A kitchen island is the most requested feature in a London kitchen renovation. Getting the proportions, services, and specification right requires more thought than most clients anticipate.
The kitchen island has become the defining feature of the contemporary London kitchen. In a rear extension where the kitchen opens to the dining and living space, the island anchors the room, creates a sociable workspace, and provides storage and seating that a perimeter kitchen cannot. Done well, it transforms how the space functions. Done poorly — wrong size, wrong orientation, wrong services — it blocks circulation and becomes a frustration.
This guide covers the design principles, services considerations, and realistic costs for a kitchen island in a London renovation.
Size and proportion
The single most common error in kitchen island design is making it too large. An island that looks impressive on a floor plan can make the surrounding circulation routes uncomfortably narrow in practice. Building regulations require a minimum 900mm clear passage around a cooking appliance; for a kitchen used by more than one person, 1,100mm is more workable and 1,200mm is comfortable.
Minimum island dimensions for practical use: 900mm wide × 1,200mm long. This gives a comfortable work surface with room for two people to sit at one end on bar stools.
Standard dimensions in a generous London kitchen extension: 1,000–1,100mm wide × 1,800–2,400mm long. This accommodates a hob on the island with an overhead extraction hood, seating for three at one end, and adequate perimeter circulation on all sides.
The ceiling height matters for an island with overhead extraction. A pendant hood over an island requires a finished ceiling height of at least 2,600mm to allow 900mm between the hob surface and the hood base (the minimum for effective extraction) and still clear head height. In a Victorian terrace with standard 2,700mm ground-floor ceiling, this is achievable. In a garden flat with a lower ceiling, extraction design requires care.
Services in an island
The services decision is the critical early design question — and one that must be resolved before the kitchen design is finalised, because routing services to the island is much easier during the structural phase than after the slab is poured.
Hob on the island: Requires a gas supply (if gas hob) or a 32A or 40A electrical circuit (if induction), routed through the floor or structure. Also requires extraction — either a ceiling-hung hood above the island, a downdraft extractor integrated into the island surface, or a recirculation unit within the island.
Sink on the island: Requires cold supply (and hot if desired), waste pipe, and an air gap or trap. A waste run from the centre of a room to the stack at the perimeter wall requires careful fall management — typically routed beneath the structural slab or in a raised floor section. This must be designed before the slab is poured.
Power outlets: An island without any electrical outlets is immediately limiting. Build in at least two double sockets, ideally in a recessed island power module (Hafele, Buster + Punch, or similar) that sits flush with the worktop or in the end panel.
Neither hob nor sink: A prep island with only power outlets is the simplest and least expensive option. It gives work surface, storage, and seating without the services complexity. For clients who want the aesthetic of an island without a major services installation, this is the right starting point.
Worktop material
The island worktop is a focal point and takes the most wear. The main options:
Natural stone — marble, quartzite, granite: Marble is beautiful and takes a patina with use; it is not for clients who want a pristine surface. Quartzite has better stain resistance than marble with a similar aesthetic. Granite is the most durable natural stone for a kitchen. All natural stone requires sealing on installation and periodically thereafter.
Engineered stone (Silestone, Caesarstone, Dekton): More consistent in colour and pattern than natural stone, highly durable, non-porous, and does not require sealing. Dekton (ultra-compact surface) is the most heat-resistant. These products are available in very large format slabs — a 3,200 × 1,600mm slab can provide a seamless island top without joins.
Solid timber: Warm, tactile, and repairable. Requires oiling, and should not be used as a chopping surface with a sink alongside it. Oak, walnut, and iroko are common choices.
Stainless steel: The choice for a professional kitchen aesthetic. Durable, heat-proof, and hygienic. Shows every scratch, but these become part of the character over time.
Storage and seating
An island with base cabinets provides significant additional storage. Standard options: drawers (the most useful for a kitchen), pull-out shelves, wine rack, integrated appliance (microwave, warming drawer, wine fridge). Deep drawer stacks (three × 200mm or two × 300mm) are the most functional storage format in a kitchen island.
Seating requires an overhang: a minimum 300mm overhang for stool seating, 400mm for comfortable leg room. The standard stool height for a 900mm worktop is 650–680mm (bar stool).
Realistic costs
| Specification | Approximate cost (exc. VAT, island only) |
|---|---|
| Painted MDF island, laminate worktop, no services | £3,000 – £6,000 |
| Painted or timber island, stone worktop, power outlets only | £7,000 – £14,000 |
| Island with hob and ceiling extraction, stone worktop | £15,000 – £28,000 |
| Island with hob, sink, integrated appliances, premium stone | £25,000 – £45,000 |
These figures cover the island unit and worktop. Extraction hood, hob, sink, and tap are typically supplied by the client and installed by the contractor.
ASAAN has designed and project-managed kitchen islands as part of rear extension and whole-kitchen renovation programmes. If you are planning a kitchen renovation that includes an island, contact us to discuss the services routing before your slab design is finalised.
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