On Jul 14, 4:55 am, "DanG" wrote:
I would use a 4 foot level and divide the resultant total rise by
4. This method gives an average rather than concentrating on very
small section. Cut a few scrap blocks at 3:12, 3.5:12, 4:12 and
test fit.

You describe a typical cut roof with collar ties. Very normal,
very strong, and still built every day. Trusses are just an
alternate system. There are times when one is more appropriate
than the other. They each have their strengths and weaknesses.

The rafters have nothing to do with the ceiling structure as far
as hanging a punching bag. The ceiling joists form the bottom
structural chord of the rafter triangle and function in tension to
keep the outside bearing walls from spreading. If you are having
some kind of problem hanging the punching bag, then ask about
that, not about the roof rafters. The roof rafters should not be
involved in a ceiling hung load.
--
______________________________
Keep the whole world singing . . . .
DanG (remove the sevens)


"Eigenvector" wrote in message

news


Are roof angles necessarily standard? I ask because I'm going
to be working on the rafters and need to cut an angle piece to
fit in beside the 2x8 holding up the roof.

I measured it out and came out with 9 inches over, 2.5 inches up
which should equal ~15.5 degrees for the roof angle. I'm not
interested in perfection, it just has to fit reasonably, but if
I can get it exact it sure would be nice. However 15.5 deg
doesn't match a 3 in 12 or 4 in 12 pitch more like 3.5 in 12.
That's why I'm asking if roof angles are standard, or at least
WERE standard in the 1960's.

Just for clarification, my attic is ridgepole construction, 2x8
supports for the roof, every other truss has a 1/2 x 10 board
connecting the 2x8 supports. Weird construction, doesn't look
sturdy at all in my eyes.- Hide quoted text -

- Show quoted text -

The simple, fast, and very cheap, method is to use a friggin bevel
guage. It will let you lay out the exact angle in a few seconds and
there is no figuring or measuring (other than for length) involved.
You don't even need to know what the rise/run, or angle, is.

I am surprised at all the people who think you need to do all that
leveling, measureing, figuring. A bevel gauge should be one of the
added to a DIY kit at a very early stage.

Harry K