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 06-06-2017, 09:55 AM   #1
bgronski
Registered User
 
Join Date: May 2004
Location: Andover, Minnesota
Posts: 60
Floor truss deflection

I went to look at a job last Friday. Homeowner is allergic to many things, and have pulled most all carpet from the second floor of the house and are ready to have it all tiled.

The kitchen, dining area, laundry and garage entrance are covered in ceramic tile over CBU. The first thing I noticed when I walked in was where every CBU seam is, because the tile and grout are all cracked around the perimeter of every sheet! The homeowner said that all happened within the first two years, and has been that way for the past 15 years.

I immediately figured it to be a deflection problem, and they want to install slate in replacement of the ceramic. In going downstairs to see what the floor is framed out of, I found floor trusses spanning 18' spaced 16 inches apart.

To my dismay the deflectometer will not help me in this situation! I have been researching what I need to do, and am confused at best. The homeowner was unable to find any tags or labeling on who manufactured the trusses. In his research he thinks the company has folded during the recession. Short of hiring an engineer we are at a loss of what to do now? I have read in some forums that sistering 2x lumber, or plywood will be needed, others say a 2nd layer of 3/4" will suffice. Not anything I want to be guessing at, and run into warranty issues down the line.

Any help would be greatly appreciated!
__________________
Brian Gronski
Taconite Tile & Home Improvement
bgronski is offline   Reply With Quote
Sponsored Links
Unread 06-06-2017, 10:32 AM   #2
wwhitney
Registered User
 
Join Date: Dec 2015
Location: Berkeley, CA
Posts: 1,100
A couple semi-informed/semi-guess comments:

I don't see why a deflection issue would cause failures only at the perimeter of the cement board. It's not like the deflection is going to be significantly greater at the cement board seams. So it could be an installation error on the cement board, like not taping the seams or not bedding the board in thinset. A little destructive inspection would show if those errors were made.

As to the floor trusses, obviously it would be best to identify the manufacturer and model and get the original design data from the manufacturer (or their back catalogs, if they are out of business). Failing that, you could measure the trusses to determine the size of each member, spacing, pattern of chords, etc. Then if you can find a current manufacturer that makes something substantially identical, you could use their deflection info as a rough estimate of the existing trusses.

Cheers, Wayne
__________________
Wayne
wwhitney is online now   Reply With Quote
Unread 06-06-2017, 10:36 AM   #3
wwhitney
Registered User
 
Join Date: Dec 2015
Location: Berkeley, CA
Posts: 1,100
P.S. A rough estimate of wood truss deflection can be had as twice the deflection of a beam whose moment of inertia is computed from just the top and bottom chord. So if you can provide the top and bottom chord member sizes (2x4), species and grade (or best guess), truss depth, and span (18'), that would be a simple calculation to make.

Cheers, Wayne
__________________
Wayne
wwhitney is online now   Reply With Quote
Unread 06-06-2017, 10:16 PM   #4
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 91,257
Quote:
Originally Posted by Brian
The first thing I noticed when I walked in was where every CBU seam is, because the tile and grout are all cracked around the perimeter of every sheet!
Brian, the first thing I'd check would be whether the CBU was properly installed with thinset mortar under the panels and the seams filled and taped with alkali resistant mesh tape.

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

Similar Threads
Thread Thread Starter Forum Replies Last Post
deflection and floor truss 55tbirdfan Tile Forum/Advice Board 9 03-06-2015 10:13 AM
Help! Taking deflection out of a Truss floor lacknothing Tile Forum/Advice Board 5 08-16-2012 11:20 PM
Deflection on Truss question luca99 Tile Forum/Advice Board 3 10-19-2009 04:49 AM
Deflection for Truss construction kd55341 Tile Forum/Advice Board 5 08-18-2009 05:01 PM
Truss Deflection PAINT Tile Forum/Advice Board 13 11-13-2004 04:34 PM


All times are GMT -6. The time now is 11:03 PM.


Sponsors

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