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 01-14-2019, 05:03 PM   #1
Olivrae
Registered User
 
Join Date: Jan 2019
Posts: 3
Yet another subfloor question

Hi, new to the list. trying to get some advice on my floor.

In the planning stages of a 2nd flr master bath with only studs and rough plumbing currently. The subfloor(3/4" T&G) sits on a 15' span made up of 2x10 12"OC. The deflecto tells me I'm L386. I'd like to add additional underlayment for some breathing room.
I can't find a calculator for how much I can improve the stiffness (glueing, screwing and offsetting edges) by adding another layer of plywood.

Any insight would be appreciated and look forward to the help I'm sure to get here. Thanks!

Dan
__________________
Dan
Olivrae is offline   Reply With Quote
Sponsored Links
Unread 01-14-2019, 06:30 PM   #2
Tool Guy - Kg
Moderator -- Wisconsin Kitchen & Bath Remodeler
 
Tool Guy - Kg's Avatar
 
Join Date: Feb 2005
Location: Oak Creek, WI
Posts: 21,675
Welcome to the forum, Dan.

The Deflecto calulator calculates the joist structure only (which you're reporting at L/386). Adding plywood layers to the top doesn't increase this structural value. If you want the structural value to go up, you need to use more joist material (or add plywood to the underside of the joists using specialized, and rarely used techniques). I plugged in your figures into the Deflecto and am coming up with a different calculation. I must be using different values or wood species or spacing or span than you, so....

1) Can you clarify which values you're using for the Deflecto, and
2) I'll ask if there's anything specific you're concerned about, and
3) Can I confirm that you're planning to use man-made ceramic/porcelain tiles, and
4) Can I ask which tiling method you're planning to use?

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

Help an awesome summer camp!
Tool Guy - Kg is offline   Reply With Quote
Unread 01-14-2019, 07:33 PM   #3
muskymike
Retired Moderator -- Wisconsin Tile Man & Musky Guide
 
muskymike's Avatar
 
Join Date: Apr 2004
Location: Springbrook WI
Posts: 16,083
Send a message via Yahoo to muskymike
Hi Dan welcome. I agree with Bubba. I ran your measurements through the Deflecto and come up with 424 which it good for ceramic or porcelain. Adding more subfloor doesn't add strength to the joists.
__________________
Musky Mike
Corrado Custom Tile
Kerdi Shower Specialist
Dreams are like tasting a little bit of the future today. Keep dreaming and it will come true.

New here? Check this out.

muskymike is offline   Reply With Quote
Unread 01-14-2019, 08:01 PM   #4
Olivrae
Registered User
 
Join Date: Jan 2019
Posts: 3
Thanks for the replies.

To be more specific the span is 15'6".
I plan to use a porcelain tile over Ditra. Not sure on the tile size since I'm assuming the smaller the better if the floor deflects a bit. wondering if 12x12 are too large.

Dan
__________________
Dan
Olivrae is offline   Reply With Quote
Unread 01-14-2019, 08:11 PM   #5
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 89,568
Welcome, Dan.

First, do you actually know that your joists are Douglas Fir or Southern Yellow Pine and are of good grade? If not, your calculations might be much better than your joist structure.

Second, the size of your tiles has nothing at all to do with the floor deflection requirement. What will matter a great deal is the flatness of your floor, especially if you select a large format tile.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is online now   Reply With Quote
Unread 01-15-2019, 09:58 AM   #6
Olivrae
Registered User
 
Join Date: Jan 2019
Posts: 3
They are No. 2 SYP in good shape. The joists have 1x3 strapping 12"OC. It's 20yo construction.
__________________
Dan

Last edited by Olivrae; 01-15-2019 at 01:07 PM.
Olivrae 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
Another subfloor question MGJ Tile Forum/Advice Board 26 03-26-2014 05:19 PM
Newbie Deflecto question and subfloor question. gonemob Tile Forum/Advice Board 2 09-19-2012 02:12 PM
Another subfloor question Alex S Tile Forum/Advice Board 3 01-27-2008 12:53 PM
Transistion question and subfloor question KurtH Tile Forum/Advice Board 4 11-17-2005 11:07 AM
And yet, another subfloor question kiefer Tile Forum/Advice Board 4 12-18-2002 07:49 AM


All times are GMT -6. The time now is 02:01 PM.


Sponsors

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