joist size ???

  • Advertise with us

« back to Wood & Lumber forum

Forum topic by dustycajun posted 01-26-2016 06:41 PM 408 views 0 times favorited 7 replies Add to Favorites Watch
View dustycajun's profile


55 posts in 908 days

01-26-2016 06:41 PM

I am building a lean to, 12 foot wide , need suggestions on joist for roof , should i use 2×6 or would 2×8 be
Better. Im using a metal roof.

-- klcrd

7 replies so far

View jusfine's profile


2405 posts in 2350 days

#1 posted 01-26-2016 07:05 PM

Is 12’ the clear span from building to your beam?

It would also depend on the slope, if it is a low slope (3 or less), I would go 2×8. If more, 2×6 should be fine.

In Canada we have to consider snow load, doesn’t look by your location like that is an issue…

-- Randy "You are judged as much by the questions you ask as the answers you give..."

View bigblockyeti's profile


3587 posts in 1144 days

#2 posted 01-26-2016 07:10 PM

Houma isn’t likely to see too much snow any time soon so 2×6 would work, the steeper the pitch the better (within reason). I would personally still prefer to use 2×8 for the joists just for greater strength.

View Smitty_Cabinetshop's profile


13575 posts in 2042 days

#3 posted 01-26-2016 07:12 PM

Rule of thumb: distance divided by two is dimension lumber need, rounding up in every case. 12’ means 2×6 is minimum. Metal roof lightweight. I’d say it’s fine. Consult building codes, etc. as necessary.

-- Don't anthropomorphize your handplanes. They hate it when you do that. -- OldTools Archive --

View MrUnix's profile (online now)


4049 posts in 1623 days

#4 posted 01-26-2016 07:14 PM

Depends on the load. I used 2×6 (actually, I just ripped a 2×12 in half) on a 14 foot span for my pole barn, but it’s a pretty light roof and we don’t need to worry too much about snow down here in Florida :)

I don’t think going bigger would hurt, but going smaller might!


-- Brad in FL - To be old and wise, you must first be young and stupid

View bondogaposis's profile


3972 posts in 1775 days

#5 posted 01-26-2016 07:16 PM

What is your snow load? Here it is 34 lbs/sqft. Okay, I take that back I see you are in LA. My guess 2×6 will adequate.

-- Bondo Gaposis

View conifur's profile


955 posts in 575 days

#6 posted 01-26-2016 07:50 PM

Also consider the distance between each one. 16 or 24 on center? That also needs to be factored in.

-- Knowledge and experience equals Wisdom, Michael Frankowski

View dhazelton's profile


2294 posts in 1720 days

#7 posted 01-26-2016 08:34 PM

12 wide but how deep? Run your joists the short way and you could get by with smaller lumber.

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics