New Flat Roof. Remove or cover current roof?

[Joe Gee]

Hello BP, 

I purchased a 4 plex recently and looking to replace the current flat roof.  The current roof is leaking in one area that the last owner patched up unsuccessfully.  The rest of the roof is holding up, but its pretty old and probably better to just put a new one on.  

My question is, do I rip off the old tar roof or just go over it with the new TPO roof.  My roofer said its better to just go over it, and if I rip it off it will cost a hell of a lot more money, not to mention open up a giant can of worms.  But if there is rotten wood underneath, I would want to deal with it now rather than cause more problems down the line.  

Has anyone dealt with a flat roof replacement?  And what do you recommend?  

I plan to keep this 4 plex in my portfolio as a long term buy and hold. 

Thanks

[Marcia Maynard]

We have a duplex with a "built up" roof with "scupper" roof drains. Although it's not flat, it has a low slope, so our options are limited. We found the best thing to do is to consult with several roofing specialists and get at least three bids. The bids can vary widely depending on the materials suggested and the skills of the installer. I generally watch a few YouTube videos on a subject before talking with contractors, especially if it's something new to me. You will find there are many new materials available these days which can surpass the tar roofs of the past. By the way, did you have the property thoroughly inspected? What did the inspection show about the current roof and drainage system? It all ties together..... roof + drainage. The drainage system includes not only how to get the water off the roof and away from the exterior walls, but also how it leads the water away from the foundation.