Another scarf joint that I have used is the “bladed timber frame scarf joint”.
This drawing is of a 6″ x 10″ bladed scarf joint that we cut to create one long timber for an addition to an existing barn.
The scarf is 2′ long and the tenons are 2 1/2″ thick and 4″ long. The joint was held together with four 1″ pegs.
7 thoughts on “Bladed Timber Frame Scarf Joint”
I bought your 12×16 ft shed plan and am expanding it to 16×20 ft so I am in need of joining two 8×8 beams to make a longer (20ft) top plate. Which is the better joint to use, this one or a spline?? I can put the joint over the bent two post (using 2 10 ft beams) or over the bent two brace (using 14 and 8 ft beams)
In your case think a scarf joint like this one is your best bet. There are other types of them out there to explore as well.
It is best to not put the scarf over a post. You are asking the 8×8 to be as strong as it can be over a post and then you cut half of it away. Not something that is usually done. Set it off to one side and support it with a brace. Use a 14′ and a 10′ so you have at least 24 of lap for the scarf. Jim Rogers
OK, a timber framer I know suggested I use a 24″ long 6×2″ oak spline through the post and use two 10 ft plates. Would that be better worse or another option?
I need to join two beams for a oak sill plate under this post also that will be supported by 8″ concrete foundation posts. Same question?
Most timbers are pine, the sill and spline if used, will be oak.
There are some standards for splines in regard to length and depths into the plates. I don’t see an option here to post another picture, so I can’t show you the “rules of thumb” I use for splines. If you email me directly I will send it to you. jrsawmill (at) verizon (dot) net. For sills that are directly supported by continuous foundations scarfs can be any place you need them to be. If it is not a continuous supporting foundation then it should be offset as well, in my opinion. Jim Rogers
Can a tie beam sit on this scarf joint safely supported by a brace. Please?
Yes, it is very common and recommended strongly by engineers.