Before head height, before the stair, the Bayswater loft question is ownership. Most of the district is leasehold — mansion blocks, converted flats and stucco terraces divided into apartments — and in those buildings the roof structure and the airspace above it are usually retained by the freeholder and sit outside any single leaseholder's demise. That means a top-floor flat owner rarely has the automatic right to build up into the roof; the space has to be acquired or licensed from the freeholder first, and sometimes the lease has to be extended or varied to capture it at all. We establish who owns the roof and what the lease actually grants at the very start, because on a Bayswater flat that answer, not the pitch of the rafters, decides whether a conversion is even available to design — and it is the single fact that most often ends a scheme before it begins.
The stock gives two genuinely different starting points. On a purpose-built mansion block the roof is typically a shared, freeholder-owned structure behind a parapet, and a conversion is an airspace project — negotiated with the freeholder and the other leaseholders, structurally independent of the flats below, and gated by the building's common parts, lifts, tanks and shared services that often already occupy the roof. On a stucco terraced house or a converted-house roof, the question shifts to the roofline itself: a mansard or dormer set against a protected stucco frontage and a continuous terrace parapet, where the conservation reading of the street elevation governs the design and the party walls run between grand neighbouring houses. We scope the two routes differently because their constraints barely overlap, and confusing one for the other is how a Bayswater roof scheme goes wrong early.
Freeholder consent is the spine of a Bayswater roof scheme, not an afterthought. A Licence to Alter from the freeholder — and, on a managed block, sign-off from the managing agent — governs what can be built into the roof, how the works are insured and supervised, and how the common parts and shared services are protected during construction. The licence typically requires the freeholder's surveyor to approve the structural scheme and often the appearance, so we prepare the drawings to answer both the planning authority and the freeholder at once. Where the airspace must be purchased or a lease extended to capture it, that legal track runs in parallel and should start early, because it frequently sets the programme and can take longer than the planning application itself. We treat the licence as a design input from day one, so the scheme we draw is one the freeholder can actually consent to rather than one that has to be unpicked later.
Inside the property, the new staircase usually decides feasibility. It has to rise from the floor or flat below within the going and rise limits of Approved Document K and land with full headroom, and it almost always consumes part of a room or hallway on the storey beneath. In a mansion-block flat that lower floor is fixed and often already tight, so the stair can be the single reason a top-floor conversion does or does not work. We resolve its position and its cost to the floor below at feasibility, because there is little point perfecting a roof design if the only compliant stair sacrifices a bedroom the owner is not willing to lose. Where the storey below is a separate flat rather than part of the same home, the stair may have to land within the applicant's own demise entirely, which narrows the options further and makes early testing essential.
A converted roof needs new structure, and in Bayswater that structure lands on shared walls. Steel beams spanning the roof typically bear onto or into the party walls between adjoining terrace houses or between mansion-block sections, which engages the Party Wall etc. Act 1996: notices go to the neighbours on either side before work begins, and on a block the freeholder and adjoining leaseholders are drawn in as well. Excavation is rarely the trigger here — it is the building on the line of junction and the bearing into a shared wall that brings the Act into play. We identify the notifiable parties early and coordinate with a party wall surveyor so the neighbour process runs alongside the design rather than stalling it. The roof is also where the building's thermal performance is brought up to current building-regulation standards, and on a mansion-block roof the freeholder's structural interest in the existing slab and the integrity of the flats below have to be protected throughout, which shapes how the new structure is designed and sequenced.
In the conservation area the deciding question is how the new roof reads from the street. On a stucco terrace a mansard works best when it is concealed behind the parapet so the front elevation is barely changed, and a rear dormer is kept subordinate — set down from the ridge, in from the sides and clad to sit quietly against the existing slope. Additions visible on a front or street-facing slope, and anything that breaks the continuous run of a terrace roofline, are the hardest to justify. On a mansion block the parapet line and the building's symmetry do the same work, and a scheme that disturbs either reads as an over-development of the roof. We design the roofscape to the specific street, confirm which conservation context governs the exact address, and set out the case in the planning drawings and supporting statement, without ever promising the outcome.
