Open-Plan Kitchen Extensions: Design Ideas for Modern Living

Open-plan kitchen extensions have been the most requested project on my books for the past decade. Everyone wants that bright, sociable space where cooking, eating, and living come together. But there's more to it than knocking down a wall and fitting some bi-folds. Let me walk you through the practical decisions that make these spaces actually work.

Layout Options: Which Works for You?

The right layout depends on your plot shape, how you use the space, and what you're cooking. Here are the main options I build:

Kitchen at the Back (Garden-Facing)

Pros: Best natural light on your work surfaces, seamless connection to outdoor dining, keeps cooking smells near the extractor vent.

Cons: You're facing the garden while cooking (nice, but you can't see guests arriving), the kitchen gets the prime view while the sofa area is further from the light.

Kitchen at the Front (Living Area Garden-Facing)

Pros: Living and dining areas get the garden view and bi-folds, kitchen can be partially hidden from the main space, works well if you have a side utility.

Cons: Kitchen may be darker, requires careful planning for extractor ducting, may feel less integrated.

Kitchen in the Middle (Central Island)

Pros: Chef faces the room and guests, island becomes the social hub, good for entertainers.

Cons: Requires a larger footprint to work well, island plumbing and electrics add cost, need a serious extraction solution.

Glazing: Bi-Folds vs Sliding Doors

This is the question I get asked most often. Both have their place, and the right choice depends on how you'll actually use the space.

My honest view: unless you genuinely open your doors wide regularly (and in London's climate, that's maybe 30 days a year), sliders often make more sense. They give you cleaner sightlines when closed, which is how they'll be 90% of the time.

Heating: The Problem Everyone Ignores

Here's something architects don't always mention: that wall of glass is beautiful, but it's also a massive heat loss. A 4-metre run of bi-folds, even with good double glazing, loses far more heat than a brick wall would.

You have options:

• Underfloor heating: Works brilliantly in extensions. Even heat, no radiators taking up wall space. Budget £60-£100 per square metre installed for a wet system.
• Trench heating: A grille in the floor in front of the doors with a heat emitter below. Counteracts cold downdrafts. £800-£1,500 per metre.
• Oversized radiators: Cheaper option. Put a large radiator on the return wall. Less elegant but effective. £300-£600.
• Triple glazing: Reduces heat loss but adds 30-40% to glazing costs. Worth considering if budget allows.

Zoning: Making Open-Plan Work in Practice

"Open plan" doesn't mean one undifferentiated space. The best open-plan extensions have clear zones that flow together but are still distinct. Here's how to achieve it:

Floor Finishes

Use tiles or polished concrete in the kitchen zone, then switch to engineered wood in the living area. The transition creates a visual break without walls. Keep the same tone family so it flows.

Level Changes

A step up or down of 150-200mm can define a "snug" area or dining zone. Use this carefully – it adds cost and isn't great for accessibility – but it works brilliantly in the right space.

Ceiling Details

Drop the ceiling height over the kitchen (2.4m works well) while keeping it higher in the living zone (2.6-2.7m). This creates intimacy in the cooking area and drama in the living space.

Furniture Arrangement

A sofa with its back to the kitchen creates a boundary without blocking light or flow. Similarly, a dining table placed perpendicular to the kitchen acts as a transition.

Lighting: Plan This Early

Lighting is often an afterthought, but it really shouldn't be. Different zones need different lighting:

• Kitchen work areas: Bright task lighting. Under-cabinet LEDs (£200-£500 for a decent run) plus downlights over the island and sink.
• Dining zone: A pendant over the table creates focus. Put it on a dimmer. Height should be around 700mm above the table surface.
• Living zone: Softer, layered lighting. A mix of floor lamps, table lamps, and perhaps recessed accent lighting. Avoid relying solely on downlights – they create a flat, clinical feel.
• Feature lighting: LED strips in ceiling details, lighting integrated into joinery, or a statement fitting can add character.

My rule of thumb: plan for at least three separate lighting circuits in an open-plan space, each on a dimmer. This lets you set the mood for cooking, dining, or relaxing.

Practical Decisions That Matter

A few final thoughts from years of building these spaces:

• Don't skimp on the extractor: Budget at least £800-£1,500 for a unit that moves enough air. Recirculating extractors are pointless in a kitchen where you actually cook.
• Position the sink carefully: Facing a wall is boring but practical. Facing the room means everyone sees your washing up. Island sinks need good drainage falls.
• Think about acoustics: Hard surfaces (tiles, glass, concrete) reflect sound. A large open space with all hard surfaces is noisy. Add soft furnishings, rugs, and consider acoustic panels if you're going for an industrial look.
• Include a utility room if you can: Even a small one. Somewhere to hide the washing machine, tumble dryer, and cleaning gear keeps the kitchen clean and calm.