Oak Walkway Modified Jowl Joint

The 25m long walkway followed a curve on plan and with its mono pitched cedar shingled roof  it created a complicated junction with four large timbers all at different angles meeting at the same point, these where the post, two angled wall plates and principle rafter. Braces where needed in three directions so three plains needed setting out.

For this we developed a more complex version of the traditional jowl post. It was complicated to make and difficult to draft and finish in each plain. We first made a scale model of the junction and then had full scale templates of each part to test them all fitting together.  Eight years on and it seems to be doing fine. However, retrospectively I wonder if a steel node with flitch plates for each timber might have been a more straight forward and quicker to make solution.

See the attached images of the exploded scale model, and full scale version for more detail.

Jowl Posts was traditionally used at the top of the main posts which where flared at the point of intersection with the wall plate and the tie beam to the create the “English Tying Joint”, an ingenious medieval joint that holds the truss onto the main frame and stops the frame spreading outwards under upper story or roof loads, dealing with timber in a tension joint. We have more recently used dovetailed wedged tenons to do a similar job. The flared top of the jowl post would traditionally have been the main stem of a tree turned upside down,; using the natural curved grain of the timber as it flares out at the bottom of the tree just above ground level for the jowl. Again see examples of a scale model of this joint.