The roof is too hot, want to install insulation, with what material and light and good?

If the roof is too hot and you want to make a heat insulation layer, I personally recommend using XPS extruded plastic board is a very good choice. This kind of sheet is lighter in weight, and the construction is also relatively simple and fast. In fact, before their own homes have used XPS extrusion board to do insulation, I feel that the use of the effect is very good. And in terms of price is also very affordable.