Hi, I'm new to construction but am trying to build a timber framed garage. I have 6x6 posts and 6x10 beams which I need to join over the posts. I was thinking a lap joint. What is the easiest joint to make over the post and what length should each lap be? Should the joint be directly over the post or should it carry over beyond the post? Any diagram or photo would greatly help. Thank you.

Hi Cory

Have a look at the following in Part Six Scarfs for an overview on a variety of scarfs, their relative merits and locations.

http://www.tfguild.org/joinery/joinery.html

Thank you. I have a timber framing book by Jack Sobon which has been very helpful. I guess I'm not trying to actually splice a beam but rather join two beams over a post and am looking for the easiest way to do it. I was going to do a lap joint in the beams over each post. I was looking for a diagram or measuremnent of where the joint placement should be. I know I should have each beam resting on the post but how many inches of beam should be supported by the post? If I just butted them up together I would have 3" of each beam on a post. With a lap joint how big should the laps be? Should each lap be 3"? I hope this isn't written to be too confusing?

Cory,

This is what we are doing at an upcoming TFG workshop.
Whatever solution you choose, you need to make sure it works for your design loads, brace locations, etc. If you have any questions you should find an engineer or local timber framer to guide you through the process.







-Mike

Cory:
You need to understand the load being put on the beams. And that when you cut a lap you are cutting away half the beam where you need it to be the strongest. This is not good.

Read Jack's book again and make a scarf off to the side of the post not directly over it.

The scarf can be/maybe a simple half lap, if there is no tension in the beams.

As mentioned have an engineer or someone else look over the entire design to make sure you doing something safe.

Jim Rogers

The expression "quarter-point" comes to mind on this issue.
Carpenters often make joints in a built-up beam assembly one quarter of the distance between supporting points because this is where deflection and shear are typically "minimal" or greatly reduced from the measurements found at the supporting points themselves.

I've quarter pointed many beams, but they always have another ply spanning the full span of the beam section with the quarter pointed ply supported by one end and at least running past one post. With the entire beam spliced, it would be logical yet unnerving (no supporting plys) to set the splice at quarterpoint, perhaps with the longer canterevered beam section joined so it rides on top of the shorter cantilevered beam. I agree with the concern of reducing the beams depths at the post where all the shear is. With a joint over the post, may as well butt joint it for full bearing with a top spline to tie. Not as sexy a joint though. Any engineers have a general opinion for a rule of thumb?