Which way joists?


Old 12-30-16, 03:03 PM
Thread Starter
Join Date: Dec 2015
Posts: 108
Received 0 Votes on 0 Posts
Which way joists?

In my garage I am trying to figure out which way the joists are running. It looks almost like they run differently on either side of the support but I am not sure. I have included a photo to help. The peak of the roof in to the left of the support but the spackling runs different as you can see.

Help appreciated in advance.
Thank you

Name:  20161230_163300.jpg
Views: 253
Size:  24.0 KB
Old 12-30-16, 03:25 PM
Marq1's Avatar
Join Date: Sep 2016
Location: USA MI
Posts: 6,905
Received 426 Votes on 397 Posts
It does appear that they run differently but not being able to see the exterior roof lines cant confirm.

Should have access somewhere, I'd take a peek!
Old 12-30-16, 03:32 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,965
Received 6 Votes on 6 Posts
I'll agree the back room seems to be running left to right while the fore room is perpendicular, and that's according to the sheetrock screw pattern. The long runs of mud are the factory edge of the sheetrock.
Old 12-31-16, 07:05 AM
Join Date: Jan 2011
Location: USA
Posts: 4,855
Received 83 Votes on 78 Posts
I think it looks like the run was longer than the sheetrock they used so the area near the beam was patched in.
Sure looks like the joist just run at a right angle to the beam and sit on top of it.
Old 01-01-17, 11:02 AM
Join Date: Feb 2006
Location: USA
Posts: 6,740
Received 22 Votes on 21 Posts
Joist Direction

Use a stud finder to locate the joists and determine direction.
Old 01-16-17, 05:02 PM
Join Date: Jan 2004
Location: Harrisburg, PA
Posts: 497
Received 0 Votes on 0 Posts
I'm not an expert, but isn't the reason the long support exists (going from left to right) is to hold up the joists? ...the joists must be resting on it.

Another way to verify is to remove the plate from the electrical outlet and pry around using a flashlight. Electrical boxes are fastened against a 2x4/6/8 the long way, so that electrical outlet confirms the joists are perpendicular to the long support (girder).

Another clue: I see the springs of the garage doors and this tells me which way the garage bay is running and garages are at least 20 feet deep. At 20 feet deep, the joists cannot be running parallel with that long support since you'd need a 21 foot joists ...which would be insane.

Again, I don't see a reason to install that long support if the joists wouldn't rest on it. So I'd say it's there for a reason and all joists are perpendicular to it, but I'm not totally sure.
Old 01-16-17, 05:32 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,965
Received 6 Votes on 6 Posts
Good analogy, Tony BUT

Sheetrock is never hung parallel to joists, as would be evidenced in the near portion.

My guess is this is either a hip type roof or it has a change of direction, making the joists go 90 degrees to the others. Without seeing the roof system, it would be a guess, however.
Old 01-16-17, 05:44 PM
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 36 Votes on 28 Posts
My guess is this is either a hip type roof...
That's my guess as well. I have the same pattern on my garage ceiling and I have hip roofs.
Old 01-16-17, 06:49 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Location: USA
Posts: 26,547
Received 784 Votes on 722 Posts
For all we know they could be very long web trusses, joists or i-joists running one way, half running the other. I would take 5 minutes and go in the attic and look.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: