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 09-02-2008, 08:49 AM   #1
noaloha
Registered User
 
noaloha's Avatar
 
Join Date: Sep 2008
Location: Boston, MA
Posts: 22
Derek's Master Bathroom Remodel

Hello everyone,

I've been poking around in this forum for a while now. So much good information. I was able to answer most of my questions while sifting through the forums and the Liberry. Only a few questions remain at this point. But first, some details about our project: we're converting a room off the master bedroom into a master bathroom. We're installing a custom corner shower approximately 36"x38". All of the plumbing is in and I'm preparing to build the shower base. The plumber (in fact every plumber I got a quote from) wanted to use a copper pan (we're in MA). Unfortunately it wasn't until after the pan was purchased that I discovered what a mistake it was. So although I own the copper pan it hasn't bee installed yet and I've opted to do it right and use Noble products to build the pan. I'm planning on using Noble Pro-Slope, Chloroloy liner (with dams for the outside corner and curb/wall corners), and a Noble clamping-drain. We're going to tile the shower walls with tumbled carrara marble (6" for the walls and 1" for the floor).

We'll be tiling the bathroom floor with the same marble (12") over electric radiant-heat cable. We've pulled up everything except the original subfloor boards to install the plumbing. I was planning on putting 3/4" plywood on top of that followed by the radiant-heat cable encased in SLU. Then I read that cement backerboard can also be used as a substrate. I'd prefer to use that if possible because it's easier to work with and it won't warp if it gets wet.

My questions:

1) I'm not sure which value to use for the joist material for the Deflectolator. Given the age of the joists (150 yrs) should I assume they're "cracky"? I ask because choosing "cracky" over "good condition" crosses the threshold to thumbs down for natural stone. If I should assume they're "cracky", then what are my options for beefing up the floor enough to safely use marble? Would we gain strength by pulling up the original boards and putting down 3/4 plywood followed by cement board (or two layers of cement board)?

2) The floor in the bathroom slopes towards one side of the room (the house is 150 years old). How should I level the area under the shower pan? Should I:
  1. build up the floor first, install the cable, and level the entire floor with SLU, then install the shower drain and pan
  2. build up the floor and only level under the shower first (with thinset perhaps or some other material), then install the shower drain and pan, etc. before installing the radiant heat cable and covering it SLU

Thank you,
Derek
noaloha is offline   Reply With Quote
Sponsored Links
Unread 09-02-2008, 09:00 AM   #2
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 92,660
Welcome, Derek.

1. You can determine the type and condition of the floor joists by lookin' under there. 150 year-old joists might be in just fine condition, or they could be candidates for immediated replacement.

Having a joist structure that meets the necessary L/720 requirement for natural stone would be rather unusual unless the floor was designed for a natural stone installation. Do tell just what you have under there.

2. For a natural stone installation you must have a double-layer subfloor of plywood or OSB, regardless the joist spacing. If your sawn board floor is in good condition, it may serve as your first layer, but if it's all cut up from the plumbing changes I'd consider starting over at the joists with new plywood. Then a second layer of plywood (can be thinner) and then your CBU or membrane. There is never a good time to use more than one layer of CBU.

Removing all the subflooring would give you a good opportunity to level/flatten the tops of the joists by sistering as necessary.

If your floor is not level under the shower I would simply abandon the use of the Noble pre-slope and make the necessary pre-slope of deck mud to fit your floor and shower size situation. Pretty easy to do.

What is your plan for the walls of the shower?

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 09-03-2008, 08:49 AM   #3
noaloha
Registered User
 
noaloha's Avatar
 
Join Date: Sep 2008
Location: Boston, MA
Posts: 22
CX, thanks for the quick response! I took a look at the joists and they look fine to me. I don't see any cracks, knots, or splits. They appear to be straight and very sturdy. I plugged the numbers into the Deflectolator and it says:
Quote:
Thank you for using the John Bridge Forums Deflect-O-Lator :-)
For joists that are Unknown wood, but in good condition, 7 inches tall, 2 inches wide, 16 inches on center, and 7 feet long between supports, the deflection calculated is 0.081 inches.
This translates to a deflection of L / 1040.
Since the maximum deflection for tile is L / 360, and for natural stone is L / 720, your floor is rated for Ceramic tile or Natural stone, Congratulations!
So I need two layers of subflooring...using the recommendations described by Woeste and Nielsen, I presume? What thickness would you recommend for the first layer? Should both layers' grain go perpendicular to the joists or just the first one? Then I should cover that with 1/4" CBU or Ditra? Is one preferable to the other if I'm going to put down radiant-heat cable and SLU, or would the SLU serve the same purpose as either of those?

