Ceramic Tile Advice Forums - John Bridge Ceramic Tile

Welcome to John Bridge / Tile Your World, the friendliest DIY Forum on the Internet


Advertiser Directory
JohnBridge.com Home
Buy John Bridge's Books

Go Back   Ceramic Tile Advice Forums - John Bridge Ceramic Tile > Tile & Stone Forums > Tile Forum/Advice Board

Sponsors


Reply
Thread Tools Search this Thread
Unread 12-27-2019, 10:24 PM   #1
JohnpaulTH
Registered User
 
Join Date: May 2019
Location: Prineville, OR
Posts: 42
Johnpaul's mud shower saga

Hi All,

Last time I posted I was asking for advice on a non-industry standard install.
Now I am asking for advice on an industry standard. (Maybe I finally learned my lesson., thanks to Sal DiBlasi and Isaac Ostrom, and all the folks here on the forum...)
I have installed all the floors in the bathrooms and laundry-room/mudroom and am in the process of preparing our tub surround for tile.
I was going to use the hardiebacker that was already installed, but realized that the walls were out of square, plumb, and level in ways I didn't even realize were possible.
So my dad mentioned that he had seen some tilers use this particular process to straighten the walls. I researched it and found the one coat float.

So I have all the plywood backing installed and the aquabar, and then I get the TCNA Handbook for Christmas!
Well I looked it up and thought I found it in section W222-19. but then realized that it was probably B440-19.

So I had several questions:
  • I have not been able to find self furring lath or furring nails. should I use furring strips? is furring even required? When I look up furring nails, I find a lot of stucco contractors who say that for stucco there needs to be a quarter inch gap behind the lath, and that furring strips are a bad idea.
  • Does all the advice about stucco apply to floating walls?
  • The weather is pretty cold over here in central oregon. (37 - 40 degrees fahrenheit)
    Do you have any advice for mixing the mortar in cold weather?
    I am planning to use a mixture of 5 parts sand, 1 part portland cement, and 1 part lime.
    Should that mixture be adjusted for the cold weather?
  • The TCNA handbook does not appear to list plywood as a valid backing in B440-19
    However the aquabar tub install guide does. Do I follow the install guide or the handbook?
  • The local tile supply shop told me that all their contractors use hardiebacker.
    Is it crazy to float the walls?

Can you understand what I am asking?
Should I create multiple threads?

Thanks in advance,
Johnpaul
__________________
Johnpaul
JohnpaulTH is offline   Reply With Quote
Sponsored Links
Unread 12-28-2019, 12:11 AM   #2
Tool Guy - Kg
Moderator -- Wisconsin Kitchen & Bath Remodeler
 
Tool Guy - Kg's Avatar
 
Join Date: Feb 2005
Location: Oak Creek, WI
Posts: 21,652
Keep this single thread and hang tight. A mud guru who has done this hundreds of times will be by to get you your answers.

__________________
Tonto Goldstein... but my friends call me Bubba

Help an awesome summer camp!
Tool Guy - Kg is offline   Reply With Quote
Unread 12-28-2019, 12:33 AM   #3
Davy
Moderator -- Mud Man
 
Davy's Avatar
 
Join Date: Jan 2003
Location: Princeton,Tx.- Dallas area
Posts: 32,219
I want to meet this mud guru, maybe he needs a job.

I've never used furring lath so I can't say. Maybe someone else has.

I think so but maybe there's stucco advice I don't know about. You may have to explain what you're talking about.

I've always mixed my mud the same regardless of the temperature. Even if it's cold outside, I've always had heat inside the house. If the house heat wasn't on, I'd bring my own heater.

My mud is usually 4 to 1 to 1.

Other than studs, I've never liked any type of wood behind my mud walls.

I mud all my showers, it's the best substrate in my opinion. Having flat, plumb and square walls doesn't sound crazy to me.
__________________
Davy

www.davystephenstile.com
Davy is offline   Reply With Quote
Unread 12-28-2019, 12:53 AM   #4
Tool Guy - Kg
Moderator -- Wisconsin Kitchen & Bath Remodeler
 
Tool Guy - Kg's Avatar
 
Join Date: Feb 2005
Location: Oak Creek, WI
Posts: 21,652
Quote:
Originally Posted by Davy
I want to meet this mud guru, maybe he needs a job.
Cripes! I was talking about you! Although, I should have changed the “hundreds” to “thousands” to be more accurate.
__________________
Tonto Goldstein... but my friends call me Bubba

Help an awesome summer camp!
Tool Guy - Kg is offline   Reply With Quote
Unread 12-28-2019, 09:56 AM   #5
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 89,531
Welcome back, Johnpaul.

