Wet kitchen or dry kitchen for your landed home?

Choose the scope by the problem to solve

List what is failing in the current kitchen, such as storage, work surface, movement, ventilation, ageing fittings or an awkward appliance arrangement. Separate those problems from preferences about colour or style. A cabinet refresh may fix how the kitchen looks while leaving an awkward washing route untouched.

Then decide how far the layout moves. Keeping the sink, hob and hood where the pipes, gas and duct already run keeps the work centred on cabinets, worktop and appliances. Moving them, or splitting off a wet kitchen, adds new service routes and sometimes a new wall. If there is dampness or a leak, find its cause before new cabinets close over the area.

Test cooking and cleaning routes

A closed wet kitchen earns its space when frying and wok cooking make enough smoke, smell and grease, and washing up enough mess, that you want them away from where people eat and sit. A door or glass screen keeps the mess in, but it also keeps the cooking air in, so the wet kitchen needs its own hood and a way to get that air out.

Every fitting you put in the second kitchen brings its own connections. A second sink needs a water supply and a waste pipe to a drain. A hob needs a gas pipe or, if it is induction or electric, a power supply that can carry its load. An oven, dishwasher, fridge or coffee machine in the dry kitchen needs power points where each will stand. An island with a sink or hob needs water and waste, or gas or power, brought out to the middle of the room.

That is why a split costs more than its extra cabinets. Each duplicated fitting is the appliance, the pipe, power point, gas line or duct that serves it, the cabinet built around it, and making good the walls and floor those routes pass through. A dry kitchen with a counter, the fridge and a few sockets adds far less work than one with its own sink and hob.

One combined kitchen also suits a room too small to give both halves a usable counter, and it needs only one set of service routes. IKEA's planning advice for any layout is to start from the sink, place the hob and fridge so both are easy to reach, and leave a generous worktop between the sink and the hob. Test that on the plan with the dishwasher and drawers open and a second person walking through.

An island should earn its space through useful work, storage or seating rather than become a default feature. A plain island needs only floor space, with room to open its drawers while someone walks past. Put a sink or hob in it and it needs the same pipes, gas or power as any other sink or hob, plus a plan for the cooking air. For a hob on an island, Bosch makes island chimney hoods that hang from the ceiling and venting hobs with the fan built into the hob.

Freeze appliance requirements before fabrication

Make a schedule, kitchen by kitchen, with the exact model, installation document, cut-out size, power, water or gas needs and replacement route for each built-in appliance. Record whether each model is confirmed or still an allowance. The cabinet maker should not build around a photo or a generic width.

The cut-out is only part of it. Built in under a hob, a Bosch oven needs the ventilation gap given in its manual or at least 30 mm between the worktop and the top of the oven, a gap of at least 5 mm between its front panel and the cabinet, and its power socket inside the area Bosch marks on its drawing or away from the installation space. Bosch adds that measurements can vary from model to model, so a nominal oven width tells the cabinet maker none of this.

Ask the appliance installer to check the chosen models against the cabinet drawing before it goes for fabrication, and agree who checks a later substitution. Changing a hob, oven or dishwasher can move a cut-out, a vent gap or a service point, so update the cabinet drawing and the service positions before anything is ordered or cut.

• Build the appliance schedule

Resolve water, drainage, power and extraction together

Moving the sink, or adding a second one in the dry kitchen, means a new water supply and a new waste route to a drain. Compare that route, and the floor or wall that has to be opened and made good, with keeping the sink where it is. Ask the plumber what can be confirmed now and what depends on opening up.

PUB requires all regulated water service and sanitary plumbing works to be carried out by a Licensed Plumber, and since 1 April 2018 it has been an offence to engage an unlicensed plumber for them. Laying or altering water pipes is regulated work, and so is relocating sanitary piping. PUB's list of simple works that a handyman may do includes replacing a tap or mixer, installing or replacing a sink with the trap below it, and installing a pipe that carries waste water into a floor trap. So swapping a sink or tap in the same place is simple work, while new water pipes to a moved or second sink are work for a Licensed Plumber.

Electrical work at home should be carried out or supervised by a Licensed Electrical Worker, according to EMA, and that includes new or modified wiring and added or extended power points, such as the sockets for an island, an oven, a dishwasher or the fridge in a new dry kitchen.

