The Forestry Forum

General Forestry => Timber Framing/Log construction => Topic started by: future_vision on January 16, 2023, 01:39:51 PM

Title: Timber Frame Design for a Modern Shed Roof Barn 24x36
Post by: future_vision on January 16, 2023, 01:39:51 PM
Trying to figure out the best way to pull off a timber frame barn that has a shed roof at a fairly low pitch. Maybe around 2/12. It would be 24' wide and at least 26' deep. New England so a decent snow load. Preferable no center posts but could probably do  some offset. Probabaly around 8ft  from either side wall. Possible? Thoughts on how you would approach it?
Title: Re: Timber Frame Design for a Modern Shed Roof Barn 24x36
Post by: DangleSnipe267 on January 17, 2023, 09:13:08 AM
It comes down to what you are willing to do to achieve this. Technically it is "possible" but it isn't very practical. For starters, you will need something on the order of 30' long rafters (due to roof pitch). Are you able to acquire / saw that out?

Assuming a snow load of 50 psf, you can maybe get away with 6X10 spaced 24 O.C. if you don't care that it deflects over an inch. If you care about the deflection you probably need something more like a 6X12. Maybe you can get away with engineered joists for that load / span. Sounds to me like you want a steel building. You could probably build a hybrid and just use steel for the joists.


Offset posts and associated plates (from center) will reduce the rafter length and therefore size / deflection.

-Tim
Title: Re: Timber Frame Design for a Modern Shed Roof Barn 24x36
Post by: future_vision on February 03, 2023, 05:27:49 PM
I was thinking that the rafters would be in at least two pieces with maybe some type of scarf joint and there would be some type of truss magic going on.
Title: Re: Timber Frame Design for a Modern Shed Roof Barn 24x36
Post by: Mainecoast on February 06, 2023, 12:58:27 PM
I would try for a bit steeper pitch. 

Most metal roofing I've dealt with isn't even recommended/warranted at anything less than 3/12
Title: Re: Timber Frame Design for a Modern Shed Roof Barn 24x36
Post by: Prizl tha Chizl on February 07, 2023, 04:59:28 AM
I posted a 25x26 design I'm building, (with a few modifications) for a friend in the plans section. I would do your own math on the loads or ask here for design help if you're planning on using any version of it, I'm unabashedly an amateur. 
I agree, flat and low pitch roofs are not ideal, I'd rather see something that would shed snow and ice, but these folks not only wanted to match their house roof slope, but also were worried about blocking  their view. This one will have a 24 gauge standing seam roof, which can handle it. I couldn't see my way around a center post, someone smarter than me might have ideas, though. It could probably be moved a few feet one way or the other if you pay  attention to how that affects the load.