1. Properly executed stucco is always a three-step process; Scratch coat, Brown coat, and Finish coat and each coat is of a different materials mix. And the lath, or stucco mesh, is always required to be furred away from the backing material. It is not the same as doing wall mud for ceramic tile installations.

2. See #1.

3. See Davy's post #3.

4. You'll note in Method W222 in your new Christmas present the Environmental Exposuer Classifications section includes only Res1 when used with wood backing and B440 makes no provision at all for wood backing material. There's a reason for that; wood is not a suitable backing for your one-coat mud and tile in a wet application. (Open the Christmas book to page 44 for more on environmental classification according to the ceramic tile industry.)

In exterior stucco applications, there is almost always (I know of no exception, but I suppose it's possible) a requirement for a double moisture barrier behind the furred stucco mesh or lath. And that environment sees far, far less moisture than will your shower walls.

If you prefer the Aquabar instructions to the TCNA recommendations, that's up to you. I would not use plywood behind my one-coat mud shower walls. I would not balk at all at the use of drywall, but I'd refuse plywood.

5. Not at all crazy and in your application I would have left the Hardiebacker walls in place, installed a cleavage membrane and metal lath over the Hardiebacker and done the one-coat mud over that. Difficult to attach the lath with the traditional hammer tacker, but I have a pneumatic stapler that would make short work of it.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!

Last edited by cx; 12-28-2019 at 02:39 PM. Reason: typo
cx is offline   Reply With Quote
Unread 12-28-2019, 10:34 AM   #6
JohnpaulTH
Registered User
 
Join Date: May 2019
Location: Prineville, OR
Posts: 42
Thanks for all your replies so far,
special thanks to CX for pointing out "Res1"
If I understand correctly:
  • Just because something applies to Stucco does not mean it applies to Mud walls
  • Furring lath is not necessary
  • Plywood is a bad idea in this application due to moisture considerations.
  • Cold weather is not a worry since we have heat inside.
I was aware of the 4:1:1 mix, and have heard that some go all the way to 7:1:1 or half the lime. (I also saw someone do a 3:1 scratch coat without any lime)
will 5:1:1 still work? Does anyone out here do that? Is their a definitive "Good" ratio, or is it a matter of personal preference?

B440 specifies a cleavage membrane, but calls the waterproof membrane optional.
Aquabar "B" says it is a moisture barrier, which as I understand is not the same as a waterproof membrane. Is that insufficient protection?
Their warranty is very generous saying that (if I read it correctly) they will cover the cost of defective material, but nothing else. Very confidence-inspiring.
If I do end up taking the plywood out, I was thinking of doing B411 instead, and skip putting up backer. If I do that, is the scratch coat a different material? I would research that method of course.

Thanks again!
__________________
Johnpaul
JohnpaulTH is offline   Reply With Quote
Unread 12-28-2019, 01:20 PM   #7
JohnpaulTH
Registered User
 
Join Date: May 2019
Location: Prineville, OR
Posts: 42
Quick update -
We have decided to follow the aquabar tub install guide [PDF] which states
"Aquabar "B" ceavage membrane is required if a solid backer of water resistant gypsum or plywood rated exposure 1 or exterior is used."
I noticed that the TCNA handbook states that furring strips should be used if the lath cannot be directly attached to the studs. can I install it through the plywood to the studs?
__________________
Johnpaul
JohnpaulTH is offline   Reply With Quote
Unread 12-28-2019, 03:17 PM   #8
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 89,531
If you research the acceptable cleavage membranes you'll find that each is also a moisture barrier and it is acceptable to use only that moisture barrier for your tub/shower walls over an acceptable backer material. Acres and acres of mud shower walls have been quite successfully constructed in that manner over many decades. The very best moisture barrier material to use in that application is roofing felt, in my opinion. Exterior wall packages must be properly constructed for anything to work at it's full potential, though.

It was (may still be) even common to do one-coat mud shower walls with no moisture barrier behind the mud at all and no waterproofing membrane on the inside of the walls. It's not a good idea, but having experimentally tested fat mud for absorption and wicking, I can see how many of those showers survived a long and happy life. Still not something I'd recommend.

If you elect to do the scratch-and-brown mud over metal lath over open wall cavities, you still need the moisture barrier behind the lath unless you plan to use a waterproofing membrane on the interior of the shower. The two-coat mud is as good as it gets in shower construction, but it does require a bit of a learning curve, perhaps a little steeper than the one-coat method. But you could hang your NTCA Handbook on that perfectly plumb, square, and flat wall and call yourownself "Master Mud Guy."

