The first job on a Paddington loft is to establish whether the building can carry one at all, and that is a tenure question as much as a structural one. The area is flat-led — mansion blocks, converted flats and newer canal-side apartments alongside the surviving stucco terraces — and in most of that stock the roof is not part of any single flat's ownership. A purpose-built mansion block holds its roof communally; a converted period terrace usually keeps the roof with the freeholder. The buildings that genuinely convert are the terraces still in single-family ownership and the upper maisonettes whose lease includes the roof space directly above them. We check that ownership before anything else, from the title and the lease, because it decides whether there is a project to design rather than a wish that will never leave the roof.
Once ownership is clear, air-rights and a Licence to Alter set the terms. Where the roof belongs to a freeholder or a management company, converting into it means acquiring the airspace or securing express consent to build in it, then documenting the works to the standard the lease and the managing agent require — structural interest in the roof, waterproofing and the new weather line, access for construction, and the effect of the added storey on the demise below. That consent package is frequently the harder half of a Paddington loft, and it runs on its own legal timeline alongside the planning route rather than after it. We prepare the Licence to Alter drawings and the supporting information early, because a planning consent is worthless if the airspace consent behind it never follows.
The roof you start with dictates the option. Paddington's stucco terraces frequently hide a shallow roof behind a parapet, which can suit a mansard or a set-back dormer that stays below the parapet line and barely changes the street elevation. A rooflight conversion keeps the existing roof shape and raises the fewest planning questions, but adds the least head height. As a rule of thumb you want roughly 2.2 to 2.4 metres under the existing ridge before the new floor build-up is added, and the finished room has to hold that height across enough of its footprint to be usable — so on the shallower roofs the pitch and the ridge height decide whether you gain a genuine room or an awkward space you can only stand upright in along the centre. We measure that before committing to a design.
Party wall exposure in Paddington is rarely a simple two-neighbour affair. In a terrace the new roof structure — typically steel beams bearing onto the existing walls, with alterations to the ridge, purlins and rafters that a structural engineer designs and calculates — usually bears into the party walls shared with the houses on either side, engaging the Party Wall etc. Act 1996 and the notices that go with building on the line of junction or near a neighbour's structure. In a converted building there is a further, vertical layer: the flat or maisonette directly below is a separate demise, so acoustic separation to that home, the freeholder's structural interest in the roof and the notifiable works between the two dwellings all have to be settled before construction, not discovered during it.
Fire and stairs are where a top-floor conversion is made compliant, and in Paddington they are often what decides feasibility. Adding a storey that lifts the top floor above the 4.5-metre threshold triggers a higher standard: a protected stair enclosure running to a final exit, fire-rated doors — typically FD30 — to the habitable rooms off it, and mains-powered, interlinked smoke alarms throughout. The new stair itself must satisfy the going, rise and headroom rules of Approved Document K, and it has to land with full headroom over it. In a maisonette that stair consumes space within your own demise on the storey below, which is often already tight, so we resolve its position and the escape strategy at feasibility, because together they decide whether the roof space is worth converting at all.
In the conservation setting the deciding question is how the new roof reads against the existing skyline. Where a Paddington address falls within Paddington Green, Bayswater or a Westbourne context — something confirmed address by address rather than assumed from the street — a mansard concealed behind the parapet gives the street elevation the best chance of support, and a rear dormer is kept deliberately subordinate: set down from the ridge, held in from the sides, and slated or clad so it recedes against the existing slope. Changes to a front or canal-facing slope are the hardest to justify, and near the canal basin the visibility of a roofline from the water and the opposite bank can matter too. We design the roofscape to the specific building and its setting, then set the case out fully in the planning drawings and the supporting statement.
