On Sun, 05 Jul 2015 17:51:00 +0000, David wrote:

So we tied the wall plate (wood along the top of the wall on which the
rafters rest) to the wall with straps.

That makes sense.

[From your photographs I thing the wood you are calling a lintel is
actually a wall plate.]

Probably. But a bloody great big heavy one...

From your pictures I couldn't see any sign that the wall plate was tied
to the wall.

No, it seems to be that nice Mr Isaac Newton alone who's keeping it there.