Concrete – Alternatives to bituminous membranes for concrete roof

This new question is related to this old question I had previously asked, but from another point-of-view.

I have a 13ft x 13ft rooftop made from plain concrete. It's leaking a bit, so I have to do something about it. I was going to do it on my own, but decided to hire a professional… for now.

I called several contractors, and they all work with bituminous (or asphalt) membrane rolls that are installed with a torch. I asked a few of them if they can apply a product applied with a roller, but they make a point of telling me that they only work with asphalt membranes. Unfortunately, the estimates are very high.

So these is what they will do:

1. wash roof with power washer
2. Apply primer with roller
3. Apply bituminous/asphalt membrane rolls with torch

Few people (if any) walk through this 13'x13' area, so I'm not sure if this membrane is overkill.

I guess my question is, is there anything as "thick" as the membrane that can be rolled on and that may also cover up any defects in the concrete?

I really like the idea of this membrane, because it's almost like a "carpet" that will cover the concrete and any ugly details the the floor may have. On the downside, this product is quite expensive and the labor is ever more expensive.

Btw, we live in the Caribbean and it cannot be the reflective white that hurts your eyes when looked at directly. Also, I don't mind the surface getting warmer.