We have a roof problem that could most easily be solved by doing
somethign that would lower the pitch from 4:12 to 3:12. I keep hearing
that 4:12 is the "minimum" pitch for a shingled roof. But, that's also
what it was in the Stone Age.

I wonder if that rule still applies, if I underlaid the whole thing with
a bituminous membrane (aka "ice and water shield")?

Thanks,
George