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info@fixiz.co.uk
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When your family outgrows your home but you love the neighbourhood, a house extension is the smart alternative to moving. Extensions add living space, increase property value, and let you design exactly the home you need. At Fixiz, we have designed and built extensions across London for over a decade. Here are five stunning house extension ideas that are trending in 2026.
1. Open-Plan Kitchen with Bifold Doors
The single most requested house extension in the UK is a rear kitchen extension with floor-to-ceiling bifold or sliding doors that open onto the garden. This creates a seamless indoor-outdoor living experience that floods the space with natural light. A large kitchen island, integrated appliances, and underfloor heating complete the picture. Under permitted development, you can extend up to 6 metres from the rear wall of a semi-detached house (8 metres for detached) without planning permission, though a prior approval process may be needed for larger extensions. Budget from £30,000 to £60,000 depending on size and specification.
2. Double-Storey Side Extension
If you have wasted space down the side of your house, a double-storey side extension can add both a ground-floor living area and an extra bedroom or bathroom above. This is one of the most effective ways to maximise your footprint. You will typically need planning permission for a double-storey extension, and the design must respect the character of your street. Costs range from £40,000 to £80,000, but the value added to your property often exceeds the build cost. Fixiz house extension specialists handle design, planning, and construction under one roof.
3. Glass Orangery Living Room
For homeowners who want something more elegant than a standard conservatory, a glass orangery extension offers the best of both worlds: the light and openness of a conservatory with the solidity and insulation of a traditional brick extension. A lantern roof, brick pillars, and large glass panels create a bright living or dining space that can be used year-round. Modern orangeries with proper insulation and underfloor heating maintain comfortable temperatures in every season. Expect to invest between £25,000 and £50,000 for a quality orangery extension.
4. Family Games Room and Utility Space
A wraparound extension that covers both the rear and side of your property can create enough space for a dedicated family games room complete with a pool table, home bar area, and comfortable seating, alongside a practical utility room with laundry facilities, extra storage, and a secondary entrance from the garden. This type of extension works particularly well for period properties where the original kitchen is small and there is garden space to extend into. Costs for a wraparound extension typically start at £50,000 and can reach £100,000 for larger or more complex builds.
5. Home Library and Office Extension
With remote and hybrid working now standard, a purpose-built home office extension is a wise investment. Combine it with a home library featuring floor-to-ceiling shelving, a reading corner, and quality task lighting for a space that inspires productivity and relaxation. A single-storey rear or side extension with a flat green roof, large picture windows, and acoustic insulation creates a peaceful working environment separate from the main household. This type of extension typically costs between £20,000 and £40,000 and adds significant appeal to your property.
How Much Does a House Extension Cost in the UK?
House extension costs vary widely depending on location, size, and specification. As a general guide for London and the South East: single-storey rear extensions cost £1,500 to £2,500 per square metre, double-storey extensions cost £1,200 to £2,000 per square metre, and wraparound or basement extensions command a premium. Always factor in professional fees for architects, structural engineers, and building control. Fixiz provides all-inclusive project quotes so there are no surprises.
Do You Need Planning Permission for a House Extension?
Many single-storey extensions fall under permitted development rights, meaning no formal planning permission is required. However, double-storey extensions, extensions to flats, and properties in conservation areas or Article 4 zones almost always need planning approval. Regardless of planning status, all extensions require building regulations approval and typically a party wall agreement if you share a boundary wall. Fixiz manages the entire planning and building control process from start to finish.
Why Choose Fixiz for Your House Extension?
Fixiz brings together architectural design, structural engineering, and expert construction under one company. We have completed house extensions of every size and style across London, always delivering on time and on budget. From the first sketch to the final coat of paint, you deal with one team who genuinely cares about your home. Contact Fixiz today for a free house extension consultation and quote.