Ayers, how could you not expect a climber not to pounce when rope is under discussion....

Rope, like so many things we discuss, comes in many different sizes and types. It all depends on what you want to do.

About the only climbing use for paracord, even the real stuff, is for shoelaces. In the early 60s, there was a minor fad in the climbing community involving the use of paracord for rappel anchors. Even tripled or quadrupled, several people died. Rappel anchors don't have to be that strong, either.

8mm cord could be just fine, if used properly. One important point - ropes often fail, not because of overloading, but from abrasion. It is amazing how fast a rope can abrade, especially under load (as when your bod is haning from it as you rappel). One jerky, poorly performed rappel can slice a rope much thicker than 8mm. So padding the rope, as you exit your building, is super critical - not just the lip, but very likely any point where the rock touches the building.

Don't even think about Spectra (previous post). It is strong but it has virtually zero elasticity. This is a critical attribute for climbing purposes. I don't think I would want to try to handle something as thin as mason's twine in any climbing situation I can think of.

I would agree with you, thicker rope is better than thinner unless weight and bulk is really critical. Some cavers, I understand, are dropping on 7mm rope, but they treat it right.

How far do you have to rappel from your office to reach the ground? FWIW, it seemed to me from SAR experience that groundfalls of more than forty feet (four stories) were generally fatal, while shorter drops were typically survivable, unless you impacted very badly.

Climbing has a lot more to it than just getting a rope, especially if you want to survive.