cathedral ceiling wall height questions

[jhivy]

I am building a 16 ft wide story and a half with a loft in one end, cathedral ceiling in the other.  From what I've read in this forum, I can't go taller than 10 ft walls with a cathedral ceiling (without a ridge beam). That makes for less room in the loft end than I would like.  Can the walls be taller if i use collar ties at the top of the lower third of of the rafters in the cathedral end?  Also can I skip the collar ties on every other rafter and double the ties on every other rafter? That would be more aesthetically pleasing to me.  Thanks.

[Squirl]

I don't know where the picture came from, but those aren't collar ties.  Collar ties prevent the rafters from coming apart at the ridge board.

Collar ties or ridge straps to resist wind uplift shall be connected in the upper third of the attic space in accordance with Table R602.3(1).

Collar ties shall be a minimum of 1-inch by 4-inch (25 mm by 102 mm) (nominal), spaced not more than 4 feet (1219 mm) on center.

http://publicecodes.cyberregs.com/st/ny/st/b400v10/st_ny_st_b400v10_8_sec002.htm?bu2=undefined

If not using a truss or ridgebeam, rafter ties are required to be in the lower third of every rafter. 

[jhivy]

You are correct.  I meant rafter ties.  I was mislead by the incorrect label on the diagram.  I am not bound by any building code but don't want to do anything unsafe.

[MountainDon]

There is lots of confusion between the terms "collar ties" and "rafter ties".

Here's a straightforward pictorial depiction with labeled components.

[MountainDon]

From what I've read in this forum, I can't go taller than 10 ft walls with a cathedral ceiling (without a ridge beam).

The 10 ft wall height is the unbraced height that code permits. That is, if the wall is to be higher than 10 feet it must be laterally supported.

http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_6_par010.htm
Scroll down to  TABLE R602.3(5) SIZE, HEIGHT AND SPACING OF WOOD STUDS

A ceiling or floor at that height makes a good lateral support. With tall side walls and a cathedral ceiling that could also be cross ties of some type from one side wall to the other side wall. An engineers advice would be required.

A ridge beam solves the problem of the outward horizontal forces created by standard rafters, but a ridge beam does not automatically translate to building walls taller than 10 feet without any lateral supports at all. Unless your engineer designs it and blesses it.

[MountainDon]

Also can I skip the collar rafter ties on every other rafter and double the ties on every other rafter? That would be more aesthetically pleasing to me.

By code that could be permitted by the phrase  "designed in accordance with accepted engineering practice"  which appears sprinkled about the IRC in many footnotes. It offers a way to design and build something that does not appear in the book. Always read the footnotes.

[SouthernTier]

Why not go with a ridge beam? Sure an LVL or two is more expensive than a 2x10 or a 2x12 ridge board. But in the grand scheme of things it would be small potatos and even may save you some money by skipping all those rafter ties. You just need to follow the load down in the gables.