Costing a Kitchen: Runs, Worktops and What Is Behind Them

The doors are the cheap part

Put a fully priced kitchen into its parts and there are six of them: cabinetry, worktop, appliances, the services behind the walls, the finishes that follow the units in, and a contingency. The showroom quote is the first of those and part of the second. On a kitchen priced honestly all the way through, the cabinetry share of the total is routinely under half — and when a household discovers that late, it is because they spent their negotiating energy on the only number anyone showed them.

The share matters more than the total, because it tells you which way your money is leaning against a simple test of reversibility. A door front is four screws. A handle is two. A worktop is a day's work to lift and replace once the sink is disconnected. A circuit run in a chased wall behind a tiled splashback, a waste branch cast into a floor, a duct route through a ceiling void — those are the kitchen. Changing any of them later means taking the kitchen out to reach them, which is why the sensible instinct when a budget is tight runs opposite to the showroom's: hold the services line and take the money out of the doors.

Contingency on a kitchen behaves differently from contingency on a project you can survey, because the evidence is hidden behind the thing being removed. Nobody knows what the plaster behind the units looks like, what gauge the hob circuit is, which direction the waste runs, or how far out of level the floor is, until the day the old kitchen leaves in a skip and the new one is already on a lorry. Fifteen per cent is a floor rather than a cushion, and on most jobs it is spent in the first week.

Worktop is bought by the slab and measured after the units are in

A stone or engineered worktop is not ordered from your drawing. It is templated on site, in the finished room, after the cabinets are fitted, levelled and fixed, because a millimetre of error in the run becomes a visible gap against a wall. That sequence carries a cost nobody quotes: one to three weeks between the units going in and the worktop arriving, with no work surface and no sink. The honest way to budget it is as the price of eating out for a fortnight rather than as a rounding error.

The unit of purchase is the slab, and the slab has a published size in the producer's own fabrication literature. Every run longer than that dimension contains a joint, and where the joint falls is a design decision — behind the hob, at a corner, mid-run in the window light. If you do not make it, the fabricator makes it on the basis of yield. Cutouts are priced individually: sink, hob, taps, drainer grooves, upstands, window sills, and the polished internal edge an undermount sink needs. Ask for the cutout schedule alongside the area, because a small kitchen with five cutouts can carry more fabrication cost than a larger one with two.

The area charged for is developed area, not run length: the return around an island, the overhang where stools go, the upstands, and any splashback carried up in the same material. Measure it that way before comparing two square-metre rates, because a quote that omits a full-height splashback is cheaper for a reason that has nothing to do with the material.

Material choice is where maintenance quietly enters the budget. Timber is refinishable, which means it is also a thing you will refinish. Laminate is unrepairable at the joint but replaceable cheaply. Stones differ from each other on sealing, on heat, and on how they behave at a narrow section between two cutouts — the strip between a hob and a sink is the piece that fails, and it is worth asking a fabricator what minimum width they will warrant before the layout is fixed.

1. Fix the sink, tap and hob choices before the templater is booked, and have the actual items on site — a template is cut around the specific product, not around a category.
2. Have the base units fitted, levelled and fixed to the wall, with any island frame secured to the floor, before the appointment.
3. Decide the joint positions with the fabricator standing in the room, in the daylight the room actually gets.
4. Confirm the overhang on every exposed edge, and any support a breakfast bar needs, before the template leaves.
5. Book the plumber for the day after the worktop fit rather than the day of it, and expect the sink to be dry until then.

What the circuits behind the units are being asked to do

A kitchen fitted in 1995 ran an oven, a hob, a fridge, a kettle and a toaster. The one being drawn for you runs an induction hob, a fan oven, a combination microwave, a dishwasher, a washing machine, a tall fridge-freezer, an extract hood, a boiling-water tap and eighteen light fittings. The cabinetry changed visibly; the electrical demand changed materially, and it is the part of the job that most often turns out to be bigger than the room suggested.

In the United States the answer is prescriptive and worth reading before a layout is agreed. Section 210.11(C)(1) of the National Electrical Code requires at least two 20-ampere small-appliance branch circuits for the receptacle outlets in the kitchen and the rooms sharing them, and Section 210.52(B) restricts what else may sit on those circuits. Section 210.52(C) governs receptacle placement along countertop and work surfaces, which decides where your sockets go before your tiler does. Section 210.8(A) requires ground-fault protection in kitchens and its scope has widened across recent editions, so confirm the adopted edition rather than assuming a device sits outside it; Section 210.12 brings arc-fault protection to kitchen outlets too. Behind all of them sits Section 110.3(B), which makes the manufacturer's installation instructions enforceable — the clause that turns a dishwasher's dedicated-circuit note into a requirement.

In the United Kingdom the reference is BS 7671, the IET Wiring Regulations, and the questions are the same ones in a different currency: how many final circuits serve the kitchen, whether the socket circuit is a ring or a radial, and what the hob may sit on once the diversity allowances published in the IET On-Site Guide are applied — the household-cooker allowance takes the first tranche of load in full and a proportion of the balance, plus an addition where a socket-outlet is built into the control unit. Two things trip people. An induction hob and a boiling-water tap on one circuit will find their own limit at breakfast time. And in England a new circuit in a dwelling is notifiable under Approved Document P, where the kitchen stopped being a special location in the 2013 revision — so replacing a socket is not notifiable and running the hob supply is. Wales did not follow that change and still counts a kitchen among the notifiable locations, and Scotland and Northern Ireland work to building regulations of their own, so check which document your address sits under before deciding the work is exempt.

