The first question on a Primrose Hill kitchen is not how big but where. In these Victorian terraces the original kitchen usually sits in the rear closet wing or on a lower-ground floor, tucked away from the rooms the family actually lives in. A kitchen extension is therefore often a relocation: the room moves to the back of the garden level, or down into a remodelled lower ground, and everything that served it has to move with it. That decision governs cost more than the footprint does, because a kitchen carried across a house drags its waste, its water, its extract and its electrical load along behind it. We settle the section — which floor the kitchen occupies and how it meets the garden — before drawing a single unit run.
Extract is the constraint people least expect. A hob needs a genuine ventilation rate under the Building Regulations, and on any serious cooking appliance that means a ducted hood, not a recirculating filter. A duct of the diameter required has to leave the room, cross a ceiling void and terminate somewhere on the outside. In a new flat-roofed kitchen already carrying rooflights and a downstand steel, that ceiling zone is frequently the most contested space in the project. Where the duct exits matters as much as where it runs: the terminal lands on a rear elevation whose external surfaces fall under the long-standing Article 4 direction, so its position and finish are a design decision, not a fitting-out afterthought.
Drainage sets the floor. Kitchen waste needs a continuous fall to the existing stack, and in a period terrace that stack is usually where the old kitchen was — not where the new island wants to be. Every metre the sink moves away from it is a metre of pipe that has to fall, and that fall has to be found within the floor build-up. An island sink is the sharpest version of this problem: the run is buried in a slab or a screed with no second chance once it is poured. We set the drainage strategy against the island position at feasibility, because moving a socket later is trivial and moving a waste run under a finished floor is not.
Appliances have become an electrical question. Induction hobs, double ovens and the shift away from gas raise the load on a supply and a consumer unit that were never designed for it, and a period house may be at or near its capacity before a single appliance is specified. We check the incoming supply, the board and the circuit provision early, because an upgrade involves the distribution network operator and takes time nobody has budgeted. Where a gas hob is retained, the supply route and combustion ventilation form part of the design; where it is abandoned, the redundant run and any flue need resolving rather than simply capping and forgetting. A boiler moved out of the new kitchen also needs a home, a flue and a pipework route, and that belongs in the drawings rather than the fit-out.
The structure that opens the kitchen up also determines what can be run through it. Removing the rear spine wall or the closet-wing flank to make one room needs beams, and there is a real choice between a downstand, which is cheap and eats headroom, and a flush beam, which keeps a clean ceiling but occupies the very zone the extract duct and the lighting want. Chimney breasts are the same trade-off: taking out the breast that once served the range wins wall length for units but removes a load path and needs the stack above supported. We coordinate the engineer's beam layout with the duct route and the drainage falls in one exercise, because on a narrow terrace plan they all compete for the same few hundred millimetres.
Opening the kitchen into the hall changes the fire strategy of the whole house. On a Primrose Hill townhouse of four or five floors, the stair is the escape route for every bedroom above it, and the Building Regulations do not accept an escape route that passes through a room containing a cooker. So the fashionable move — knocking the hall, kitchen and dining room into one continuous space — has consequences: it may require an alternative escape, a fire-resisting enclosure retained somewhere in the plan, or a sprinkler system agreed with building control. This is not a detail to be discovered at the technical stage. It shapes whether the open plan people want is achievable at all, so we test it at the first layout.
Because almost every Primrose Hill address is in the conservation area, the shell around the kitchen will normally need a householder application to Camden rather than permitted development, which Article 4 has curtailed here. Camden aims to decide within about eight weeks. The application is judged on massing, materials and the rear elevation; the Building Regulations then judge the ventilation, the electrics, the drainage and the escape. Large glazed kitchens also need to work in July, so we test glazing area against orientation and specify shading or solar-control glass rather than glazing a room that becomes unusable when the oven is on. We design to give a scheme the best case we can build for it, but no architect can promise a Camden decision.
