The type of loft conversion you will need depends on a number of factors such as your property type, your budget, and your requirements. The cheapest conversion is usually a roof light conversion, which can start from £25,000 – adding a dormer and an en-suite will add a further £20,000. If you have a small loft with a low ridge a dormer will be essential. If you have a high ridge, around three metres, the likelihood is that a dormer will not be required. The higher your property value, the more you should really, budget permitting, maximise your development to achieve the maximum valuation on your property.