As for leveling under the shower, how should I level the shower curb? I need it to be exactly perpendicular to the wall because we're planning on installing custom glass for two of the shower walls. My first thought was to shim the curb, put mud down to level the shower pan, then any space under the curb would get filled in by the SLU when I cover the cable. Do you see any issues with that approach?

With regards to the shower walls, I've squared up the shower corner and made adjustments so that all of the studs are plumb. I'm planning on using 15# roofing felt for a vapor barrier followed by a 1/2" CBU.
noaloha is offline   Reply With Quote
Unread 09-03-2008, 08:59 AM   #4
bbcamp
Registered User
 
Join Date: Jul 2002
Posts: 30,274
Quote:
So I need two layers of subflooring...using the recommendations described by Woeste and Nielsen, I presume?
Yes
Quote:
What thickness would you recommend for the first layer?
3/4"
Quote:
Should both layers' grain go perpendicular to the joists or just the first one?
Both
Quote:
Then I should cover that with 1/4" CBU or Ditra? Is one preferable to the other if I'm going to put down radiant-heat cable and SLU, or would the SLU serve the same purpose as either of those?
Either CBU or Ditra will work. I'd use Ditra because it's lighter. Use SLC (Self Leveling Concrete) to bury the heat mat. Follow their instructions carefully. Install the Ditra on top of the SLC.


Quote:
As for leveling under the shower, how should I level the shower curb? I need it to be exactly perpendicular to the wall because we're planning on installing custom glass for two of the shower walls. My first thought was to shim the curb, put mud down to level the shower pan, then any space under the curb would get filled in by the SLU when I cover the cable. Do you see any issues with that approach?
Like, CX, I think that if your floor is un-level, build your own curb and preslope. You want these items to be fully supported by the subfloor, and they're too cheap to make that buying them takes away money for more important things, like towel racks and adult beverages.

Quote:
With regards to the shower walls, I've squared up the shower corner and made adjustments so that all of the studs are plumb. I'm planning on using 15# roofing felt for a vapor barrier followed by a 1/2" CBU.
Good!
bbcamp is offline   Reply With Quote
Unread 09-08-2008, 05:34 AM   #5
noaloha
Registered User
 
noaloha's Avatar
 
Join Date: Sep 2008
Location: Boston, MA
Posts: 22
Quote:
Like, CX, I think that if your floor is un-level, build your own curb and preslope. You want these items to be fully supported by the subfloor, and they're too cheap to make that buying them takes away money for more important things, like towel racks and adult beverages.
bbcamp, just to confirm, it sounds you're saying I should install my base curb structure (3 stacked 2x4s) as the floor is, then when I cover it with mud I can account for any difference in levelness?
noaloha is offline   Reply With Quote
Unread 09-08-2008, 11:27 AM   #6
bbcamp
Registered User
 
Join Date: Jul 2002
Posts: 30,274
Yes, you can do it that way, or you can shim the 2x4s. Since the curb will likely be stood on, the shims should be more or less continuous.
bbcamp is offline   Reply With Quote
Unread 09-10-2008, 07:17 PM   #7
noaloha
Registered User
 
noaloha's Avatar
 
Join Date: Sep 2008
Location: Boston, MA
Posts: 22
Thanks for all of the feedback. Just when I think I'm finished asking questions I come up with more Anyway, here goes:

With regards to my existing subfloor, it appears that removing it is going to be rather difficult because the studs in the adjacent wall sit on top of the subfloor and the boards actually go under the wall and into the next room (balloon construction). So in the interest of not doing more than I have to: given the span and spacing of the joists does this look like an acceptable substrate that can I put 1/2" plywood over, followed by SLC and ditra? The boards are 3/4" thick. Or would that be a recipe for disaster? Here are some pics:

Subfloor under the toilet
Subfloor under the shower
Studs on top of the subfloor

Also, while at Lowes the other day I saw a PVC clamping ring drain with the shape and finish I wanted. Originally I had planned on buying one from Noble, but they didn't have the style I wanted (chrome with a square strainer). The one at Lowes is also 1/3 the cost, but does that mean it's 1/3 the quality? Would I be safe using this over a Noble drain?
noaloha is offline   Reply With Quote
Unread 09-10-2008, 07:38 PM   #8
Mike2
Registered User
 
Join Date: Nov 2003
Location: LaConner, Washington
Posts: 13,694
If that square chrome drain you found at Lowes is made by Oatey, then I think you'll find the quality quite satisfactory. Oatey makes good drains.