If the hob runs on piped town gas, moving it or adding one in a new wet kitchen means extending or rerouting the gas pipe. EMA's advice before renovation is to ask City Energy to cut off the supply temporarily and to engage a Licensed Gas Service Worker for any gas service work, and it adds that gas pipes concealed behind a false ceiling must be installed by one. A designer's drawing of where the points go does not replace the licensed plumber, electrician and gas worker.

The hood decides what the closed wet kitchen does with its cooking air. A ducted, or extraction, hood draws the air through a grease filter and pipes it to an outlet on the outside of the house, while a recirculating hood passes it through grease and active carbon filters and returns it to the kitchen. Bosch says most of its hoods can be installed either way, though an adaptation kit may be needed. Its guide puts a hood at least 65 cm above a gas hob and at least as wide as the hob, which sets where the wall cabinets around it can go.

A closed wet kitchen used for frying is where a ducted hood earns its place, since a recirculating one returns the filtered air to the same closed room. Settle the duct route before the cabinets are made. The duct runs from the hood to an outlet outside the house, above or through the wall cabinets or through the ceiling, so agree with the contractor where it leaves the house before the cabinet drawings are released. The ducted and recirculating hood comparison goes through that choice for a landed kitchen.

Choose surfaces with their care routine attached

For the worktop, agree the exact product, joints, edges, cut-outs and support with the fabricator, because a category such as quartz or stone is too broad to settle those details. Read the chosen product's care limits against how you cook. Caesarstone, for example, asks owners to always put hot items on a trivet or heat pad on its quartz and mineral surfaces, so in a wet kitchen decide where a hot wok will land before choosing the slab.

Cabinet fronts have care limits too. Formica's laminate care guidance warns against flooding the laminate, especially near seams, because water can get in and make the board underneath swell. That matters most on the doors, panels and edges around the sink and the dishwasher.

• Compare worktop care before choosing

Compare the whole installation

Give each contractor the same drawings and product list. Ask for named products and quantities, stated allowances and clear exclusions, so an unconfirmed model or a hidden condition shows up as an open item rather than an assumption buried in the price.

Check that each quote covers demolition, protection, disposal, the plumbing, electrical and gas work, wall and floor preparation, cabinets, worktop fabrication, fittings, appliance installation and making good. Identify whether lighting, painting and final cleaning are included. Compare the installed scope before comparing any per-foot rate, because a per-foot cabinet price says nothing about the pipes, gas or duct behind the cabinets. Our look at built-in wardrobe quotes shows what a per-foot carpentry price can leave out.

Agree how changes are decided. A proposed extra should state what triggered it, the work, the cost and the effect on the programme before you accept it. Name who coordinates the carpenter, worktop fabricator, plumber, electrician, gas worker and appliance installer where their work meets.

Plan the period without a working kitchen

Ask the contractor to mark the days when water, cooking and storage will be unavailable, not only the completion date. Decide where the fridge will stand, where a kettle and microwave can be plugged in away from the dust, and where washing up will happen while the sink is disconnected.

In a split kitchen, ask whether the two sides can be rebuilt one after the other, so the dry kitchen keeps a counter, the fridge and a working socket while the wet kitchen is stripped out. Some interruptions still reach the whole house. The piped gas supply is cut off before renovation work starts, and the water may be shut off while new pipes are connected, so ask for those days to be named.

Tie each order to the information it needs, because a cabinet or worktop that cannot be made until a late decision is settled lengthens the time without a working kitchen.

Demonstrate the kitchen in use

At handover, have the installers show each appliance working, where it is switched off or isolated, and how its service points are reached. Open doors and drawers in the order you would use them while cooking. Check the dishwasher and other built-in appliances can be pulled out the way that was agreed.

Record visible defects, unresolved operation issues and responsibility for follow-up. Retain appliance manuals, cabinet and hardware references, worktop care instructions, relevant specialist records and the final drawings.

Check the kitchen tap's label too. Taps and mixers fall under PUB's mandatory water efficiency labelling, and PUB advises buying only fittings that carry the WELS label, in a shop or online, so confirm the label before the tap is bought and keep that record with the installer's confirmation that it fits the sink.