A well designed and executed low slope roof does not leak. They are designed to handle hydrostatic pressure, ice buildup etc. Penetrations must be high enough to handle anticipated snow loads. If you don't have internal roof drains you need them. Internals stay warm and allow melt water to exit the roof.
All roofs leak eventually. I had a client once that was complaining vociferously about his flat roof that was leaking. He was right, but it was the base flashings that were leaking, not the roof. It was a 45 year old 5 ply Coal Tar Pitch built up roof with Tar Based organic felts. Counter flashings were 22 oz. lead coated copper. That roof was literally bullet proof. God is in the details.
Oh Sorry, Heat tape will do nothing for you, you need to have your roof redesigned by somebody like...........................ME.
" A lot of men build things, and a lot of things fall down "
Last edited by jagans; 01-08-2013 at 10:06 PM.