One reason some people don’t insulate their loft is because they want to use it for storage. The required 270mm of insulation material over the joists would make it impossible to lay boards on top.

But in your bid to save on energy bills, it's worth noting that there are some areas of a home you shouldn't insulate ...

Owens Corning R-15 Polystyrene Board Insulation If you’ve got the budget to spend and want to insulate above your garage to ...