Replacing Flat Roof Over Garage

I had some storm damage that put a few holes in a flat roof over an attached Garage. The Garage Joins a sloped roof as well as a family room addition with a flat roof that is several inches higher than the garage. The garage was a converted carport and from what I can tell has zero slope and has some serious ponding problems. It was repaired before I moved in about 5 years ago and now I want to replace the whole thing. It has Roll Roofing on it now, which is what the insurance will pay to replace. I am concerned that there is no drainage and what seems to be a tendency to collect water in the center. I have had several pros look at it and have had some say they would just replace the rolled roof, others suggest putting foam over the whole garage and family room area, others suggest a built up flat roof. It seems to me that something should be done to provide proper drainage, but I’m not sure what is the best way to go. Another consideration is that I am in Phoenix, so it will be exposed to a lot of high temperatures as well as pounding rain and high wind during the monsoon season. Thanks in advance for any advice.

I’m from Australia and am not sure if it is available over there, but Insultec heat reflective & protective coating might be beneficial. It can be applied on metal roofs (such as garages).

Might be beneficial to do a search for it on the web to find out more.

Tear it off and build it back up using tapered insulation, or possibly restructing the joist and rafter system to facilitate better drainage. Put down a quality membrane that can withstand some minor ponding, but before you do any of that allow a compitent roofer to do it for you since I do not feel roofing is a do it yourself thing.

ditto grumpy - old man thumbnail icon.


apply a new rubber membrane,using tapered iso poly,also you might want to install some scuppers to pitch the water to,with the iso.