Helpful? 0

Sizing timber frame roof purlins

For those of you that live in a moderate snowy area such as Pennsylvania or New York and have a Timber Frame roof system of bents and purlins with t&g on top of purlins. Question is with bents on 16' centers what size purlins do you have? I imagine to satisfy the code it would be considered rafters with ceiling attached which would fall under the 240 deflection rule. For purlins on 48" centers, 15' length at 30psf (1800 lbs) a 5X7 would have .799 deflection, a bit above the allowable .75. This is telling me it would require a 6X8. Make sense? What size bents do you have holding up your purlins?

Asked by John H. Stehman
Posted Sun, 02/23/2014 - 12:57
Edited Mon, 02/24/2014 - 06:40


1 Answer

Select your preferred way to display the comments and click "Save settings" to activate your changes.
Helpful? 0

This type of question needs to be answered by an engineer.

If you are ordering your timber frame from a timber-frame company, the company should have an engineer on staff. If you are designing and building your own timber-frame house, it's time to hire an engineer.

Answered by Martin Holladay, GBA Advisor
Posted Mon, 02/24/2014 - 06:42

Other Questions in General questions

In Energy efficiency and durability | Asked by Chris Jensen | Aug 18, 14
In General questions | Asked by Tommy Detamore | Aug 19, 14
In Energy efficiency and durability | Asked by Andy Chappell-Dick | Aug 20, 14
In Mechanicals | Asked by Chris Marriner | Aug 18, 14
In Energy efficiency and durability | Asked by Lowell Garner | Aug 20, 14
Register for a free account and join the conversation

Get a free account and join the conversation!
Become a GBA PRO!