23.625

arrived at that figure by dividing 30 by 9.5 and getting about 3.15
then divided 19 by 6 and got about 3.15
then multiplied 7.5 times 3.15

s

"jtpr" wrote in message
...
On Sep 30, 10:00 am, "Steve Barker DLT"
wrote:
No, you are correct. 7.5 inches is greater than 6.

steve

You still can't load the bottom chord of a truss however. Are they
trusses,
or conventional rafters and ceiling joists with support poles?

"jtpr" wrote in message

...

I'm missing the math, but this is a garage with 2x8 rafters spanning
19'. I will be putting R30 (9.5") up there and if I do put some
plywood on top for a little storage it will compress it to 7.5". So
it sounds like even with the compression I'm better off then the
alternative of R19.

Am I off base?

-Jim

They are conventional rafters and ceiling joists, 16" OC 19' span. I
know I'm being thick, but given my example of compressing R30 by 2.5",
what do I end up with?

-Jim