[Elecraft] OT - anyone have experience with effects of metal roofs on antenna performace?

[Mike Harris]

I run an Optibeam OB9-5 at about 42 feet on a tower only 10 feet away 
from the corner of our single story house with metal roof.

It hasn't disadvantaged me any.  I see a small change in SWR as the 
larger elements of 20M and 17M swing over the roof.

Regards,

Mike VP8NO