The Forestry Forum
General Forestry => Timber Framing/Log construction => Topic started by: LimestoneWood on July 13, 2017, 03:21:20 PM
Hello Everyone,
My name is Andrew and I'm new to the forum. I have been working on a timber frame design for an 18x18 shed. I have run into a problem joining the tie beams to the center post. The post is 8x8 and I would like to inset the 8x12 tie beam by 1 inch into the center post along with a 4" long 2" wide tenon. But that sets the tenon 5" into an 8" post and I have to fit another tie beam into the same place on the other side. Should I simply make the post 12" wide or should I go for an over-under tenon? Or is there something else that I should do?
(https://forestryforum.com/gallery/albums/userpics/46429/20x20_timber_frame.jpg)
Please remember that this is my very first timber frame and I am not looking into getting into very complicated joinery. That is why I am using a post in the middle in the first place. However, I am a woodworker by hobby so I'm not completely lost.
Any help that you can offer is greatly appreciated.
Thanks,
Andrew
Widening the post could work. A free tenon would be the modern answer to your dilemma. It would run through the post, and go maybe 12-16" into each beam.
The beam splitting the center post is more of a problem. It's a hinge point. You'll also have a lot of cross grain shrinkage. Even without that middle beam, you should leave a gap between the rafters. So that when the ridge beam shinks, they'll still bear on the beam.
Lose the lengthwise center beam under the ridge, run the ties continuous and tennon posts under and over the ties, brace upper posts to ridgebeam?
Hi,
Okay, so if I understand this correctly the center beam/plate should be removed. I assume the posts underneath it would become taller and go all the way up to the very top plate/beam. The tie beams meeting in the center post could then receive the floating tenons.
I would still have nine posts but the center ones would be taller. But now I would only have three beams/plates instead for four.
As far as the rafters go, I don't understand the solution. I understand wood shrinkage and now see the problem that has been posed but can't visualize how to fix it.
Thanks for all your help! I'll get a new design posted within the week to clarify the wording.
Thanks again,
Andrew
Oh never mind on the rafters. I get it now! Duh:)