For that plywood layer over your existing board sub-floor, 1/2" ply would be fine for ceramic tile. However, since you are using marble, your deflection requirements are more demanding. I'll recommend you bump that up to 3/4" ply.
Mike2 is offline   Reply With Quote
Unread 09-11-2008, 07:13 PM   #9
noaloha
Registered User
 
noaloha's Avatar
 
Join Date: Sep 2008
Location: Boston, MA
Posts: 22
Thanks Mike. Anyone else have thoughts about the integrity of the subfloor?

I normally prefer to use screws instead of nails even though they take longer to install. I like the fact that 1) they seem stronger and less likely to work loose and 2) they're easier to remove if/when the time comes to renovate. What type and length of screws would you recommend to install the 3/4" plywood underlayment?
noaloha is offline   Reply With Quote
Unread 09-11-2008, 07:42 PM   #10
tilelayer
South East PA Tile Contractor
 
tilelayer's Avatar
 
Join Date: Aug 2004
Location: Delaware County, PA
Posts: 6,584
I would use 2" exterior deck screws they are like green or tan at hd and come with a free blue bit



Ps you spell your name wrong!!
__________________
-Derrick

***New Here?? Click here to add your name to your signature***

Check out my Blog and see my latest tiling projects!



Specializing in Kerdi Showers
tilelayer is offline   Reply With Quote
Unread 09-11-2008, 08:10 PM   #11
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 92,660
Derek, would you please go to the UserCP, find Edit Signature and enter your first name there so it appears in each post for us to see? Yeah, yeah, I know it's in the title, but I ain't lookin' at the title when trying to respond, I'm lookin' at your last post, eh?

And I don't even care if you spell it wrong.

I agree with Mike that 3/4" ply would be best over that subflooring you have there for a natural stone installation. And I'd want you to pre-drill all the screw holes in the plywood or you'll not likely get a good fastening and will likely suffer much screw-jacking. Be sure the long joints in the plywood fall near the center of one of them boards so's to be well supported, eh?

The commonly available 1 5/8ths-inch decking screws would be my fastener of choice. Derrick's two-inch wouldn't be too excessive, but he spells his name funny, eh?

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 09-15-2008, 04:09 PM   #12
noaloha
Registered User
 
noaloha's Avatar
 
Join Date: Sep 2008
Location: Boston, MA
Posts: 22
So I passed my rough building inspection today (woo-hoo!) which means I can finally start installing the flooring and the shower pan. I went to a lumber store, told 'em what I needed, and they loaded two sheets of 3/4" plywood onto my car. Then as I got home and started unloading it I noticed that it says "CD" and "sheathing" on it. I think they gave me the wrong stuff. Can I use this for my underlayment or do I need to get something better?
__________________
Derek
noaloha is offline   Reply With Quote
Unread 09-15-2008, 04:32 PM   #13
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 92,660
Great PITA that it is, Derek, you really need to take that stuff back and exchange for some BC or AC or similar Exterior Glue Plywood.

The CD stuff has not only large voids in at least one face, but similar voids within. Not suitable to your needs here.

Congratulations on your green tag.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 09-16-2008, 08:43 AM   #14
noaloha
Registered User
 
noaloha's Avatar
 
Join Date: Sep 2008
Location: Boston, MA
Posts: 22
I called them this morning and told them what I needed. They delivered two new sheets of sheets and took the other stuff back...for free. The stamp on the new stuff says:
Quote:
Underlayment
Exposure 1
PS 1-07
I believe this is the good stuff. It's not marked 'BC' but from what I can tell it's implied in the PS 1-07 standard (correct me if I'm wrong).
__________________
Derek
noaloha is offline   Reply With Quote
Unread 09-16-2008, 09:13 AM   #15
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 92,660
Well, the PS 1-07 tells us something, but I think it's still gotta have a grade stamp on there somewhere.

I think the PS 1 is mostly a specie grouping and doesn't mean much to us except that the 1 means it's a suitable group. Our friend Mikey (Mike2) keeps up with that sorta thing much better than do I and may know more about it.

But I do believe there's still gotta be a grade stamp with As or Bs or Cs or whatever to go with that PS stamp.

If not, ain't the first time I been wrong. Not even the first time this week.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   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


All times are GMT -6. The time now is 04:48 PM.


Sponsors

Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Copyright 2018 John Bridge & Associates, LLC