Building a Goat Barn #10: Testing Out the Reciprocal Frame Rafters

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Blog entry by David Bareford posted 08-04-2014 01:34 PM 2874 reads 0 times favorited 6 comments Add to Favorites Watch
« Part 9: Attached Chicken Coop Part 10 of Building a Goat Barn series Part 11: Starting on the Paddock Fence »

Inspired by Simon Dale's Low Impact Woodland Home, the roof for the barn will be held up by reciprocal frame rafters rather than a ridge peak or a truss system. This will allow a clear span beneath without support poles. Other web resources about this kind of roof can be found at the Year of Mud blog and at Green Building Elements.

This weekend, I tested out the reciprocal frame concept on the ground ust to make sure the voodoo works before I tried it ten feet in the air. First, I brought the rafters together in my driveway:

For the curious, he poles are 14’ spars of either red alder or bigleaf maple, debarked, with base diameters ranging from 5” to 7”. The next step was to put the first rafter on a “charlie,” or a temporary support, then beginning laying the other rafters one by one. Each rafter pointed 18” to the left of center, to produce a 36” central circle. After all eight rafters were placed, I carefully knocked the charlie out from the under the structure, to find:

It worked! Without fasteners of any kind, the rafters were supporting themselves off the ground by about two feet! I even climbed up on the top and bounced up and down. The more pressure I exerted, the stiffer the frame got. Very cool. Here’s a look down at the central circle:

This Saturday, we put the frame in the air…

6 comments so far

View lightweightladylefty's profile


3266 posts in 3913 days

#1 posted 08-05-2014 04:41 AM


You’re certainly teaching us all kinds of new stuff. (We’re too old to put it to use, but it’s certainly fun learning!)


-- Jesus is the ONLY reason for ANY season.

View Jake's profile


850 posts in 1831 days

#2 posted 08-05-2014 07:33 AM

That is awesome! Definitely going on my bucket list for when I buy my own property in the middle of the woods.

-- Measure twice, cut once, cut again for good measure.

View firefighterontheside's profile


19432 posts in 2057 days

#3 posted 08-05-2014 11:55 AM

That is cool. I’ve got lots of eastern red cedar I could do that with. Maybe my next goat barn.

-- Bill M. "People change, walnut doesn't" by Gene.

View Ocelot's profile


2113 posts in 2838 days

#4 posted 08-05-2014 12:01 PM

I like stuff like that!

I would, personally, want to tie some wire or something around the places where the rafters meet, to (try to) insure that they don’t slip.

... but cool!


View David Bareford's profile

David Bareford

66 posts in 1807 days

#5 posted 08-05-2014 01:00 PM


I definitely plan to secure the rafters when I put them on the barn. First, where the rafters rest on the post, a vertical pin of 1/2” rebar connects the rafter, the two half laps of the horizontal beams and is driven over 12” down into the post. As I lay up the rafters, I will start by hammering in a 6” nail in the supporting rafter to prevent the top rafter from slipping down, then I will lash the rafter in place for extra security. Once all the rafters are laid up, the support is knocked away, and the roof finds its final pitch, I’ll peg each rafter to the one below with a 1/2’ diameter hardwood peg, and I’ll likely add some nail tape around them as well. I believe in physics and geometry, but when I add a ton of dirt overhead for the liviing roof, I want to very sure it won’t come down around my ears!

View Tim's profile


3812 posts in 2162 days

#6 posted 08-08-2014 05:46 PM

That is really cool. Ditto what Jake said.

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