Yes, uplift is the wind lifting the roof off an open structure.

When the post tenon is cut for a corner post to plate connection normally we don't make it a full width tenon, because if we did it could come right out to the end of the plate. So it is cut back usually 2" from the surface of the post that would be the gable end of the building.

As shown here:



In the above exploded drawing, I have moved the plate up and rotated it so that we could see the tenon and the mortise in the bottom of the plate.

I set the top of the tie to be flush with the bottom of the plate before the housing was cut into the bottom of the plate.

And I followed the same rule that the tenon on the tie beam should be cut back as it is within 2" of the end of the post.

I moved the tie beam back so we could see the tenon. This tenon is now 6" tall instead of a full 8" tenon.

This will allow 2" of relish above the tie beam mortise in the post before the tenon on the post to connect to the plate.

All tenons and mortises are 2" off the face and then 2" thick.

With the post top tenon into the plate 6" it would be hard for the post to split much if the tenon was tight to it's mortise.

But if it did split you could put some fasteners into the post above the tie beam mortise to hold it together. And cover these with some peg ends so that they don't show.



Just my ideas on the subject.

Jim Rogers

Wow! Thanks Jim. Great information and thanks for the diagrams.

Thanks Timbeal. Your information is appreciated.

Jim are you finding this joint is working? The basic structure of the building I'm working on now was not designed in shop and he have had to go to lengths of using splines to keep as much meat in the post as possible in similar cases. In your example we would put a 3-4"x1 1/2 spline in the bottom of the lower beam.

I'll have to go to an existing shed that we put together last September to see if his posts split or not.
When I do I'll take some pictures.

Jim Rogers

Hi;

Sorry my link did not work...it still works for me. I had to go to the source to find an illustration...The Netherlands. I hope you can read Dutch! Not really. You can see the illustration which shows a head beam bent (kopbalkgebinte). While on this site check out the other bent types (gebinten)

http://www.restauratieambacht.be/index.p...&Itemid=451

Jim

Hello,

Kopbalkgebint = head beam bent - (kop, balk, (ge)bint).

Greetings,

Don Wagstaff

I assumed the split was going to be from the top of the through mortise of the top of the post. That's why I suggested fasteners to the side of the post that I did.

Then I was referred to the drawing on page 88 in Jack Sobon's book which shows the split 90° to my assumption.

I now see why there could be pressure there that could split the top of the post.

I has been recommended to me, that the distance from the top of the tie beam to the top of the post should be at least 8". So, I thought I'd pass that on.

To help prevent the post from splitting due to the force of the rafters pushing the plate out, you could put a metal strap on top of the tie beam through the through mortise and up the outside of the post.

Something like this:



However you have said:

Common rafters will be used with a ridge beam. The ridge beam will be supported at each end with a small " queen post" above the tie beam.

Which to me means there will be less thrust force at the plate due to the fact that the common rafters are secured to the ridge beam, than if there was no supported ridge.

Jim Rogers