Polystyrene or Thermawrap for roof insulation?

[farazfastian]

My boarded loft is hardly 3 inch insulated with very old insulation and there is a black thick paper on the roof stapled on rafters but it's loose at many places that i can see tiles. Its really cold upstairs compared to downstairs, so i'm thinking to do insulation in two phases:

First Phase: Will do roof insulation first to see if it makes any difference

Second Phase: Then will look into floor insulation as i'm bit confused how to keep the storage after insulation as joists are not that high

Quick question for first phase: Shall i use polystyrene blocks to fit b/w rafters or thermawrap? could someone also point me to the reliable and affordable brand of whatever you suggest?

Thanks,
Faraz

 

[freddiemercurystwin]

Fit mineral wool insulation often available for about £3 a roll in the sheds at floor level in the loft so above your first floor ceiling. Totally false economy to fit insulation at rafter level in a loft.