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 09-03-2020, 07:55 PM   #76
arnav
Registered User
 
Join Date: Aug 2014
Location: FL
Posts: 319
what it looks like with half the underlayment out...

I took out half the underlayment where there was rot. This is what 18 years of busy termites looks like. Its interesting they would rather eat cheap ply than the dimensional lumber in the attic. Perhaps since the lumber in the attic is periodically treated. why why why is using wood in Florida is allowed. Could they have used PT ply? Would it hurt to spray boric acid? When I fix this I'll sprinkle timbor between the two layers. I'll spray the wood as well (I'll need to give it enough time to dry) - unless you can use PT (i know for furring strips you recommended against it)?
Also attached the underlayment stamp.
Attached Images
   
__________________
Dan
Much like this project, my posts are still under construction

Last edited by arnav; 09-03-2020 at 08:11 PM.
arnav is offline   Reply With Quote
Unread 09-03-2020, 08:03 PM   #77
arnav
Registered User
 
Join Date: Aug 2014
Location: FL
Posts: 319
Despite all that the subfloor seem to look ok. It is definitely structurally sound. I have seen badly eaten wood that crumbles to the touch and that is not it.
Attached Images
   
__________________
Dan
Much like this project, my posts are still under construction
arnav is offline   Reply With Quote
Unread 09-03-2020, 08:08 PM   #78
arnav
Registered User
 
Join Date: Aug 2014
Location: FL
Posts: 319
Joists

This how the joists are running. The right most joist ends where the wall start.
What do you think is the best course of action? New underlayment or replace the subfloor as well?
Thanks for the help
Attached Images
 
__________________
Dan
Much like this project, my posts are still under construction
arnav is offline   Reply With Quote
Unread 09-03-2020, 08:24 PM   #79
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 90,953
That's 24" on center joist spacing, Dan?
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 09-03-2020, 08:52 PM   #80
arnav
Registered User
 
Join Date: Aug 2014
Location: FL
Posts: 319
Aspirationally. Right and middle joists are 24.5 O.C.
Middle and left joists are 25.5 O.C.

Assuming I quickly did the math correctly. Originally I measured not O.C. which was 21" between right and middle joist and 46.5" between left most joist and right most joist.
__________________
Dan
Much like this project, my posts are still under construction
arnav is offline   Reply With Quote
Unread 09-03-2020, 08:56 PM   #81
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 90,953
Better they should have aspired to be only 16" on center, but.......

I would absolutely want a second layer of nominal half-inch exterior glue plywood with no face of grade lower than C on top of what you've got, Dan. At least.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 09-03-2020, 09:31 PM   #82
arnav
Registered User
 
Join Date: Aug 2014
Location: FL
Posts: 319
The HD website was no help (doesn't show what's actually in stock) nor do I know exactly what I am looking for so I'll pay them a visit tomorrow and see what they have.

I did find this over the top marine grade AB plywood
https://www.homedepot.com/p/AB-Marin...6540/202084532

1. Skip PT ply?

2. Out of curiosity what does removing the sub-floor entails? Could you just cut out the portion within the room's interior (up to the walls) and block/support the seam underneath with a 2 x 4?

Thanks for all the help
__________________
Dan
Much like this project, my posts are still under construction

Last edited by arnav; 09-03-2020 at 09:39 PM.
arnav is offline   Reply With Quote
Unread 09-03-2020, 09:42 PM   #83
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 90,953
1. Absolutely.

2. If you do that you'll still need two new layers of subfloor. But yes, you just cut out what you have and install new subfloor with adequate blocking all around.

Your Homer's should have some BC grade plywood that will have a grade stamp saying EXT or Exposuer 1 on it somewhere. That's all you need.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 09-03-2020, 10:27 PM   #84
arnav
Registered User
 
Join Date: Aug 2014
Location: FL
Posts: 319
thank you very much for the details of what I am looking for. I bought ply before but just for interior type projects.

1.
Quote:
Originally Posted by cx
If you do that you'll still need two new layers of subfloor
You mean subfloor and underlayment right? The previous ones were each 3/4".

2. If you take out the subfloor, I am assuming you would stagger the underlayment on top?
For example, the bathroom dimensions are 7.5' x 5'
- The subfloor could be two pieces 4' x 5', 3.5' x 5'
- The underlayment would then be two pieces 7.5' x 2.5'

3. Cut 1.5" inches away from the wall (i.e. if using a circualr saw) or use a sawzall to cut flush with the wall? If the latter, that suggests you will need to drive nails to the blocking through the metal studs sole plate (which may be ok, not sure). While it will not cut flush with the wall, a circular saw on a 2x4 runner will not dive into the crawl space which has large AC ducts and 4" PVC pipes i would hate to get close to.

