If you have a typical plywood second story and you are considering having concrete floors installed, there are a few things to consider.
First you want to make sure there are no extreme low spots in the plywood. If there are and if it is a older house you might need to reinforce the floor joist the plywood is sitting on. You probably should consider this with any other ceramic or stone floor also. The weight of concrete floors is about the same if not less then installing ceramic tile and hardi-board. So if second story in your house is qualified to accept ceramic tile on the second story you will be ok with having concrete floors.
The next thing is you should not use self-leveling overlay material to get your concrete floors. This material is brittle and will crack excessively when the plywood moves a little bit. If you need guidlines on how to install concrete floors on a second story follow the link http://mvlconcrete.com/blog/upstairs-concrete-overlay-acid-stained/ . If seen many people try to use self-leveling material and then they have a huge mess to clean up when it fails.
The first concrete floor we did on a second story was about 5 years ago, and so far there has not been any major cracking. There are a few hairline cracks that are not opened up; you mainly see the crack because of the color on the surface. So don’t expect the concrete floors to have minor cracking.
If you have any questions or are looking for someone to install concrete on the second story of your house please feel free to email me at firstname.lastname@example.org or call 210-422-6116.