Washers For Bolts Used In Sistering - Building & Construction - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Building & Construction

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 01-19-2012, 09:08 PM   #1
Newbie
 
Join Date: Jan 2012
Posts: 3
Rewards Points: 10
Question

Washers for bolts used in sistering


Old Geezer that I am, the following info would be welcome. I plan to bolt sisters to 7 beams/floor joists. The beams a just a little less than 8" and a little more than 2 1/4" or 2 1/2 inch. So far the bolt dia. will be 5/16". I plan to use 6 washers per bolt, 5/16, 7/16, & 7/8. Is this considered optimum/correct? One each of the previous on each side, plus construction glue.

Advertisement

BluGator is offline   Reply With Quote
Old 01-19-2012, 09:16 PM   #2
Member
 
Join Date: Nov 2011
Location: Hartfield VA
Posts: 27,815
Rewards Points: 746
Default

Washers for bolts used in sistering


Your post makes 0 since to me, why all the washers?
Use 1/2 carrage bolts not 5/16 and you will only need one 1/2 washer.

Advertisement


Last edited by joecaption; 01-19-2012 at 10:00 PM.
joecaption is online now   Reply With Quote
Old 01-19-2012, 09:20 PM   #3
Disabled wood vet
 
titanoman's Avatar
 
Join Date: Nov 2011
Location: California
Posts: 1,646
Rewards Points: 1,000
Default

Washers for bolts used in sistering


Quote:
Originally Posted by joecaption
Your post makes 0 since to me, why all the washers?
Use 1/2 carrage bolts not 5/16 and you will only need one 1/2 washer.
I've never heard of needing sistered joist for just an 8" foot span. Even a 2 X 6 can span that far, what's up with that?
I think he is saying the joists are 2-1/2" by 8". He doesn't say how far they are spanning.
titanoman is offline   Reply With Quote
Old 01-19-2012, 09:51 PM   #4
Member
 
Join Date: Nov 2011
Location: Hartfield VA
Posts: 27,815
Rewards Points: 746
Default

Washers for bolts used in sistering


Opps your right I need to get new glasses.
So what do you think about the rest of his ideas?

Last edited by joecaption; 01-19-2012 at 10:01 PM.
joecaption is online now   Reply With Quote
Old 01-19-2012, 09:55 PM   #5
Disabled wood vet
 
titanoman's Avatar
 
Join Date: Nov 2011
Location: California
Posts: 1,646
Rewards Points: 1,000
Default

Washers for bolts used in sistering


I think he just needs fender washers if he's wanting to put bolts into rotted wood. Other than that, I don't know what he's thinking.
titanoman is offline   Reply With Quote
Old 01-19-2012, 10:02 PM   #6
Newbie
 
Join Date: Jan 2012
Posts: 3
Rewards Points: 10
Question

Washers for bolts used in sistering


Sorry for the misconception (sp). The original joists are mid to late 1800's. They very from 7' to over 24' in length. They are 2 1/4" wide to 2 1/2" wide. Their are 7 3/4" high. They had notches cut in them in 1930 when plumbing was added to the house. The notches were cut by plumbers. We are attempting to sister 7' lengths. The washers are to preclude damaging the sister and original joist beam. A precaution noted on another web site. I need to find out the three staggered dia. Any ideas?
BluGator is offline   Reply With Quote
Old 01-19-2012, 10:17 PM   #7
Member
 
Join Date: Nov 2011
Location: Hartfield VA
Posts: 27,815
Rewards Points: 746
Default

Washers for bolts used in sistering


Are you aware a 2 X 8 is only good for about a 7 ft. or less span?
http://www.awc.org/calculators/span/...orizontal+Span
joecaption is online now   Reply With Quote
Old 01-21-2012, 12:17 AM   #8
Registered User
 
Join Date: Mar 2009
Posts: 10,016
Rewards Points: 2,098
Default

Washers for bolts used in sistering


"I need to find out the three staggered dia. Any ideas?"------ I don't know where you got that information....
As Joe said, 1/2" are usually used as a minimum. The washers fit the bolt, one on each side for max. strength. Stacking the washers in varying sizes does nothing. Bolt just the ends if using the sister for carrying the whole load, bolt in a staggered pattern down the length for helping the original (both joists) carry the load, there are restrictions and further help we can supply.
2 x 8 are fine sistered to old, #2 grade will span 10', only a #3 grade won't--- 40# per square foot chart, find the grade and species: second chart down; http://publicecodes.citation.com/ico...002_par017.htm

Gary
__________________
If any ads are present in my answer above, I do not condone/support/use the product or services listed, they are there against my permission.
Gary in WA is offline   Reply With Quote
Old 01-21-2012, 08:21 AM   #9
Newbie
 
Join Date: Jan 2012
Posts: 3
Rewards Points: 10
Default

Washers for bolts used in sistering


Thanks everyone. We accomplished most of the sistering yesterday. I would take me a small book to totally explain everything we have done. Your responses have been helpful. Stay out of the snow, freezing rain, and rain. Keep warm.
BluGator is offline   Reply With Quote
Old 01-21-2012, 09:17 AM   #10
Retired carpenter
 
Join Date: Dec 2011
Location: Portland, Oregon
Posts: 303
Rewards Points: 250
Default

Washers for bolts used in sistering


Adding gradually larger washers will decrease the pressure on the wood around the bolt. (I would also use just 1/2" bolts with 1/2" washers, and if the wood gets a bit crushed under the washer, so be it.)
abracaboom is offline   Reply With Quote
Old 01-21-2012, 09:35 AM   #11
Disabled wood vet
 
titanoman's Avatar
 
Join Date: Nov 2011
Location: California
Posts: 1,646
Rewards Points: 1,000
Default

Washers for bolts used in sistering


Quote:
Originally Posted by abracaboom
Adding gradually larger washers will decrease the pressure on the wood around the bolt. (I would also use just 1/2" bolts with 1/2" washers, and if the wood gets a bit crushed under the washer, so be it.)
How would it decrease pressure? Wouldn't the pressure transfer through any amount of washers?
titanoman is offline   Reply With Quote
Old 01-22-2012, 03:39 AM   #12
Retired carpenter
 
Join Date: Dec 2011
Location: Portland, Oregon
Posts: 303
Rewards Points: 250
Default

Washers for bolts used in sistering


Quote:
Originally Posted by titanoman View Post
How would it decrease pressure? Wouldn't the pressure transfer through any amount of washers?
The same force applied over a larger area means less pressure. Pressure equals force over area (pounds per square inch). Same force, more square inches: less pressure.
abracaboom is offline   Reply With Quote
Old 01-22-2012, 08:50 AM   #13
Disabled wood vet
 
titanoman's Avatar
 
Join Date: Nov 2011
Location: California
Posts: 1,646
Rewards Points: 1,000
Default

Washers for bolts used in sistering


Quote:
Originally Posted by abracaboom

The same force applied over a larger area means less pressure. Pressure equals force over area (pounds per square inch). Same force, more square inches: less pressure.
That makes sense. Thanx.

Advertisement

titanoman is offline   Reply With Quote
Reply


Thread Tools
Display Modes

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sistering Bouncy Floor Joists SimpleFix Building & Construction 28 10-08-2012 06:52 AM
sistering joists micparks Flooring 6 12-30-2011 10:18 PM
80-year-old apartment buildings, washers, DFU values, FUD WillisBlackburn Plumbing 4 09-18-2011 06:25 PM
Can two washers drain into one utility sink? mcru Plumbing 6 07-26-2010 09:23 PM
Sistering a floor joist? teachtech Building & Construction 8 02-19-2008 10:35 PM




Top of Page | View New Posts