Kitchen Extension & Open Plan Living London — Planning, Cost & Ideas

Why an Open-Plan Kitchen Extension is the Most Popular Project in London

The combination of a rear extension with a knocked-through ground floor to create an open-plan kitchen-diner-living space is consistently the most requested project at SuperBuilder. It typically adds £50,000–£80,000 to the market value of a London terrace while transforming daily living quality.

What It Involves

Three things happening simultaneously:

1. The extension — a single-storey rear extension of 3–6m depth 2. The knock-through — removing the rear internal wall (and often the chimney breast) and installing a structural beam (RSJ or Flitch beam) 3. The kitchen fit-out — a new kitchen designed to maximise the new extended space, often with an island

Structural Considerations

Removing rear walls in terraced houses almost always involves structural steelwork. The beam spans the opening and transfers the load of the floor above to the remaining walls. This requires a structural engineer's design and Building Control inspection.

In Victorian terraces, this often also involves removing chimney breast at ground floor — which requires additional padstone support and may affect the chimney breast above. Always involve a structural engineer before assuming a wall can be removed.

Cost Totals

Including extension, structural works, kitchen, and full decoration:

- Basic specification: £55,000–£75,000 - Mid-range specification: £75,000–£100,000 - Premium specification (bespoke kitchen, glass roof, specialist finishes): £100,000–£150,000+

Design Ideas That Transform the Space

Glass roof lantern or flat glass roof: Nothing floods a kitchen extension with light like a structural glass roof. Budget £12,000–£25,000 depending on size.

Bifold or sliding doors to the garden: Creates indoor-outdoor living. Bifolds: £4,000–£10,000. Sliding (larger format): £6,000–£15,000.

Kitchen island: The centrepiece of any open-plan kitchen. Requires careful positioning to allow circulation. Budget £3,000–£12,000 for the island cabinetry and worktop.

Contrasting floor materials: A smooth polished concrete or large-format porcelain in the extension, meeting heritage herringbone parquet in the existing house — creates a beautiful transition.

Call SuperBuilder on 0800 530 0853 for a free design consultation and estimate.