Almost as good as mine Nick
Actually I do have my Nachi images in my article.
Marcel, upper 3rd for collar ties and lower third for rafter ties ! I think I remember hearing it was different in Canada though ?? Maybe??
You’ve got rafter ties whether you know it or not if joists are running same direction as rafters and fastened together on the top plate.
Yep, ceiling joists are the rafter ties if they are parallel to the rafters. I was schooled on this by an engineer 20 years ago. There are a lot of stick framers out there that still think the collar ties prevent rafter/wall spread.
Where did that graphic come from, because it is wrong.
Carson Dunlop which are a well known engineering and inspection firm.
Must be a Canadian thing.
What part(s) do feel is wrong?
The collar tie is to be in the top third of the rise. Don’t know if it is different in Canada, but I doubt it.
The Carson Dunlop image Marcel posted is incorrect IMHO.
Thanks. I thought this is what you may have been referring to. It almost appears to be in top third in graphic, but the 5’ reference throws it off.
The National Building Code 22.214.171.124. reads in part:
*Intermediate Support for Rafters and Joists
- Ceiling joists and collar ties of not less than 38 mm by 89 mm lumber are permitted to be assumed to provide intermediate support to reduce the span for rafters and joists where the roof slope is 1 in 3 or greater.*
So, it must be a Canadian thing…
I still fail to see how this statement has anything to do with collar tie placement. Is there more?
Must be a Canadian thing ! What the hell is 38mm by 89mm?
Check out the definition of intermediate.
Hell do I know, sounds like a 2 X 4…
Hm, I see your point.
Intermediate - lying or occurring between two different points, or extremes.
Does not mean exactly at mid-point. Inconclusive
1in·ter·me·di·ate. adjective \ˌin-tər-ˈmē-dē-ət. : occurring in the middle of a process or series. : relating to or having the knowledge or skill of someone who is …