We have a winner!Mathieu wrote:A couple of days ago when looking at his blog I noticed immediately that there is a pocket for a jack rafter tenon at the keta level in the hip rafter. Either this pocket should not be there, one too many or I have no idea how he will attach the jack to the keta AND into the hip.
I guess this anomaly is not what we are looking for? But I am still pondering about this one too.
Yes, the mortise for the jack rafter tenon directly on the keta centerline should not be there.
Here's another photo to show the area more clearly, problem mortise indicated with a red circle:
The jack rafter aligns to the centerline of the keta. There are three solutions to framing that:
- 1) cut a shallow pocket on the end the keta nose and attach the plumb-cut rafter there
2) cut a trench along the sloped nose of the keta and a mortise pocket in the hip. The rafter passes intact through and up the keta end and into the hip
3) combine pocket and hip rafter mortise, but only trench the sloping nose of the keta about half-way deep. The jack rafter is similarly cut.
In the case of the above-shown framing at the hip, the presence of pillow blocks below means the keta-bana is much longer than it normally would be. This may have thrown the person off doing the layout, though I find that surprising since they use CAD for their layout. If the keta-bana had a half-depth trench in it for the jack, that would be one thing, however the way it is framed the jack is clearly mean to terminate in a notch on the nose. so, the mortise on the hip aligned to the keta centerline is superfluous.
Possibly they intend to fill in with a little piece of wood there to present the simulation of the jack continuing up into the hip, but if that is the plan I see no necessity for the mortise in the hip.
I think that laying out and cutting that mortise in the hip would be a very easy mistake to make. Luckily, when the decorative eave ceiling boards are all in place, it would be very difficult to spot from the ground.