Ceramzit. This insulation material is considered quite effective, but in the case of its application there are a number of restrictions. The material can only be used on an unexplosable pitched roof. It is about the fact that it is impossible to visit the roof often, since it is unsafe and inconvenient to move through a rather loose material, since gestures can form.
If a decision was made to use expanded clay filler, then you will need to make a screed of cement. Of course, this option will not provide for the presence of the attic on the roof, as well as technical or residential premises. For them, he is unsuitable and simply useless. This material is not used during insulation of the flat roof from the inside.
Mineral wool. For insulation, this material should put a crate from the beam. Its thickness should be the same as the thickness of the insulation, while the insulation should be placed between the crate.
The logs are laid on these logs (for the most part chipboard). The same situation with polystyrene, but in this case, the crate is not required, since the sheets will fit closely.
Penoplex panel. Many consider it the best option for warming the roofs, since this material on one side has a glued chips and cement film, which allows you to lay it directly on the roof and use it.