked what he would do - he simply said 6mill poly, backer, kerdi.

thanks for your insight!

 

[JohnfrWhipple]

.....From a code perspective, here locally, exterior walls require a Perm rating of 1 or less to be considered a vapor barrier, so from their perspective, they would accept kerdi or hydroban membrane as meeting the spec - when I asked what he would do - he simply said 6mill poly, backer, kerdi.

thanks for your insight!

Thanks for calling. Now you know like I and every other person that actually checks with city hall.

Next lesson.

See what the inspector listed. backer. That could be anything. Use cement board. Keep the Kerdi away from the top of the shower. Short by 6"-8".....

Ever wondered why there is a requirement to keep back fill away from your foundation walls top 8"? Ever wonder why you need to keep 8" of exposed concrete showing? When you understand why this is a requirement you will understand why I like to waterproof my builds the way I do.

Why not use Noble Company's ValueSeal, WallSeal, NobleSeal TS in replacement of Kerdi. Or Ardex 8+9 in replacement of Kerdi. Or the sheet membrane from laticrete or Custom. Any of these choices will not limit your selection of setting materials so much. Kerdi would be the last thing I would recommend for a clients shower.

Last time I saw it installed in a shower it was installed wrong so I ripped it out.

 

[Jadnashua]

John has a big chip on his shoulder about Schluter products...they disagree about how it works and how it should be installed...JOhn's been in the business a lot shorter time that Schluter has been selling and warrantying their products, and has lots more smart people working on it to ensure it does what it should do. Enough said on that.

John likes to throw out little quips...like how thin the material is. It's waterproof, it works, just like 1/8" window glass is waterproof as is 1/2" plate glass...used in different circumstances, you use what you need. You're not building a steam shower, and Kerdi meets all of the code requirements for a shower. Now, if you were building a commercial steam shower, that's a different story and they have a product that works in that situation. To make a reliable seam with the stuff, you either butt the main sheets then put the banding material over it, or overlap the sheets...in both cases, you have the full thickness of the material PLUS the Kerdiband, when you use that. It's mostly irrelevant how thick it is. Thick, like the membrane he likes to use is 30mils, or over 3x (nearly 4x) thicker...see how thick your seams are if you use that one!

Some CBU manufacturers want you to use caulk between the ply sheets seams, most don't, and the industry doesn't list it as either being required or recommended, nor do most of the thinset manufacturers. John thinks it's required...you can go with his recommendation, or not as you see fit, just like anything else you read here. You pulled his chain when you mentioned you used Kerdi, so take that with a grain of salt!

 

[JohnfrWhipple]

Wow - Jim knows a lot about everything. Me included.

Lets go back to the first post. Part three of that post. In the big picture this fellow has not blindly followed lame online knowledge and built a shower that does not meet local code.

Why anyone wants to use a shower waterproofing membrane that is just thick enough. Just OK - is beyond me. Why anyone would build a shower and use unmodified thin-set boggles my mind. When ever other product out there is easier to use.

But like our Kerdi salesman likes to preach "If you do everything perfect you'll be OK"

Good luck with the shower build. Remember Jim did not warn you about local code - what else we he forget to tell you. Remember he does not nor ever has worked in this industry.

 

[Jadnashua]

John, just showing his love. If John reads and understands the industry guidelines and the manufacturer's instructions, he might not spend as much of his customer's money and still get a reliable job. Overkill is fine if you want to pay for it, but there's a lot already built into the products. Poor workmanship with ANY product is no excuse, and can lead to failures. John likes redundancies because he often doesn't follow the manufacturer's instructions, or doesn't trust that they have a clue, even if they've been doing it decades longer than John has had his shingle out. Just read some of his earliest posts (if he hasn't deleted them, making the thread useless, or very hard to follow), and you can follow his learning curve. Schluter has been making and selling their Kerdi membrane for decades. If it didn't work, they'd be out of business, not constantly growing. If it didn't, in the past few years, Custom Building Products, Laticrete, Mapei, and USG wouldn't have come out with similar products (Schluter's patent ran out). Passes all of the industry tests and certifications required to build a shower. Maybe they know something that John doesn't, they certainly have more engineers to work out the details. John doesn't follow the North American installation instructions and manufacturer's installation instructions. He has a big chip on his shoulder. He likes Noble products, a good company, solid products, just not for everyone or every job. So, don't feel belittled by choosing the products you did...they work, have a solid company backing you up and work fine, if you install them per their instructions. John just likes to foist that onto people since he publically decided to stop using Schluter products (course, since that declaration, he has more than one post where he has used them). Certainly not for every job, or every situation, but it works, as do the others out there.

 

[JohnfrWhipple]

.....Third and final for now - I am planning on adding blocking to the walls to support the wonderboard and then kerdi on top of it, lipping it over the tiling flange for the vapor barrier. the existing vapor barrier will be removed. .....

AHHH Wrong.

Horrible Plan.

We set this fellow straight.