Post to Principal Rafter

This joint has become one of my favorite ways to join a principal rafter to a post.  It offers a clean look and allows a plate to join to the post with a spline and a tie beam that can handle sustained tension.  A basic mortise and tenon in the rafter and post with a diminished housing allows the tenon and rafter to bear directly on the post and then the through-bolted tie beam resists any outward thrust of the roof.  

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2 thoughts on “Post to Principal Rafter”

  1. Would it be more realistic to use a Double Mortise and Tenon Joint and add the plate and spline a little lower down to tie queen trusses together? Thanks for the awesome website. The information you are providing is really invaluable!

  2. Katrina Williams

    This detail is just a single solution to a complicated situation where you have all the components coming together in this configuration. Typically a double mortise and tenon joint would be fine and the plate and spline could be lower but the spline is catching the decking for a principal purlin system, so it needed to be high up and beveled into the spot. Tie beam placement was lower, not sure of the reason. The tension on the tie beam was high so the bolt and plate were added by the engineer.

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