And in a DIY application where labor is free and mud nearly so, you could cover the interior of your mud with a sheet type waterproofing membrane and still be within your original shower construction budget. Presuming your original budget was reasonable, of course.

[Edit] Now that I see your post #7:

What application are you looking at for the use of the furring strips?

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!

Last edited by cx; 12-28-2019 at 03:30 PM.
cx is offline   Reply With Quote
Unread 12-28-2019, 03:35 PM   #9
JohnpaulTH
Registered User
 
Join Date: May 2019
Location: Prineville, OR
Posts: 42
I had heard (more stucco propaganda) that the lath had to stick out from the wall 1/4" I did not see any such recommendation in the TCNA handbook, but I did see the thing about the studs, mentioned above.
I have access to the studs behind the plywood, so I am assuming that I do not have to worry about the furring strips.
Does the lath have to be installed away from the wall?
__________________
Johnpaul
JohnpaulTH is offline   Reply With Quote
Unread 12-28-2019, 03:39 PM   #10
JohnpaulTH
Registered User
 
Join Date: May 2019
Location: Prineville, OR
Posts: 42
One other thing,
My parents have not yet decided what format of tile to go with, but they found some 4" or 6" at the tile supply store that caught their eye.
Does the format affect the float design?
__________________
Johnpaul
JohnpaulTH is offline   Reply With Quote
Unread 12-28-2019, 05:43 PM   #11
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 89,531
The metal lath is attached firmly to the face of the backing material if a backing material is used.

A mortar bed doesn't care a whit what size tiles are attached to it.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is offline   Reply With Quote
Unread 12-28-2019, 06:33 PM   #12
JohnpaulTH
Registered User
 
Join Date: May 2019
Location: Prineville, OR
Posts: 42
Thanks!
__________________
Johnpaul
JohnpaulTH is offline   Reply With Quote
Unread 12-28-2019, 07:49 PM   #13
Davy
Moderator -- Mud Man
 
Davy's Avatar
 
Join Date: Jan 2003
Location: Princeton,Tx.- Dallas area
Posts: 32,219
The self furring lath I've seen has dimples bent into the backside that holds the lath away from the wall. We usually try to keep our single coat jobs 1/2 inch thick and the dimples would make it hard to do that in some places. But even when using flat lath, the mud will surround the lath if it pressed in well so we've never used the self furring lath.

The 4 to 1 to 1 mix is kind of a starting point for me. Seems like each brand of Portland acts different from the other and I may have to fine tune the mix. Experience is the best teacher and when mixing a batch I can tell if it needs more or less cement or lime. When I buy cement and lime, I try to stick with the same brands from job to job. The sand changes too from pit to pit.
__________________
Davy

www.davystephenstile.com
Davy is offline   Reply With Quote
Unread 12-28-2019, 08:15 PM   #14
JohnpaulTH
Registered User
 
Join Date: May 2019
Location: Prineville, OR
Posts: 42
Thanks!
I am using this lath (yes it's from lowes.)
__________________
Johnpaul
JohnpaulTH is offline   Reply With Quote
Unread 12-28-2019, 09:16 PM   #15
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 89,531
Ceramic tile industry requires the metal lath be at least 2.5 pounds per square yard, Johnpaul. I can't find any reference to the weight of that "stucco netting," but I'd suspect it may well be only 1.75 pound material. You might wanna check on that.

Our local Home Depots generally carry the 2.5 pound stuff.

Safety tip: If you go to the store to look at the stuff, wear gloves. If you actually wanna use the stuff, wear heavy gloves.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is offline   Reply With Quote
Reply

Stonetooling.com   Tile-Assn.com   National Gypsum Permabase


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
A Sad Bathroom Saga AmiT Tile Forum/Advice Board 17 12-13-2011 11:25 AM
Mikes Shower Saga MikeyL Tile Forum/Advice Board 46 02-19-2008 07:20 PM
Master Bathroom Shower Saga we_bought_a_hammer Tile Forum/Advice Board 14 09-30-2006 04:45 PM
Shower Saga: pan test failure and PVC-ABS gluing? RichTile Tile Forum/Advice Board 6 11-21-2004 07:21 PM
Shower Saga: The beginning (shower door width?) RichTile Tile Forum/Advice Board 7 08-06-2004 02:12 PM


All times are GMT -6. The time now is 01:52 AM.


Sponsors

Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Copyright 2018 John Bridge & Associates, LLC