It depends on what your goals are. If you want to keep the room cooler in the summer, then you will need a thicker layer of insulation. If you want to keep the room warmer in the winter, then you will need a thinner layer of insulation. In general, I would recommend at least 3 inches of insulation for flooring. However, if you live in an especially cold climate or if you have serious heating/cooling needs, then you may want to increase the thickness of your insulation.

It depends on the climate. In a cold climate, you'll need a thicker layer of insulation to keep the heat in. In a hot climate, you'll need less insulation to keep the heat out. In general, floor insulation should be at least 5 inches thick. However, if you're in a colder climate, you may want to install a thicker layer of insulation to keep the heat in. If you're in a hotter climate, you may want to install a thinner layer of insulation to keep the heat out.