What is a good size kitchen extension? : Homeowner’s Guide

by | 14th May 2025 | KT5 Construction News | 0 comments

Open plan rear kitchen extension with island and pitched roof

Wondering what is a good size kitchen extension for your home? You’re not alone. Whether you’re dreaming of a side return kitchen extension or a full-width rear kitchen extension, the ideal size depends on your property, lifestyle, and local planning regulations. At KT5 Construction, expert extension builders in Surrey and London, we specialise in delivering expertly crafted kitchen extensions that maximise value, space, and comfort.

From open-plan kitchens and pitched roof designs to glazed orangery extensions, this guide will help you plan the perfect extension tailored to your needs.

How Big Should a Kitchen Extension Be?

A typical kitchen extension can range from 15m² to 30m², though larger rear house extensions can exceed 40m², especially in detached properties. Here’s how to assess your space:

Factors That Influence Size

    • Property type: Detached homes have more flexibility than terraced or semi-detached properties.

    • Permitted development rights: Single-storey rear extensions may not require full planning permission if within certain size limits.

    • Budget: The kitchen extension cost often determines the final dimensions.

    • Use case: Want a kitchen diner or space for a kitchen island? You’ll need more square metres.

Common Extension Sizes

    • Side return kitchen extension: ~10–15m²

    • Single-storey rear kitchen extension: ~15–30m²

    • Wraparound house extension: ~30–50m²

🛠️ KT5 Construction offers a free on-site consultation to help determine the optimal size for your space.

Planning Permission for Kitchen Extensions

You may not need formal permission if your plans meet permitted development rear extension criteria:

Permitted Development Limits

    • Extend up to 6m (semi-detached) or 8m (detached) homes to the rear

    • Max eaves height of 3m

    • Extension must not exceed 50% of total garden space

If your design exceeds these limits or is in a conservation area, you’ll need planning permission for rear extension or side return.

Why do homeowners choose KT5 Construction as their Kitchen Extension Builder?

    • Trusted specialists in the kitchen extension.

    • Full service: From planning permission to building control.

    • Local expertise across London and Surrey.

    • 25+ years of proven experience.

Let’s talk today—your dream space is closer than you think.

Building Regulations for Kitchen Extensions

Regardless of size, all house extensions must comply with UK building regulations, covering:

    • Structural stability and foundations

    • Energy efficiency (Part L)

    • Ventilation and fire safety

    • Electrical and plumbing systems

KT5 Construction handles building control submissions, liaising with inspectors to ensure full compliance.

Popular Kitchen Extension Types

Rear Kitchen Extensions

Great for expanding towards the garden. Can be combined with bi-fold doors for seamless indoor-outdoor living.

Side Return Kitchen Extensions

Perfect for Victorian and Edwardian terraces. Adds valuable space without compromising the garden.

Wraparound Kitchen Extensions

Combine side and rear for a large open-plan kitchen. Ideal for kitchen diner ideas and broken-plan kitchen layouts.

Flat or Pitched Roof Kitchen Extensions

    • Flat roof kitchen extension: Contemporary, cost-effective.

    • Pitched roof kitchen extension: Traditional, allows for skylight kitchen extension options.

Glazed and Orangery Extensions

    • Orangery kitchen extension: Elegant with partial glazing.

    • Kitchen conservatory extension: Maximises light and garden views.

    • Kitchen extension with skylights: Boosts light penetration and value.

Design Considerations and Layout Planning

At KT5, we focus on kitchen layout planning to ensure practical and beautiful outcomes:

    • Zone spaces: Cooking, dining, entertaining

    • Use natural light: Use clerestory windows or roof lights

    • Include heating/electrics: Plan early to avoid surprises

Kitchen Diner Ideas & Island Layouts

    • Add a kitchen island for prep and storage

    • Include a dining area for family meals

    • Create a broken-plan kitchen for noise control and separation

FAQs: Answering Your Extension Queries

Q: How do I finance a kitchen extension?

Explore options like:

    • Savings or remortgaging

    • Unsecured loans

    • Home renovation platform funding tools

Q: What’s the typical kitchen extension timeline?

    • 8–16 weeks for construction

    • Up to 12 months including planning and approvals

Q: Does a kitchen extension add value?

Yes! Well-designed kitchen extensions can boost property value by 10–20%.

Call to Action

Ready to plan your kitchen extension? Contact KT5 Construction today for expert advice, a free quote, and an on-site consultation tailored to your home.