Almost every loft in Corby is a trussed roof, and that makes the town unusually consistent to work in once you accept what a trussed conversion actually involves.
A trussed roof has no usable space at all until the structure is reworked. The W shaped webs that make a truss efficient are also what fills the roof void, and they cannot simply be cut out. A conversion means introducing new structure to carry the roof and the new floor independently, then removing the redundant truss members. That is proper structural work, it is entirely routine, and it is not the same job as opening up a cut roof with purlins.
The practical consequence is that anybody quoting a Corby loft at the same rate as a Victorian loft somewhere else has not been up there. We would rather explain that at the quotation than have you compare two prices that are not for the same work.
Head height is generally reasonable on the larger house types and marginal on the smaller ones, so we measure rather than assume. The permitted development volume allowance is forty cubic metres on a terrace and fifty on a semi or detached house, and on these plots a rear dormer inside that allowance is usually achievable without an application.
Escape, fire separation and stair position are all Building Regulations matters and all far easier to resolve on paper than after the joists are down. Our loft conversion page goes through the structural options and the order the work happens in.