Re: Extending 6x6 support post

Some last minute thoughts

Imagine that instead of a pagoda you were to set a well made table on these existing posts.  There would be no levering force on the new post joint because the legs of the table are fixed to the table skirt.  The legs can not apply any levering force to the bottom of the leg because they can not move in this direction, they can only slide.  Resisting sliding is times less force than resisting levering with that long extension post.  Carrying this thought forward......

Presuming it is unattractive to brace the post above the joint, next best is to brace it at the top of the pagoda.  Make the roof of the pagoda the equivalent of table legs mortise and tenoned into table rails.  If the legs can not lever against the joint bolts the requirements of the joint can easily be met with the half lap proposed.   

My solution

I decided, with the approval of my wife, that I will sink two new post in front of the existing post.  That way it will be supported all the way to the ground with one piece of lumber.  Thanks for the replys and helping me figure this out.