jmme
Civil/Environmental
- Mar 9, 2011
- 25
Currently there are 5" dia. logs (18.5 feet long) spaced 36" o.c. being used as rafters for a building with a 12:12 pitch and a metal roof. The owner wants to add a sheetrock ceiling so he wants to sister a 2x to the log so he can run his furring strips and install sheetrock. Below are my calculations based on removing the logs and installing regular 2x rafters.
Ground snow load = 55 psf
Sloped Roof snow load = 17.3 psf
W = 17.3 (LL) + 10 (DL) x 3' spacing = 81.9 #/ft.
M = (81.9 x 18.5^2) / 8 = 3504 #-ft = 42,045 #-in.
This would require two 2x10's. However, the 5" logs will carry some of the load. What load can a 5" log handle?
Am I going about this the right way? Thanks.
Ground snow load = 55 psf
Sloped Roof snow load = 17.3 psf
W = 17.3 (LL) + 10 (DL) x 3' spacing = 81.9 #/ft.
M = (81.9 x 18.5^2) / 8 = 3504 #-ft = 42,045 #-in.
This would require two 2x10's. However, the 5" logs will carry some of the load. What load can a 5" log handle?
Am I going about this the right way? Thanks.
