Timber Framers Guild Forums Tools Timberframe Design Interrupted or continuous top plate

I am finalizing some plans for a 21' x 32' frame and am undecided about the top plate (principal rafter/purlin roof). I could go with a continuous plate if I scarf it together. If I use an interrupted plate, I am concerned that my plate-to-post joint will be weak since the tenons will have to be so short (3"). I have seen a number of plans with short tenons at this joint but the amount of relish after pegging just seems so small. Does anyone have any recommendations from design, cutting and raising perspectives?

Thanks and have a happy Christmas.

I am no expert and am usually (well... always) on the receiving end of Q&A's on these forums. But I'd like to direct you to Jack Sobon's assesment of the framing scheme that you question. On pg.72 of the Guild's red book, Timber Frame Joinery and Design Workbook, Jack writes about this modern framing technique. And it ain't pretty. And I could also direct you to Ted Benson's and Chappell's books and the large number of frames being built today that leave out the continuous top plate and stand tall and proud. I suppose there are pro's and con's to each style. Not trying to start a war, just trying to help out. Ron

One way to solve this situation is to use spline joinery. It eliminates the tenons and eliminates the tension at the post.I believe it lso makes for safer and easier raising. General gist is a loose spline through post and pegged to plates both sides of post.

We use a spline for that joint often. Works great.
The top plate is housed 3/4", the 1 1/2" x 5" hardwood spline extends 12"into each plate (from post face). Gable ends have a spline also. During the raising the bents only have to spread the 1 1/2" max for the girt to drop on. Safe, simple, and stronger then short tenons. Sometimes the spline is flush on the bottom, sometimes proud by 3/4" with each end beveled up.

Thanks Ron, Mike and 345 for the advice. I have decided to use 1 1/2" x 6" splines at the top and wall plates and have found some good support for this approach in the Red Book.