Roof was torn down and replaced in the 70's. I think it may have one or two roll out asphault roofs already on it. The roofer thinks that rubber is the way to go since it has little pitch to it.
What is Flexeril used for? Relaxes your muscles. Flexeril (cyclobenzaprine) is widely used to treat muscle spasms and is available as a generic, but it shouldn't be used long-term.
Flexeril has a half life of 18 hours. So 5x18 is 90 hours. Or just under 4 days. Of course, it is not that easy. This varies on how much and how long the drug was taken and it can vary from person to person. That being said I cannot image any way that flexeril would be detectable 30 days after the last dose.