How to Design a Kitchen Extension Layout
Table of Contents
Step 1: Measure Your Space and Define Your Extension Footprint
Step 2: Understand Kitchen Extension Floor Plans and Layout Types
Open-plan kitchen-diner layouts
Galley and linear arrangements
L-shaped and U-shaped configurations
Matching layout type to your extension shape
Step 3: Plan Your Work Zones and Appliance Placement
Understanding the work triangle and its limits
Adapting appliance placement to your household routine
Sink, hob, and fridge positioning
Testing your layout on a scaled plan
Work zones beyond the triangle
Step 4: Incorporate Kitchen Island Dimensions and Clearance
Step 5: Design Small Kitchen Extension Ideas for Tight Spaces
Peninsula and side-return solutions
Built-in seating and storage
Step 6: Optimise Light, Ventilation, and Material Finishes
Step 7: Use a Free Kitchen Design Planner to Visualise Your Layout
Common Layout Mistakes to Avoid
Frequently Asked Questions
Last Updated: October 10, 2026
Step 1: Measure Your Space and Define Your Extension Footprint
Designing a kitchen extension layout starts with accurate measurements. Measure your existing kitchen and extension space, recording wall lengths, ceiling heights, window and door positions, and structural elements like load-bearing walls or service pipes. Use a tape measure and sketch these on paper or a digital tool.
Define your extension footprint: rear extension, side return, or wraparound. Your plot shape, existing layout, plot boundary, neighbour relationships, access, existing services, and building regulations will guide this choice.
Write down the final dimensions of your extension: length, width, and the total floor area you'll gain. This becomes your planning baseline.
Step 2: Understand Kitchen Extension Floor Plans and Layout Types
Different kitchen extension layout types suit different homes and lifestyles. Match a layout to your extension's footprint, existing constraints, and how your household actually uses the space.
Open-plan kitchen-diner layouts
Open-plan designs remove barriers between kitchen, dining, and living spaces, creating a larger, social environment. Open-plan works best when your extension is large enough to separate cooking from dining without noise and steam affecting seating. Aim for at least 4 metres between the hob and dining table. Use islands or peninsulas to define zones. Install a powerful extractor hood that vents outside, as cooking smells travel further in open-plan layouts.
When open-plan works: Extensions 5 metres or wider with a depth of at least 4 metres. Rear extensions and wraparound extensions suit this layout best.
When open-plan fails: Narrow side-return extensions (under 3 metres wide) or extensions directly off a small existing kitchen often feel cramped with open-plan. Cooking noise and steam will dominate the dining area.
Galley and linear arrangements
Galley layouts have two parallel runs of cabinetry facing each other, efficient for small extensions with everything within arm's reach. Linear layouts place all appliances in a single run along one wall, ideal for narrow extensions. Both maximise counter space and storage in tight footprints.
Galley dimensions: Works well in extensions 2.5 to 4 metres wide and 3 to 5 metres deep. The two runs should be 1.2 to 1.5 metres apart to allow comfortable passage and working space between them.
Linear dimensions: Ideal for extensions under 2.5 metres wide or very narrow side returns. A single run of cabinetry along one wall works in extensions as small as 1.5 metres wide by 3 metres deep.
L-shaped and U-shaped configurations
L-shaped layouts turn a corner, creating two work zones and room for a small island or dining table. U-shaped layouts have three runs, offering maximum storage and counter space but requiring larger extensions to avoid feeling cramped.
L-shaped dimensions: Works in extensions 3 to 5 metres wide and 3 to 4 metres deep. The corner creates a natural work zone. Allow at least 1.2 metres of clearance at the corner junction so two people don't collide.
U-shaped dimensions: Requires extensions at least 4 metres wide and 4 metres deep to avoid feeling cramped. The three runs should be spaced 1.2 to 1.5 metres apart. U-shaped layouts are common in larger rear extensions and wraparound extensions.
Matching layout type to your extension shape
Rear extensions: Open-plan, L-shaped, or U-shaped work well. You have flexibility on width and depth.
