The first question on a Northampton loft is head height, and in the terraced quarter the answer varies more than you would expect from the outside.
These houses were built to a budget, but they were built tall for their footprint, and some of them have better roof space than their frontage suggests. Others have almost none. We measure at the quotation rather than guessing, because the difference between two metres along the walking line and a metre and three quarters is the difference between a room and an expensive storage cupboard.
Where the height is there, the older roofs are cut, with rafters and purlins that can be opened up and strengthened. The purlins are the members doing the real work, and where a previous owner has cut one for a hatch or a tank the roof has been quietly weakened. That gets found at the survey.
Out on the estates the roofs are trussed, which means the structure gets reworked rather than strengthened. Routine work, and not the same job or the same price as a cut roof.
The permitted development volume allowance is forty cubic metres on a terrace and fifty on a semi or detached house. A dormer facing the road is not permitted development anywhere, and in the Boot and Shoe Quarter, where the roofscape of the terraces and the factories reads as one thing, anything visible from the street will be examined closely. Our loft conversion page goes through the structural options.