I am putting in a bathroom in my basement and know I need to vent the
fan. I plan on running the vent between the joists, but I'll need to
jog around the i-beam. is it okay to use flexible dryer-vent type
pipe to come down and then back up to get around the structural beam?
Essentially it would look lik ~~~~U~~~~~~ where the U is the flexible
vent pipe going underneath the beam? Other suggestions?

Thanks,