A kitchen is the only room in a home that has to reach outside air. Everything else can be rearranged within four walls; a hob that is genuinely extracted has to push warm, greasy air through the building envelope and out. In South Hampstead that single requirement is what makes the project hard, because the envelope is frequently not yours. The stock here runs to red-brick mansion blocks, large houses long since converted into flats and purpose-built apartment buildings, and in all three the external walls and the roof belong to the building rather than to any one home — held by a freeholder and maintained on everybody's service charge. Cutting a duct through one of them is an alteration to someone else's asset. And on the faces the street can read, Camden's Article 4 material, described as covering the fronts and street-facing sides of single-family houses and converted flats, puts the same small penetration in front of a planning officer. So we start a kitchen at the terminal and work inwards to the island.
Ducting is where kitchen designs quietly fail. A recirculating hood filters and returns air to the room; it needs no route out of the building, and it does not clear steam. A ducted extract does the job properly, but only if the duct is wide enough, short enough and straight enough for the fan to work against — every bend and every additional metre costs performance, and Approved Document F sets the extract and background ventilation a kitchen has to provide in the first place. Where the walls are solid masonry rather than cavity construction, there is no void to conceal the run in, so it has to be plotted through real structure while the design is still fluid: above a ceiling that may also be carrying a new beam, around joists an earlier conversion has already cut about, out through the roof of a new rear addition, or, where a redundant flue survives and can be lined, up inside the chimney. That route is an opening decision, not a late services item.
The second physical constraint is gradient. A sink, a dishwasher and a washing machine all discharge into a waste run, and that run can only reach a soil stack by falling. In a converted South Hampstead house the soil stack commonly runs down the rear elevation, where it may also carry the wastes of the flats above, and every metre the new sink travels away from it has to be bought with fall — taken out of a floor zone that is already oversubscribed. Insulation, screed and underfloor-heating pipes all want that same depth. In a flat, so does the resilient acoustic layer a freeholder will insist on, because your floor is another household's ceiling. The three demands collide most sharply directly beneath an island, which is exactly where owners want the sink. Pumped or macerated waste exists, but it is a mechanical answer to a geometric problem, and it introduces noise, maintenance and a failure mode into the middle of the room. We fix the build-up and the falls with the plan.
Where the property is a whole house, the ambition is usually to lose the rear wall so that the old kitchen, the new addition and the garden read as a single space. That is a structural project before it is a kitchen: a beam, frequently a goalpost frame with columns and padstones taking load down to new foundations, and on a terraced or semi-detached house at least one bearing lands in a party structure. The Party Wall etc. Act 1996 follows from that, as it does from excavating for the new foundations within three or six metres of a neighbour's structure, and it is notifiable whatever Camden decides. The detail that matters most to the kitchen is depth. A flush beam gives an unbroken ceiling — and competes for the same few hundred millimetres as the extract duct, the lighting void and any recessed track. Settle it late and either the duct is throttled to a diameter that cannot move the air, or the ceiling drops in the one position the design could not afford.
Where the property is a flat, the kitchen cannot grow outwards at all, and the freeholder rather than the council becomes the audience whose answer decides the scheme. A Licence to Alter is the normal route, and the managing agent's surveyor tests the same things every time: structure, fire separation between demises, and the acoustic performance of the floor. A lease in this stock may also restrict placing wet areas over a neighbour's habitable rooms, which means the lease, not the layout, can decide where a sink is permitted to sit — so it is read before a plan is drawn. There is a further complication particular to converted houses here, because earlier conversions often left alterations nobody recorded. The stack, the vent line and the joist directions may not be where any surviving drawing claims. Assume the survey is partly investigative: open up where you are permitted to, and establish the real drainage and structure before designing a kitchen around an assumption.
Fire is the constraint that catches open-plan kitchens in flats. A kitchen is the highest-risk room in a home, and in a flat the internal escape route runs from the bedrooms, through the hall, to the front door. Knocking the kitchen through into the living space can put that route through the room most likely to be alight, and the answer has to be designed — a considered layout, a detection and alarm strategy, or a protected route retained elsewhere — rather than left for building control to raise. The appliances bring their own requirements. An induction hob draws a substantial electrical load, so the circuit and consumer unit must be checked and the work certified; a gas hob keeps the existing supply but brings combustion-ventilation requirements and, if it moves, a relocated gas run that in a flat may pass through fabric you do not own. Building regulations cover structure, fire, insulation, ventilation, drainage, stairs and waterproofing. We resolve all of it on paper. We do not promise approval; we make the case on evidence.
