Expert: Bruce E. Johnson - 8/30/2008

Question
Hi Bruce, I am in the process of designing a 14x26' garage and wish to mimic the hip roof design on my house. Is it more or less expensive to have trusses designed for the roof or would traditional rafter framing be more economical? I have never had trusses designed so I have no idea of their cost versus traditional framing. Any advice you could give on this would be greatly appreciated. Thanks in advance...

Answer
Hi Daniel, trusses are overall generally less expensive than conventionally framed roofs for the following reasons:  
A conventional rafter framed roof requires much larger, more expensive, material.  Most rafters will need to be at least 2x6 and in a lot of cases 2x8 in order to support the weight and cover the span requirements.  Trusses, on the other hand, are made of 2x4 usually and are engineered to utilize the maximum effectiveness of the smaller wood to make the roof system as sturdy or sturdier than a framed roof plus provide and interior ceiling capable of holding a certain amount of weight such as garage door openers and drywall.

A conventionally framed roof requires more advanced carpentry skills and significantly more time to install than trusses.  If you have the time and the skills then that is one factor in your favor. But if you are paying someone by the hour or are pressed for time a truss system will take less than half the installation time as a framed roof.

A trussed roof, as you mentioned, is engineered using the latest techniques to design a roof system to meet your needs.  A framed roof, unless you have a roof framing book that specifies the proper rafter sizes etc., it is pretty much your guess as to what size materials to use for your type of roof.

I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com