Some finer details
I’m still a little too busy to be typing this, however I think it is important to clarify the difference between a carefully thought out hand cut frame and something spewed out by a machine. I have some words on this here: http://www.chaplinoak.co.uk/britishscribe/
Here is the frame I am currently building; a simple extension over two floors.
Though this current frame is fairly simple, it is based on a well proved 1 ½ storey design, there are some subtle details that distinguish it as unique.
The collars in the trusses are not curved, but tapered, being deeper in section in the middle. This makes for a tidier design for the open trusses within the bedroom space. Here we have the central truss pinned together in the workshop.
I think these would have looked nicer if accompanied by tapered rafters, but the structural engineers calculations had already been done!
The following picture shows the main floor beam (cross-rail) connection to the post. Given this is a clear span, with no bracing, this joint needs to be sufficient to take all the downward load of the 1st floor. This is known as a diminished housed tenon. The tenon is extra thick to help spread the load.
That’s about all for now, hope to update when this frame goes together.