Time to get a new roof. I have a commercial bldg, about 7000 sf. It if stupidly flat. Of course, with flat roofs around here, there are low spots- that form puddles/pools. I heard that now the codes have been demanding roofers flatten out these low spots so water shes off much quicker (not sure how they accomplish that).
BUT, The roof that was put on in 96 is shot- lasted a dissapointing 16 years. Whats the best roof to put on there now? I heard tar and gravel is time tested. Others use overlapping membrane. (currently, I have multi layered/"feathered" fiberglass with hot tar in between layers. Sounds impressive, but didnt last for beans.
Alexander Pope: [a little knowledge can be a dangerous thing]
First you need to know if it's low sloped, flat or dead flat, depending on which one it actually is plays a large roll in the system you decide on.
Looking at the roof shortly after a good rain fall will show exactly where puddling is happening and give you a good idea of how well your current drains are functioning, which will also play a part in which system to choose.