Almost every Marylebone kitchen enquiry resolves into one of two quite different projects, and the deeds and the section decide which one you have before the design does. In a townhouse the kitchen has usually inherited the old service floor at lower-ground level, behind a front area and, where they survive, the pavement vaults, and often with a small yard or garden at the back. That room does not really want to be bigger — it wants to reach daylight and the outside. In a mansion-block or lateral flat there is no ground to build on and no permitted development right to build with, so the kitchen is not extended at all: it is moved, opened up or replanned inside the demise your lease already gives you, and the freeholder becomes the party whose view matters most. Establishing which project you actually have, and on what tenure, is the first hour of work, because everything after it follows from that answer.
Where the kitchen sits at lower-ground level, the difficulty is levels rather than footprint. The finished floor typically lies below the external ground at the back of the house, so opening the room to a yard or garden means either accepting a flight of steps up from the room to the outside, or forming a sunken terrace with a retaining face to bring the outside down to meet the room. That retained face then has to be drained and tanked, because a kitchen is a habitable room with earth against part of its wall. Head height is the other squeeze: the ground-floor structure above is where it is, and every millimetre spent on insulation, screed and underfloor heating comes out of a ceiling that was never generous to begin with. We measure the existing levels, the yard, any vault line and the soffit before any layout is drawn, because a kitchen designed to the wrong section has to be drawn twice.
A kitchen also wants long, uninterrupted runs of wall, and a Georgian or Victorian plan does not offer them. The wall you want to lose is generally the spine wall carrying the floors and often the stair, the flank of a rear closet wing, or a chimney breast standing exactly where the tall units want to be. All three carry load in some way, so removing them means tracing that load down through the building to something that can take it, not simply cutting an opening and propping it. Deflection matters as much as strength: a beam that sags a few millimetres under load will bind a wide sliding door, and the glazing head is always the first thing to complain. Where the work touches a wall shared with the neighbours on either side — which in a terrace it usually does — the Party Wall etc. Act 1996 runs as a separate statutory process alongside the drawings.
Then the room has to breathe, and in a tall central terrace that is genuinely awkward. A serious kitchen needs ducted mechanical extract to carry cooking moisture, grease and odour out of the building, and a duct has to terminate in outside air by a route of sensible length with few bends. In a Marylebone townhouse the faces available are a front area that Westminster and the estates protect, a rear elevation that may read from a mews or a communal garden, or a long vertical riser threaded up through the house — and in a listed building, cutting that route through historic fabric is itself a consent matter. Recirculation through carbon filters is the fallback where no terminal is acceptable, and the layout has to live honestly with its limits. Electrical capacity deserves the same early check, because an induction hob, an electric oven and a heat pump together can outgrow an older incoming supply.
Light and heat are the last pair to resolve, and they pull against each other. A lower-ground kitchen is naturally dim, so the instinct is to glaze the whole rear wall and add rooflights; do that on a sunny elevation and solar gain lands on top of the heat the appliances already produce, which is how a handsome new kitchen becomes the room nobody sits in during July. Glass specification, shading and background ventilation belong in the design rather than in a remedy bought afterwards. Where the new rear opening or a raised roof begins to reduce the daylight reaching a neighbour's window, Westminster will look at that using the established BRE tests, and right to light remains a separate civil matter that planning consent does not resolve. We test the section against the boundary before the glazing schedule is fixed.
From there the process is the same whichever project you have. We measure the property, confirm the conservation, listing, leasehold and estate position for the exact address, and establish precisely which consents apply — planning where the outside of the building changes, listed building consent where historic fabric is touched, a Licence to Alter where the freeholder's approval is needed, and building regulations approval in every case. Then the room is designed around its structure, drainage and services rather than around a showroom layout, and we produce the drawings the application, the estate surveyor, the building control body and the builder each need. We will tell you candidly where a scheme looks likely to struggle, and we do not promise approval — but we make sure the case put forward is the strongest the building can support.
