Here I am almost done with all the timber
framing and am in the process of cutting the
6"X8" floor joists and installing them.
As it can be seen, I have installed all the
top plates and some of the corner rafters
for the half- octagon shaped front living
room.  The top plates sitting on ¼ thick
steel plates  are reinforced with 1" nuts
and bolts to each other and the support
The rafters were ordered
from a nearby sawmill and
were pulled up to the second
floor in bundles using the
timber frame and pulleys.  
The 2"x7" rafters were
necessary because I had
planed to install R-19
insulation on the roof and to
have enough ventilation
space for air flow between
the insulation and the back
of the decking.
Rough-cut lumber varies in dimension and
require adjustments being made to them in
order for the roof to be functional.   One way
to do this is to make a template out of your
first rafter after it has been cut and fitted
correctly on the ridgepole.  Use this template to
cut rest of the rafters by matching the top of
the rafters with the top of the template.  Again,
the bow always goes on the top.  The
disadvantage to this process is that if you plan
on using the bottom of your rafters as a ceiling,
then additional adjustments are necessary since
these bottom raters will be uneven.  The
second choice is to determine how many
rafters you need for a ceiling, use the rafter
with the smallest width as a template and plane
or cut the rest to size.
Here the plywood
decking was being
nailed to the rafters.