I often find CD material to be erroneous and misleading. I wouldn’t trust any of their graphics or images without verifying them through a reputable source.
Just my opinion.
2x4 or as it should be called, a 1 5/8 by 3 5/8 +/- 1/8
The article states: *“The 2012 International Residential Code does not require collar ties (or collar beams).” *
That is not correct. 2012 IRC R802.3.1 states “Collar ties shall be a minimum of 1 inch by 4 inches (25 mm by 102 mm) (nominal), spaced not more than 4 feet (1219 mm) on center.”
Furthermore, the requirements for nailing are specified in IRC Table R602.3(1) and an illustration is provided in FIGURE R802.5.1.
Joe, setting a minimum size and spacing for something is not the same as requiring something.
Hi, Joe. Not all roof structures require collar ties. Code does not require collar ties (or collar beams) to be installed in every situation. Think of an open cathedral ceiling, for example. However, in those situations when they are needed, code specifies them.
Codes often specify how to do something, if you do it, without requiring you to do it.
But are we in agreement though that if collar ties aren’t used than brackets / connectors are needed to serve the same purpose of preventing uplift.
Ben, in your example, there will need to be a ridge beam in lieu of a ridge (board) for a cathedral ceiling and rafters tied to it w/ brackets. So there are no collar ties required but there is a replacement serving the same purpose.
That’s a good graphic. I agree, without collar ties, the rafter tops should be secured to the beam with hardware, not just toenailing.
So to put the Canadian thing to bed Marcel is correct and so is Carson Dunlop in this case. I am not a CD fan but when in Canada… they are correct.
A collar tie is an intermediate support and a ceiling joist or rafter tie is installed on top of the wall and nailed to the joist. They are both considered to stop spread. I feel you need both because a collar tie also prevent deflection. So now you guys know about the only thing I remember from carpentry school!! LOL
The word “intermediate” in math means between two points but not necessarily the exact middle of them.
Would 1/3 qualify as intermediate in your math?
Deflection or sagging is not prevented by the Collar Ties that are supposed to be in the upper 3rd of roof frame. Collar Ties prevent rafter uplift separation not deflection of the roof frame.
If you want deflection, sagging prevention for rafters you add purlins below over spanned rafters w/ bracing up to those purlins every 4’ max off of walls or beams but not off of ceiling frame.
Nick might be right.
Intermediate is defined as; being, situated, or acting between two points, stages, things, persons, etc.: the intermediate steps in a procedure.
1/3 is a point inbetween two points as well as 1/2. Just intermediate between the two.
:)
LOL Marcel !
Assuming you’re Canadian and hired [FONT=Verdana]Nick The Contractor to install collar ties as per good building practices (NBC 9.23.13.7.) and noticed the collar ties were installed at the 1/3 mark up the rafters instead of intermediate, in between, middle, and his explanation for deviating from the code was:[/FONT]
The word “intermediate” in math means between two points but not necessarily the exact middle of them.
Would you be satisfied with his answer or would you fire him?:p;-)
LOL…
That is why collar ties are positioned halfway - midway - in-between - in the middle of the rafters, to prevent deflection or sagging.
Wrong…not the purpose of the collar ties. Try getting some more information on this Marcel, CD ain’t cuttin it for ya.
It is here due to snow load contrary to where you are.
Like I said, its a Canadian thing…
If that is the case, the correct term for a mid-point horizontal brace would be a rafter tie. Normally a purlin system would be used or properly sized rafters.
Attached is a pic from Canadian Wood Frame Construction by Canadian Mortgage and Housing Corporation (CMHC) which reads in part:
(A) ceiling and roof framing with ridge board;**
**(1) each rafter toenailed to ridge board with four 2¼ in. (57mm) nails
or end-nailed with three 3¼ in. (82mm) nails;
(2)1x4 in (19x89mm) strip nailed to top of collar braces at their centre with
two 2¼ in (57mm) nails when the braces are more than 8ft. (2.4m) long;
(3) ceiling joists butted with splice plate over centre bearing partition. Joists
also nailed to each part of rafters (see [Table 27](file:///C:/CMHC%20Wood%20Frame%20House/english/book/appendix/table27/index.htm) for nailing practice);
(4) collar brace used as internediate support for rafters nailed to each
pair of rafters with three 3 in. (76mm) nails at each end;
(5) ceiling joists toenailed to top wall plate with two 3¼ in (82mm) nails, one each side;
(6) rafter nailed to plate with three 3¼ in. (82mm) nails;
[collar tie](file:///C:/CMHC%20Wood%20Frame%20House/english/features/illustrations/print/fig54.htm) (entrait retroussé, m.) A horizontal member used to provide intermediate support for opposite roof rafters, usually located in the middle third of the rafters. Also called collar beam or brace.