The constraint that arrives late is the board. Spare ways, the protection already fitted, the condition of the main earthing conductor and the bonding to the incoming water and gas services are things an electrician establishes in twenty minutes and that nobody establishes until the job is priced. A full consumer unit or undersized bonding means the kitchen has just bought a board change and a day's work no showroom quote has ever contained. Have that looked at before you sign the order, not before first fix.

Lighting is the quiet load. Individual LED fittings are small, but a kitchen scheme adds them in quantity — downlights, under-cabinet strips, plinth lights, island pendants, a light rail in the cornice — and hangs them off whatever circuit already serves that floor. Count them against the breaker actually protecting them, using driver input wattage rather than the lamp's stated equivalent, which is a marketing number and not a load.

The waste run is the line that stops a layout

Sockets go anywhere the wall goes. Waste does not, because it runs on gravity. The moment a design moves the sink to the window — which is what almost every kitchen design does — someone has to answer whether the branch reaches the stack at a fall the code allows, inside the depth available under the floor.

The numbers are tabulated, not invented. The International Plumbing Code sets minimum slopes for horizontal drainage piping by size in Table 704.1, the Uniform Plumbing Code gives the equivalent, and the familiar quarter-inch-per-foot figure belongs to the smaller sizes a kitchen branch uses. In England and Wales, Approved Document H tabulates maximum branch length and gradient band by pipe size and fixture, with BS EN 12056-2 behind it; a sink branch beyond that length needs resizing or ventilating rather than optimism. Both regimes protect the same thing at both ends of the range: too shallow and the branch does not clear itself, too steep and the water outruns the solids and the trap seal siphons away — which is how a kitchen that was fine in February starts smelling in July.

Two variants cost meaningfully more than the drawing implies. An island sink takes its waste under the floor, so a suspended timber floor means lifting boards and notching or drilling joists within the limits the structural guidance allows, and a ground-bearing slab means cutting a channel in concrete — a different trade, a different day, and a real question about whether the layout is worth it. The second is the appliance connection: dishwashers and washing machines want their discharge arranged as their own installation instructions specify, and a shared trap taking two appliances and a sink is the arrangement that comes back as a blockage.

The macerator or pumped waste is a legitimate answer in a flat where the stack is on the far wall, and a last resort everywhere else. It converts a passive assembly with a fifty-year life into an appliance with a service interval, a failure mode, a noise and a list of things that must never go down that sink — in the one room where somebody is always washing something.

The floor is bought twice, and the second time is the expensive one

Lift a kitchen out and you find the archaeology. Under the units, whatever was there when they were fitted, often the original surface with nothing done to it. In front of them, a finish laid up to the plinth line and stopping — sometimes three of those in sequence, each over the last, so the level rises twenty millimetres a generation and the back door has been trimmed twice. That is why a fitter's quote carries a line saying make good the floor with no quantity beside it: nobody could have quantified it.

Flatness is the specification that turns that line into a number, and it is written down. BS 8204 defines surface regularity classes measured under a two-metre straightedge — three, five and ten millimetres of deviation for classes SR1, SR2 and SR3 — and the finish chosen dictates which one it needs. ANSI A108.02 tightens the tolerance sharply for tile with any edge of fifteen inches or more, which is most of what a contemporary kitchen specifies; BS 5385 covers the tiling itself and BS 8203 the resilient coverings. Take a straightedge across the bare floor in both directions and write down the worst gap. That one measurement decides whether floor preparation is a bag of compound or a day of work.

Then there is the discovery that stops the job rather than costing it. A kitchen floor laid before 2000 may include thermoplastic or vinyl tiles bedded in black bitumen adhesive, and both are recognised asbestos-containing materials. In Great Britain the duty sits under the Control of Asbestos Regulations 2012, with HSG264 covering surveys and the HSE Asbestos Essentials task sheets covering the work; in the United States the equivalents are 40 CFR Part 61 Subpart M and OSHA's 29 CFR 1926.1101. The instruction is short and worth more than any figure on this page: if you find tiles of that vintage, stop, do not sand, grind or dry-scrape them, and have the material identified before anyone lifts another one.

The last floor decision sets how expensive your next kitchen will be. Laid across the whole room before the cabinets arrive, the finish costs more material now and makes any future change trivial. Stopped at the plinth line, it saves the material under the carcasses and welds this layout in place, because the next kitchen inherits a hole exactly the shape of this one. There is a second consequence at appliance height: lay twenty millimetres of new floor in front of an integrated dishwasher set to the old level, and the machine no longer comes out for service without the floor being cut.

Choosing the finish by the year rather than the square metre

Two floors quoted per square metre are not comparable until you know how long each one lasts in a kitchen, which is a harsher environment than the showroom sample suggests: standing water at the dishwasher door, point loads from a full fridge-freezer on four small feet, grit tracked in from outside, and heat and sunlight in whatever the window gives. Divide installed cost by realistic service life and the ranking between a mid-price engineered board and a cheap laminate frequently inverts.

One caveat belongs on the expensive side of that comparison. A kitchen floor is usually replaced when the kitchen is replaced, not when the floor wears out, and if you are the sort of household that reworks a kitchen every fifteen years then a material that would last forty is being asked to deliver fifteen. That caps the useful life you should enter, and it is a legitimate reason to spend less on the floor and more on the circuits underneath everything.

What the annualised figure cannot see is worth listing before you let it decide. Whether the finish suits underfloor heating, and whether its thermal resistance is inside the emitter's limit. What it does to impact noise in the room below, which is why the flat downstairs cares about your kitchen. Comfort underfoot, in the one room where people stand for an hour at a time. The cost and mess of lifting the old covering, paid once per replacement and therefore favouring the longer-lived option again. And the fact that a floor you dislike gets replaced early whatever the arithmetic said.