Kitchen Extension Ideas That Work — What Makes a Great Kitchen Extension?

Kitchen Extension Ideas That Work — What Makes a Great Kitchen Extension?

Introduction

A kitchen extension is one of the most consistently popular home improvements in London — and for good reason. In a city where Victorian and Edwardian terraced houses divide the ground floor into small, disconnected rooms, extending at the rear and opening up the kitchen can transform how the entire house feels and functions.

But not all kitchen extensions are created equal. A well-designed extension creates a genuinely usable, light-filled, connected space. A poorly designed one adds square footage without adding quality of life. The difference lies in a handful of design decisions that are worth getting right before the build begins.

Open the Full Width Where Possible

One of the most common mistakes in kitchen extensions is adding floor area but not width — extending the kitchen forward but leaving the side wall in place. The result can feel like an elongated corridor rather than an open, usable room.

Where the layout allows, opening the extension across the full width of the kitchen — removing the side wall to create a continuous space — produces a dramatically better outcome. The light distribution is better, the room functions more coherently, and the sense of space is significantly greater.

Get the Glazing Right

The choice and placement of glazing is the single biggest determinant of how a kitchen extension feels. The options most commonly considered are:

Bi-fold doors. A popular choice that opens the full width of the rear elevation. They create a strong inside-outside connection when open, and a relatively generous glass area when closed. They require clear floor space for the panels to fold and don't work well if furniture needs to sit directly against the door.

Sliding doors. Offer a larger fixed glass panel with a cleaner sightline. They don't require the floor clearance that bi-folds do and often suit more contemporary interior designs. The operable section is smaller relative to the total glazed width.

Full-width roof light or orangery lantern. Adding a roof light above the extension transforms the quality of natural light. A kitchen extension with both rear glazing and a large roof light feels genuinely different from one without — particularly through the year when the rear doesn't face south.

Fixed glazed panels with a single door. Sometimes the most practical and cost-effective solution. A well-proportioned fixed panel with a slim-framed inward-opening door gives excellent light without the complexity and cost of bi-folds or large sliding systems.

Consider the Kitchen Layout in the New Space

The extension creates more floor area — but the kitchen layout needs to respond to that space properly. Common considerations include:

Where does the run of units go? An L-shaped or U-shaped kitchen often works well in a wider, more open space. A straight galley-style run may leave too much dead space.

Where is the island? Kitchen islands are popular — and a reason many clients extend in the first place. But an island needs adequate circulation space around it: at minimum 900mm on working sides and ideally 1,100mm for comfortable use.

Where is the cooking zone? If the hob or oven is moving as part of the extension, extraction needs to be planned early — including any structural implications of a roof or wall penetration for a flue or extract duct.

Where is the dining space? A dining table at the rear of the extension, adjacent to the doors, is a natural position. Think about how many people need to sit comfortably and plan the space accordingly.

Think About Underfloor Heating

Kitchen extensions are one of the most appropriate places for underfloor heating (UFH). The floor is being built new, the concrete base accommodates electric or wet UFH systems readily, and the open-plan nature of the space suits UFH better than radiators. If you want UFH, make sure it's specified and included before the slab is poured.

Don't Skip External Detailing

The external appearance of a kitchen extension — the roof finish, the brickwork or render, the fascia and soffit details — affects both the planning outcome and the long-term quality of the build. A good contractor will think about how the extension relates to the existing house, not just what happens inside it.

Thinking about a kitchen extension in London?
Contact RCB Design & Build to discuss the design, planning, and build approach for your project.

📞 07359 872594 | contact@rcbgroup.co.uk | www.rcbgroup.co.uk