also you did not say anything about snow loads in addition to the dome.

"Bob G." wrote in message
...
I have a 24x24 foot building (barn roof) in my backyard which serves
as a garage...

I am into astronomy and because of trees etc the only good place to
"construct" an dome shaped observatory is to place it on top of the
barn...

The weight of the Fiber glass dome with a 6 foot 6 inch headroom in
the center is only 350 pounds (the walls dome itself)... which leads
me to think that I really could build a 8x8 platform on top of the
existing roof and erect the fiberglass dome...

Existing rafters are 2x6;s spaced 24 inches on center gable shaped .
I would not be removing any...just cutting a hole in the roof under
the dome so I can climb up a ladder to enter...

Seems to me that adding 350 pounds PLUS "me" and the Telescope and the
laptop on the roof would be possible..

What I do not know yet is how to mount a pier up there so that it
would be stable enough to hold the telescope stable ... First things
first... can the existing roof hold the weight....?


Bob G..