My 240G is on a Pergo floor. I installed both the floor and the tank myself. 6 years later there is no problem.
In my case the tank is on the ground floor, but there is a basement underneath it, and the studs run parallel with the length of the tank, which is the worst case scenario for the Pergo. With a concrete ceiling you are good as gold :thumb:
BTW - I had a spill to the tune that I had to restore the suspended ceiling in the basement under the tank. With the Pergo you just mop up the water, and you see not a trace of damage. My wife also had water spill onto it from over-watering the plants, and we didn't discover the puddle until a day later. Same story, mop up the water, and the Pergo looks like new. Good stuff!