Deck building: Sistering joists vs joist hangers on beam


  #1  
Old 05-27-20, 09:32 AM
S
Member
Thread Starter
Join Date: May 2020
Location: Canada
Posts: 3
Received 0 Votes on 0 Posts
Deck building: Sistering joists vs joist hangers on beam

I'm building my first deck and I have a question about long joists. I'm builidng an 18' deck, but I can only get 16' joists from my local supplier. I have a couple options and wanted to get opinions.

1. I can sister the joists.
2. I can set the center beam height equal to the ledger board and use joist hangers on either side of the center beam.

Any thoughts on which method is stronger? If I sister the joists, should I overlap two joists or should I butt 2 joists over the beam and then attach an additional 2x to both joists?
 
  #2  
Old 05-27-20, 11:31 AM
P
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 25,624
Received 973 Votes on 894 Posts
1. Do not sister joists to make them longer.
2. Design your deck to have more moderate spans. This probably will require a beam down the center of your deck.

The International Residential Code (IRC) has extensive information how to properly build a deck and others like the American Wood Council have published guides to help though the IRC is generally the law of the land. You can also contact your local building inspections dept. So many people screw up decks in my area that the building dept. has a handout just for DIY deck builders.
 
  #3  
Old 05-27-20, 10:03 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Location: USA
Posts: 27,369
Received 1,002 Votes on 911 Posts
I would suggest that if your deck will be 18ft long, that you special order your joists so they are continuous, and 18ft long. Any lumber yard can order them in. They stock 16'ers. They can order anything you want.

Then, I would suggest you use a joist over beam style of framing so that your joists are continuous. You could also utilize multiple beams to add to the stiffness and straightness of the deck. You just need to add solid blocking between joists directly over the beam.
 
  #4  
Old 05-28-20, 10:16 AM
S
Member
Thread Starter
Join Date: May 2020
Location: Canada
Posts: 3
Received 0 Votes on 0 Posts
Thank you for the links as they are very helpful. I have a beam going down the center of the deck at 9' from the house. With sistering the joists I would overlap two 12' joists over the beam at 9'. There would be a 6' overlap of the joists that would then be bolted together.

The other option is to call around and see if I can find 18' joists.
 
  #5  
Old 05-28-20, 10:25 AM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Location: USA
Posts: 27,369
Received 1,002 Votes on 911 Posts
Which is more work, doing all that unnecessary bolting? Getting and paying for 24' of joists when you only need 18? Or making a phone call and asking if your local lumber yard will order in the 18's?
 
  #6  
Old 05-28-20, 10:35 AM
S
Member
Thread Starter
Join Date: May 2020
Location: Canada
Posts: 3
Received 0 Votes on 0 Posts
Excellent point. I was trying to work with what I had aleady ordered from Home Depot. They didn't have anything bigger than 16', but I quick look around and I've found a lumber yard with 18' foot joists. Might be a little more expensive, but sounds worth it.

Thanks for the advice, it's greatly appreciated.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: