I live in the top most floor of a flat. Is it worth to insulate the roof (from inside) with styrofoam(thermocole) to reduce the airconditioning load. Is it really economical with respect to cost of insulation and savings gained? Any experiences?
if u mean roof as just below the shingles this is not recommended as it will cause the shingles to become very hot and prematurely fail,,the best way to lower the heat in an attic is ventilation,,if u have an attic its best to insulate the floor of the attic and lots of ventilation
You want to insulate at the ceiling joist level, not at the roof-rafter level and provide ventilation for the remaining cavity. You also want to make sure you have the correct vapor barrier. But you do not want to insulate directly below and contacting the roof deck. One of the difficulties with rigid insulation is making it fit correctly and without gaps. So be careful of that. You may have to supplement the rigid sheets with foam spray at the gaps, around wires and pipes and so forth.
