Deck joist spacing

[Jason in Sudbury]

Well, I helped my father start building his deck. We put the beams up and got them level this weekend. Next weekend, we are building the deck. :)

My father plans on using 5/4 cedar decking, and we are wondering if we should go 12" on center joists, or 16" on center joists? The deck will be 20X16. There are 3 triple 2x6 beams that run the 20' length. (the outer ones are 2' in and one at 8' (in the middle)...ie. 6' is the maximum span)
The joists will be 2x6 joists and the 5/4 deck boards will be running at 45 degrees to the floor joists.

So what kind of spacing should be used for the joists? Any other little things to look out for? Any ideas?

Thanks!

[Chris in Pickering]

Joists 16" oc makes a strong deck, no need to go 12" oc unless you are running the deck boards on a diagonal.... You run them on a diagonal and you are looking at a 16 or 17" span over 12" .
I like 2x8 joists for a rock solid deck, but I am a big horse....

[Jason in Sudbury]

Chris,
Thanks for the info.

Just to be clear, the deck boards (5/4") will be running on the diagonal.

[Chris in Pickering]

Chris,
Thanks for the info.

Just to be clear, the deck boards (5/4") will be running on the diagonal.


Than I would go 12" OC for sure!!!!

[Pete in Milton]

First what does the building code say??? next follow it for MINIMUM standards!!!! My personal experience 5/4 @ 16" centres is too bouncy, 2X6 @ 16" centres is great. My $.02

[billh]

Especially since the run is diagonally across the joists I would go with 12" centres. IMO, the cost of the extra material is trivial compared to the total cost of the job.

billh

[Jason in Sudbury]

We went shopping tonight, and 12" o.c. it is!

Thanks for all who replied!