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 12-30-2020, 05:46 PM   #16
mykcuz
Registered User
 
Join Date: Aug 2020
Posts: 68
I'm sorry, but the screws aren't simply holding two pieces of lumber together, they are creating a beam and sharing shear loads as weight is added and removed above. (Live load)

If using framing nails, you would have to glue and then nail rows of 4 nails every 16" from both sides, typically on a triple(yes I know he's discussing a double), whereas a structural screw would be installed in pairs of 2, sometimes 3, with spacing varying from 16-24" from inky one side.

So yes, you could substitute deck screws and use 4 times as many plus washers(which aren't actually spreading the load properly, or you could simply pickup a box of the correct fasteners with washer heads, and have the proper strength for the life of the floor.

Again, speak to an architect/ engineer for 30 seconds and you'll have your answers.

Sent from my SM-G950U using Tapatalk
__________________
Mike
mykcuz is offline   Reply With Quote
Unread 12-30-2020, 06:18 PM   #17
cx
Moderator emeritus
 
cx's Avatar
 
Join Date: Jul 2001
Location: Boerne, Texas
Posts: 92,239
Mike, if the two pieces were not to be glued together I'd be more inclined to agree with your argument, but I don't recommend anyone ever do any structural sistering without using and adhesive between the pieces. The mechanical fasteners serve as gluing clamps as well as adding some structural value after the glue has cured. Not only does the glue provide the majority of the structural value in that application, but also virtually eliminates the problem of creep experienced with mechanical fasteners alone.

The decking screws are also more prone to breaking than are nails or some other structural fasteners, but I've never experienced that when using them for joist sistering.

My opinion; worth price charged.
__________________
CX

Y'ALL NEW VISITORS READ THIS HERE!
cx is offline   Reply With Quote
Unread 12-30-2020, 06:34 PM   #18
PC7060
...unrepentant, detail focused, over-analyzer.
 
PC7060's Avatar
 
Join Date: Jan 2013
Location: Virginia
Posts: 2,881
Quote:
Again, speak to an architect/ engineer for 30 seconds and you'll have your answers
As one of the engineers you reference, the word I would use if someone recommended SDWH screws for this application would be “overkill”. Many would argue my approach with screws and glue is also overkill.

The OP is simply sistering a second joist to improve stiffness of the floor to meet requirements of TCNA so we are recommending a cost effective method to meets that requirement.

Agree with you completely if we were specifying fastening schedule for main beams but that’s not the case here.

And in line with CX tag line....

Disclaimer: I am a structural engineer, but I'm not your structural engineer. Check with a local PE before you try anything I suggest.

(On this we agree, Mike! )

Last edited by PC7060; 12-30-2020 at 06:40 PM.
PC7060 is offline   Reply With Quote
Unread 12-30-2020, 06:37 PM   #19
ranchopedro
Registered User
 
Join Date: Jun 2004
Location: beautiful santa cruz valle of arizona
Posts: 21
Send a message via AIM to ranchopedro Send a message via Yahoo to ranchopedro
Quote:
Originally Posted by Damon
What do you recommend?
Start here and read a few of these
https://www.eng-tips.com/search.cfm?...earch&q=sister
I will guess a few LVLs are in your future
Dont go blindly ...get yourself a structural engineer to cast an eye (wont cost much)

If you dont know fasteners well GRKs are awesome, come with a bit, and will not cam out
For your task R4s may suffice ...with a nice impact
https://www.grkfasteners.com/
__________________
Pedro
ranchopedro is offline   Reply With Quote
Unread 12-30-2020, 06:42 PM   #20
PC7060
...unrepentant, detail focused, over-analyzer.
 
PC7060's Avatar
 
Join Date: Jan 2013
Location: Virginia
Posts: 2,881
Quote:
Originally Posted by Pedro
If you dont know fasteners well GRKs are awesome, come with a bit, and will not cam out. For your task R4s may suffice ...with a nice impact
Them’s some nice screws, Pedro.
PC7060 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 question about sistering joists Elvin Tile Forum/Advice Board 17 03-14-2010 05:01 PM
Deflection help - live load or total load jeffdeline Tile Forum/Advice Board 19 01-08-2006 10:22 AM
Sistering joists RR Tile Forum/Advice Board 13 04-14-2005 11:28 AM
Sistering DF solid joists with I-Joists: bad idea? MartinGFoster Tile Forum/Advice Board 8 12-05-2003 04:33 PM
sistering joists with 2x4 or 2x6? Bitzy Tile Forum/Advice Board 17 09-10-2002 06:01 AM


All times are GMT -6. The time now is 10:21 AM.


Sponsors

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