Side-return extensions: Galley or linear layouts are most practical. Side returns are typically 1.5 to 2.5 metres wide, too narrow for open-plan or U-shaped without feeling cramped.
Wraparound extensions: Open-plan or L-shaped. Wraparounds give you corner space, which suits L and U layouts.
Narrow plots with existing small kitchens: Linear or galley with a peninsula. Avoid open-plan unless your extension is at least 4 metres wide.
Pro Tip Sketch your extension footprint to scale on paper (1:50 scale works well, 1 centimetre on paper = 50 centimetres in reality). Then draw each layout type into that footprint. You'll immediately see which layouts physically fit and which would feel cramped. This visual test is faster and more reliable than guessing.
Step 3: Plan Your Work Zones and Appliance Placement
A well-organised kitchen extension layout separates work zones so they don't interfere with each other. The classic approach uses the work triangle concept, but it's not a rigid rule, it's a framework for testing whether your appliance positions will support your actual cooking routine.
Real Life Architecture
Understanding the work triangle and its limits
The work triangle connects sink, hob, and fridge. Typical distances: sink to hob 1.2-2.1 metres, hob to fridge 1.2-2.7 metres, fridge to sink 1.2-2.7 metres. Total perimeter should be 3.6-8 metres. However, the work triangle has limits, it assumes a single cook and doesn't account for two cooks, multiple prep areas, dishwashers, or scattered storage.
Adapting appliance placement to your household routine
Before you position appliances, map out how your household actually cooks.
Single cook: Position sink, hob, and fridge within easy reach. Two cooks: Create two work zones with 1.5 metres clearance between them. Entertaining: Position hob and prep areas away from dining zones; use islands or peninsulas to separate. Baking: Position prep surfaces away from the hob in cool areas. Large families: Plan at least two prep surfaces in different locations with efficient fridge and pantry access.
Sink, hob, and fridge positioning
Sink placement: Position near a window for natural light. Ensure at least 0.6 metres clearance from external corners. Avoid positioning directly opposite the main entrance, as this creates a bottleneck.
Hob placement: Position away from doors and windows to avoid drafts. Ensure at least 0.6 metres clearance on either side. Keep at least 1 metre from external corners. Island hobs require a powerful extractor hood directly above.
Fridge placement: Position at least 1 metre from the hob. Ensure the door opens fully (0.7 metres) without obstruction. Leave 0.3 metres clearance on the hinge side if at the end of a cabinetry run.
Testing your layout on a scaled plan
Test appliance positions on a scaled floor plan (1:50 scale). Draw your extension with all walls, windows, doors, and features. Mark appliances to scale, draw the work triangle, and measure distances. Mark circulation paths to ensure people can move without colliding. Check door swings and verify counter space: at least 0.6 metres on either side of the hob and 0.9 metres next to the sink.
Watch Out Common mistake: Positioning the dishwasher next to the sink seems logical, but it creates a bottleneck. If the dishwasher door is open, you can't access the sink. Position the dishwasher at least 0.6 metres away from the sink, ideally on the other side of a run of cabinetry.
Work zones beyond the triangle
Modern kitchens often have more than three appliances. Plan zones for these too:
Prep zone: A clear counter surface, ideally 1.2 metres long, with storage for knives and chopping boards nearby.
Washing-up zone: Sink, dishwasher, and drying space. Position these together for efficiency.
Cooking zone: Hob, oven, and prep surface. These should be within 1.5 metres of each other.
Cold storage zone: Fridge, freezer, and pantry. Group these so you're not walking across the kitchen every time you need an ingredient.
Beverage zone: If you have a coffee machine, kettle, or wine fridge, group these together. This keeps traffic out of your main work areas.
Pro Tip If your extension is large enough, create a "dirty zone" (sink, dishwasher, waste) separate from a "clean zone" (prep, cooking). This prevents cross-contamination and makes the kitchen feel less cluttered.
