Expert: Bruce E. Johnson - 9/23/2008

Question
We are building  home with a 12x 12 roof  pitch[ cape cod roof] Do we have to have collar ties? We prefer not to , too ,preserve the cathedral ceiling openese. We are in NY state and have to comply with the Uniform code. If so how high can we place them

Answer
Hi Al, if you have a substantial ridge beam or maybe a heavy LVL ridge board that is well supported you don't really need a collar tie with a 12/12 pitch.  You can buy steel connectors to tie the rafters together also.  If the rafters are self supporting without a ridge board then you might need to either brace your bearing walls with shear walls to keep them from bowing out or use a collar tie in the top 1/4 of the rafter.  If you use a truss system you won't need a collar tie but I'm not sure if you are going for an open rafter look or if you are finishing the ceilings with wood or drywall.  

A trick you can do if you are doing a drywall ceiling is to put in your collar ties then frame the bottom of the rafters down so that the peak of the ceiling is below the collar tie.  This way you get your vaulted ceiling plus the benefit of the collar tie.  It changes the interior pitch of the ceiling from say a 12/12 to a 10.5/12.  An engineered scissor truss accomplishes the same thing.  Consult a structural engineer or a roof truss mfg. company and either one should be able to give you a design that eliminates the need for a collar tie.  I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com