In this video what I want to show you is the positions of the members and
The bevels required to construct a semi octagonal roof
Which is probably the most common type of octagonal roof, built if you wanted to build a fully
Octagonal or an eight-sided roof then you can just mirror
What I'm about to show you and I'll show the other main difference as we get to it
So here's our roof with our semi octagonal
end
As you can see there and here are the centreline positions of our main members so our
Centering rafters will go here
our
rafters run at 90 degrees to our plates
So we're gonna have a few more rafters of different types of rafters that we had before
our hips bisect our corners
And our corners this time are not 90 degrees, they're gonna be 45 degree corners here
and we of course are gonna have creepers
And we're gonna have common rafters hang out the rest of the roof as well
So you notice that the distance that we have here is
equal to the distance
To our centering rafters, and I'll explain in another video. How we get this distance and
how we work out these wall lengths as well
So as usual our first two members are our ridge and
our centering rafters
and if you're doing a fully octagonal roof you would not need to have the ridge you were just but
the two centring rafters together they were meet in the middle and
Then you can just
Mirror what we're going to do on this side on this side to create a fully octagonal roof
So ridge
centering rafters a
Crown end rafter coming in at 90 degrees to a centering rafters
Now a little bit of difference we have these two rafters here now even though they look like hips and they're gonna have
The old hip bevels on them
They are actually rafters because they're coming off the plate at 90 degrees
Okay, but they're going to have an edge bevel on them
So that's the one bevel that's different to a hip roof that we need to develop
and
Then we're gonna have our hips
Bisecting our corners and coming in as well so quite a bit of timber sitting up here at the gathering point
And gets you know fairly complicated sitting in there
And then we're gonna have our creepers coming in 90degrees of their plate to our hips and
Of course we'll fill the rest of the roof in with common rafters, and do whatever
Roof you're doing on this end or whatever system you're going to do here
So there we go we also need to put in our ceiling frame of course and our underpurlin and if the rafter size
dictates that we need it and that's our
semi octagonal roof put together
So the bevels that we need as I said before pretty similar to our
standard hipped roof except if we have an extra edge bevel for our rafter so
first one there plumb bevel for our common rafter
Of course we're gonna have a level bevel for a common rafter
We're gonna have an edge bevel for our creepers and
An edge bevel
for our rafter
Okay, see they want to mix them up edge bevel creeper down here edge bevel rafter up here
We're gonna have our standard hip bevels. It's a plumb bevel hip
Level bevel hip
And our edge bevel for a hip
And
Then we go around our purlins bevels, it's a face bevel purlin
Edge bevel to the Pelin
And that's it nine bevels to create a semi octagonal roof