Step 4: Incorporate Kitchen Island Dimensions and Clearance
Kitchen islands need minimum dimensions of 0.9 by 0.6 metres; larger islands (1.2 by 0.75 metres) offer better workspace. Allow at least 1.2 metres clearance on all sides (1.5 metres for two cooks). If seating is included, allow 0.75 metres per seat. Islands work best in extensions larger than 4 by 3 metres.
Step 5: Design Small Kitchen Extension Ideas for Tight Spaces
Narrow plots and small budgets call for clever solutions. A small kitchen extension doesn't mean cramped or poorly planned.
Peninsula and side-return solutions
A peninsula is like half an island. It's attached to one wall or to cabinetry. Peninsulas save space while offering some of the benefits of an island. They provide extra counter space and can have seating on the outer edge.
A side-return extension on a narrow plot can be just 1.5 to 2 metres wide. Position cabinetry on the outer wall. Use a peninsula or narrow island in the middle to separate the kitchen from the dining area.
Side returns work especially well when your existing kitchen is already tight. The extension gives you breathing room without needing a large footprint.
Built-in seating and storage
Built-in benches along one wall save space compared to freestanding chairs. They also provide hidden storage underneath. A built-in bench with a table works in extensions as small as 2.5 metres by 2 metres.
Tall cabinetry that reaches the ceiling maximises storage without taking up floor space. Use wall-mounted shelves above counters for everyday items.
Corner spaces are often wasted. Install carousel units or pull-out shelves in corner cabinets to make them accessible and useful.
Step 6: Optimise Light, Ventilation, and Material Finishes
Natural light is essential; use large windows or rooflights positioned to avoid glare. Install an extractor hood above the hob; for open-plan layouts, choose a powerful hood that vents outside. Light colours and glossy finishes reflect light and make spaces feel larger. Choose durable, easy-clean flooring like tiles, vinyl, or polished concrete.
Step 7: Use a Free Kitchen Design Planner to Visualise Your Layout
Use free online kitchen planners to test different layouts quickly and see 3D views. These tools are excellent for exploring ideas and communicating your vision to an architect or builder, though they don't account for building regulations or structural constraints. Sketch several options before investing in professional drawings.
Common Layout Mistakes to Avoid
Designing your kitchen extension layout is a process of balancing your needs, your space, and practical constraints. Start with accurate measurements and a clear understanding of how you use your kitchen. Sketch several options. Test them with a free planner. Then work with a professional architect to refine your design and ensure it meets Building Regulations and planning requirements.
At Sd Architecture, we help homeowners turn rough ideas into detailed, buildable designs. We handle the technical side so you can focus on creating a kitchen that works beautifully for your family. Get in touch to discuss your kitchen extension project and how we can help you achieve a layout that's both functional and stunning.
Frequently Asked Questions
What is the ideal work triangle in a kitchen extension layout?
The work triangle connects your sink, hob, and fridge. Each side should measure between 1.2 and 2.7 metres for efficient movement. In an open-plan kitchen extension, maintain clear circulation space around these three points so you can move between them without obstruction. This reduces steps, improves workflow, and makes cooking safer and faster.
How much clearance space do I need for a kitchen island in my extension?
Allow a minimum of 1 metre on all sides of a kitchen island for circulation and appliance doors to open safely. If your extension is tight on space, a 900mm clearance can work, but 1.2 metres is ideal for two people to pass comfortably. The island itself should be at least 600mm deep and 1.2 metres long to be functional for prep work and seating.
What layout works best for a small kitchen extension?
For small spaces, galley layouts (two parallel runs of cabinetry) and L-shaped arrangements maximise efficiency. Consider a peninsula instead of a full island to save floor space. Built-in seating along one wall serves double duty as dining and storage. A side-return extension can wrap around an external wall, creating more usable length without expanding floor area significantly.
Can I use a free kitchen design planner to plan my extension layout?
Yes, free design planners help you visualise layout options, test appliance positions, and experiment with furniture arrangements. They work well for initial planning and communicating ideas to your architect. However, they cannot account for building regulations, structural constraints, services routing, or planning permission requirements. Use them as a starting point, then work with a professional to ensure your design is compliant and buildable.
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