4. Does anything goes between the subfloor and underlayment? Right now there is some sort of paper product in between (thickness of a poster board).
__________________
Dan
Much like this project, my posts are still under construction
arnav is offline   Reply With Quote
Unread 09-04-2020, 06:42 AM   #85
ss3964spd
Moderator
 
ss3964spd's Avatar
 
Join Date: Jul 2005
Location: Fairfax, Va
Posts: 3,427
Send a message via Yahoo to ss3964spd
Underlayment is what the tile will be adhered to, Dan. The subfloor is your plywood, even if you have two layers of plywood, which you will, onna count of your w i d e joist spacing.

If you remove and replace the subfloor, and then add a second layer of ply, you definitely want to off-set the seams by about 6". You also want to install both layers so that the long edge of the ply is perpendicular to the joists. In all cases, you want to use as large a sheet as possible and practical.

You can use a circular saw but of course it's not going to get into the corners, so the sawzall is coming out anyway. definitely easier to control blade depth with the circ, but then that leaves you with 2 some inches of old plywood around the perimeter that you'll have to hope your new ply will closely match in thickness.
__________________
Dan
---------------------------------------------------------------------------------
If I recall correctly my memory is excellent, but my ability to access it is intermittent.
ss3964spd is offline   Reply With Quote
Unread 09-04-2020, 07:33 AM   #86
arnav
Registered User
 
Join Date: Aug 2014
Location: FL
Posts: 319
I misunderstand the basic terminology then.
Originally I had 2 layers of ply + CBU.

I thought:
- First layer of ply is the sub-floor
- Second layer of ply is the underlayment
- CBU is CBU...

Based on your post i think its really:
- Two layers of ply is the sub-floor
- CBU is the underlayment for the tiles.
- if we were laying carpet for example, the underlayment would be the foam thingy they put underneath

Did i get this right now?

You are not suggesting that if I replace the subfloor I would have 3 layers of ply, are you?
I would still have 2 layers of ply + CBU yeah?
__________________
Dan
Much like this project, my posts are still under construction
arnav is offline   Reply With Quote
Unread 09-04-2020, 07:42 AM   #87
ss3964spd
Moderator
 
ss3964spd's Avatar
 
Join Date: Jul 2005
Location: Fairfax, Va
Posts: 3,427
Send a message via Yahoo to ss3964spd
You've got it, Dan. In your case the CBU - because that's what you've elected to use, becomes the tile underlayment. So, the layers you will end up with are 3/4" tongue and groove ply, a minimum of 1/2" ply, mortar, CBU, mortar, tile.
__________________
Dan
---------------------------------------------------------------------------------
If I recall correctly my memory is excellent, but my ability to access it is intermittent.
ss3964spd is offline   Reply With Quote
Unread 09-04-2020, 08:08 AM   #88
arnav
Registered User
 
Join Date: Aug 2014
Location: FL
Posts: 319
so my last few posts probably made no sense (or i possibly mislead you about what I) actually did). Thanks for bearing with me. I can't edit these posts anymore, so I'll just recap again to be on the safe side and to keep the "record" accurate.

Quote:
Originally Posted by arnav
More importantly, as you can see the underlayment and sub-floor by the tub are gone.
So the CBU underlayment was totally fine. What you see here is the damage to the second subfloor layer / ply (now removed).
Attached Images
 
__________________
Dan
Much like this project, my posts are still under construction
arnav is offline   Reply With Quote
Unread 09-04-2020, 08:10 AM   #89
arnav
Registered User
 
Join Date: Aug 2014
Location: FL
Posts: 319
Quote:
Originally Posted by arnav
I took out half the underlayment where there was rot.
No. I took out the the top / 2nd layer of the sub-floor that was rotted. What you see here is the damage to first sub-floor layer / ply (not removed).
Attached Images
  
__________________
Dan
Much like this project, my posts are still under construction
arnav is offline   Reply With Quote
Unread 09-04-2020, 08:29 AM   #90
arnav
Registered User
 
Join Date: Aug 2014
Location: FL
Posts: 319
and this is the current state of affairs.

So ultimately what I meant to ask and what I am currently contemplating is whether to replace just the top layer of the subfloor throughout or remove the subfloor in its entirety...
Attached Images
   
__________________
Dan
Much like this project, my posts are still under construction
arnav 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
Ghibli Bathroom for Kids quinocampa Tile Forum/Advice Board 32 08-18-2016 10:35 AM
Kids Bathroom wagsgt Tile Forum/Advice Board 121 02-01-2016 09:26 AM
Kids Bathroom Question dalasgalas Tile Forum/Advice Board 1 05-31-2014 08:35 PM
Kids Bathroom Redo jtraggie99 Tile Forum/Advice Board 22 03-24-2014 04:03 PM
Darin's Kids' Bathroom Project SuperJETT Tile Forum/Advice Board 18 06-01-2009 11:33 AM


All times are GMT -6. The time now is 05:41 PM.


Sponsors

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