http://proloftconversionsbristol.co.uk/how-much-does-a-loft-conversion-cost/
The cost of a loft conversion varies significantly from project to project. Having your loft or attic space converted into an additional room, or for storage, is a great idea – for one, it not only enables you to open up your existing home that little bit more, but it may even add more than a little value to your house.