[SilentJane]

I have a ranch home and need storage. I want to remove the collar ties in my attic. Advice welcome! I live in the Northeast, snow load of 60. Ceiling joists run w rafters, 16 oc. 28 foot roof span, 6 on 22 pitch. My 2x6 collar ties are almost 4' above floor EVERY 16 inches. Major pain!

 

[SilentJane]

drawing of existing conditions-

 

[Bud9051]

We will need those pictures, may have to get a few more posts to be allowed to post them.

6 on 22 does not compute?? Was that supposed to be 6 on 12?

Are these trusses, the 28' span?

Bud

 

[SilentJane]

28'span, 6 on 12 lol

 

[SilentJane]

drawing of existing

 

[motoriderx7x]

Size of the rafters and size of the ceiling joists? I'm assuming the ceiling joists are about 14-15' and tied in on a center wall in the house?

 

[SilentJane]

the rafters are 2x6 16oc. is the drawing visible yet?

 

[SilentJane]

>I could be wrong w the pitch, but roof is 28 wide, outside wall to outside wall w inside of peak at 6' 8" or so. No center posts in attic, yet there is a center wall below the ceiling joists which are parallel to rafters, @16oc.

 

[Daniel Holzman]

The purpose of collar ties is to equalize uplift pressure between the two sides of the roof during high wind events. Usually the collar ties are spaced every 48 inches (every third rafter), apparently in your case they are on every rafter. Depending on the code and version you are subject to, collar ties may or may not be required. Regardless of code, they may save your roof during strong winds, and I do not recommend removing them.

 

[SilentJane]

I was more concerned w snow load, but wind is certainly a factor not to be ignored! ty.

Could adding one collar tie, a two by 4, every four feet just under the ridge and at the the same 4 feet, and adding posts similar to an attic type truss then tying them into the ceiling joists... and bracing from rafter to parallel rafter equate to the same thing? I'm no engineer so your thoughts are very welcome.

 

[ront02769]

While we may have thoughts, you really need an engineer.. Lots of factors to consider! Ron

 

[carpdad]

For that span of the roof "rafters", 2x6 rafters will sag if you remove the ties. Every other rafters may be fine, but it's possible for unsupported rafter to sag enough to see.

 

[Gary in WA]

Welcome to the forums! IF you are not in a high wind area, the collar ties may not be required. BUT, as the rafters appear under-sized for the span, they may be helping somewhat...IMO, not much as they can sag a great deal before enough resistance from opposite rafter deflection is usable. Code probably doesn't require them- based on your snow load; http://myconco.com/ComEngProb.html
Check with local AHJ.

As you have ceiling joists, the collar ties are to high up to be effective and too low down also; http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_8_par022.htm

http://www.finehomebuilding.com/how-to/qa/removing-collar-ties.aspx

Check your rafters, and ceiling joists from span tables, AND notice the drawing (bottom page) of "Purlins" and struts (braces)--- which would help support the snow load at mid span on the bearing walls below and give you storage room in center (with best headroom) to boot; http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_8_par027.htm Or, just re-install them in the upper one-third where they should be to be effective, not at existing area.

Gary