The opening move on a West Hampstead loft is a tenure check, not a design study. A large share of the stock that reads as a Victorian or Edwardian house from the pavement has been converted internally, and the top-floor occupier is a flat owner or an upper-maisonette leaseholder rather than a householder. The roof void above the ceiling can feel physically continuous with the flat and still not be demised to it: in many leases the roof, the roof space, the main structural walls and the structure between flats are retained by the freeholder. Until the lease and the title plan have been read and the demised area is understood, a dormer study is a drawing of someone else's asset. We gather the lease, the title plan, the freeholder's rules and any record of previous alterations to the building before roof geometry is discussed, because that evidence decides whether the project exists at all.
If the answer is that the roof void is not yours, the project does not necessarily stop — it changes shape. The usual route is to seek the freeholder's consent to acquire or use the roof space and to proceed under a Licence to Alter, a private contractual consent that runs entirely separately from planning permission. Freeholders and their surveyors typically want to see structural proposals, drawings, method, insurance and the effect on the flat below before they will agree, and their timescale is not Camden's. Running the Licence to Alter in parallel with the planning application is what keeps a West Hampstead loft on programme; running it afterwards is what stalls one. It is also why we treat the freeholder's surveyor as a genuine consultee on the drawings rather than as a signature to be collected at the end.
Where the property is a house and the roof is unambiguously yours, the constraint moves to the roofscape. The neighbourhood-plan evidence for the West End Green Conservation Area describes a homogeneous piece of Victorian and Edwardian domestic architecture, and homogeneity is a design instruction: the terraces run with a consistent ridge, eaves and rear-slope rhythm, and a roof addition is judged by whether it holds that rhythm or interrupts it. On streets of the Parsifal Road type, the useful exercise is a precedent survey of the rear roofs along the terrace rather than a copy of the one dormer approved three doors down under a different ownership and a different designation. A box dormer that swallows the whole slope reads very differently from a set-back dormer leaving the eaves, ridge and party-wall lines legible. The same logic governs the roof terrace clients often ask for: a terrace looks into rear gardens across a narrow NW6 plot in a way a dormer window does not, and its balustrade is a visible addition to a roofline described as coherent.
Structure on a converted building is the second technical surprise. A Victorian roof was built to carry itself, not a habitable floor, so a conversion means new floor joists spanning between the flank and party walls, a new ridge or purlin strategy, and load paths that have to be traced down through a building whose lower floors may already have been opened up during a previous conversion. In a converted house the ceiling you are working above is another household's, so acoustic separation and fire separation between dwellings become mandatory rather than optional, and the beam bearings may land on walls that are party structures in the legal sense. We survey what is actually there, rather than what the original builder is assumed to have done, because previous conversions in NW6 have already moved a great deal of structure and services.
The staircase and the escape route decide more West Hampstead loft layouts than the dormer does. Adding a storey changes the fire strategy for the whole dwelling: the stair usually has to become a protected route, doors and linings have to be upgraded, and in a maisonette the escape route may pass through space that is shared with another flat. Head height at the top of the new stair is the constraint that most often reshapes a design, because it has to be found within an existing roof, above an existing landing, without stealing the room below. We set the stair position, the head height and the escape strategy first, and let the dormer follow from them — the reverse order produces a handsome roof drawing containing a bedroom that cannot lawfully be reached. On a maisonette, that escape route is also the point at which the freeholder's surveyor takes a close interest, which is another reason to fix it early.
The last layer is comfort in a new top-floor room. West Hampstead has a significant number of homes on railway-corridor and station-edge elevations, and a loft bedroom is the room in the house closest to that exposure and least protected by other buildings. If the ventilation strategy is 'open the rooflight', noise can undermine the room the conversion was built to create, so glazing specification, background or mechanical ventilation and overheating risk under an insulated slope belong in the technical package before a contractor prices the work — not after. Our route from there is a coordinated one: tenure and roof-ownership triage, a measured survey, the planning route confirmed with Camden, the Licence to Alter run in parallel where the property is a flat, then the building regulations and technical package. We do not promise approval; we make the case a case officer and a freeholder can both follow.
