From my understanding you create a material push the smoothness to 1 and then place a reflection probe in the scene and all the materials smooth enough.
Floor reflection unity.
I like this opencv asset for unity.
I suspect that this will be the hardest part of what you need to accomplish.
There are two buttons at the top of the reflection probe inspector a unity window that displays information about the currently selected gameobject asset or project settings alowing you to inspect and edit the values.
This approach is very hacky but you can use the new reflection probes in unity 5 to easily create realtime reflections for something like a reflective floor.
More likely you d use a camera in the ceiling and probably want to process it with opencv.
You can probably use this for more things like wall mirrors and multiple reflections in the same scene but that would require quite a bit more scripting magic.
With the leftmost button size selected.
Here s a quick tutorial on how to create realtime reflections in unity 5.
Screen space reflection is a technique for reusing screen space data to calculate reflections.
More info see in glossary window that are used for editing the size and probe origin properties directly within the scene.
It is commonly used to create more subtle reflections such as on wet floor surfaces or in puddles.
Now i did realize that unity free has reflection probes.