A loft can be created in between the spaces of your existing roof ,this is a great way to use your roofs space to its full potential. This way you will have no more wasted space and a new room that can be used for any purpose, walls can also be added (Full scale conversions), this is more cost effective and you get much more space, these spaces are considered as a double dwelling. And what's more, it can add considerably to the value of your property.
If you simply wish to use your loft for storage then there shouldn’t be any issues. But, for larger loft conversions, it is necessary to assess the potential in your roof space before making plans. The advice of a builder or architect will be needed.