House Extensions in Hounslow
Home » House Extensions London »
At Bigness Group, we design and build high-quality house extensions in Hounslow, helping homeowners create stylish, functional, and long-lasting spaces.
From period terraces in Chiswick and Isleworth to suburban homes in Feltham and Hounslow Central, we specialise in extensions that add light, space, and value — built with precision and care.
We handle the full journey — from concept and planning to construction and finish — ensuring your project is managed professionally and delivered on time.
Design and Build Services
Our Hounslow design-and-build team provides a complete end-to-end service:
-
Full measured survey, design concepts, and 3D visuals
-
Planning permission and permitted development management via Hounslow Council
-
Structural design, engineering, and Building Control compliance
-
Kitchen, living, and interior integration
-
Dedicated project management with milestone reporting
With one team responsible for every stage, we ensure clarity, speed, and a flawless finish — all under the trusted Bigness name.
Types of Extensions We Build
We construct all major types of house extensions across Hillingdon, including:
• Glass Box Extensions – Contemporary architectural additions.
• Modern House Extensions – Sleek designs that fuse architecture and innovation.
• Single-Storey Extensions – Expand your kitchen, dining, or family area with natural light.
• Double-Storey Extensions – Add bedrooms or offices above while extending living space below.
• Side-Return Extensions – Perfect for semi-detached and terraced homes.
• Rear Extensions – Create spacious, modern garden-facing living areas.
• Wrap-Around Extensions – Combine side and rear builds for full open-plan layouts.
• Conservatories & Orangeries – Glazed extensions for all-season comfort.
• Loft & Garage Conversions with Extensions – Add new rooms vertically or repurpose existing structures.
Construction Standards
Every Bigness project in Hounslow follows our proven six-stage build process:
-
Groundworks & Foundations – Engineered to local site conditions and drainage.
-
Structural Framework – RSJs and beams for strength and open layouts.
-
Walls & Roofs – Brick match, render, or zinc finish with full insulation.
-
Windows & Glazing – Energy-efficient systems meeting all current regulations.
-
Interior Fit-Out – Plumbing, electrics, plastering, flooring, and joinery.
-
Final Inspection & Warranty – Building Control approval and structural guarantee.
Local Knowledge
We’re highly experienced with Hounslow Council’s planning and building requirements, including conservation areas around Chiswick and Isleworth.
Our familiarity with local architecture and regulations ensures faster approvals and designs that complement the borough’s unique style.
Costs and Financing
Every extension is unique, but here’s a general guide:
| Type | Typical Cost Range (2025) |
|---|---|
| Single-Storey Extension | £45,000 – £85,000 |
| Double-Storey Extension | £75,000 – £130,000 |
| Wrap-Around Extension | £90,000 – £160,000 |
| Side-Return Extension | £40,000 – £75,000 |
💡 Factors include size, materials, access, and specification level.
We provide transparent quotes with detailed breakdowns and stage payments.
Financing options may be available through our partner lenders for eligible clients — ask our team for guidance on home improvement financing.
The Process
1. Consultation & Site Visit – We meet you on-site to discuss ideas, goals, and feasibility.
2. Design & Planning – We prepare drawings, handle permissions, and finalise the budget.
3. Construction Phase – Our project manager oversees all work, ensuring safety and communication at every step.
4. Completion & Aftercare – Once finished, we conduct final inspections and provide warranty documentation.
We also offer optional maintenance plans to keep your new space performing at its best.
Why Choose Bigness Group
-
Local expertise: in-depth knowledge of Hounslow’s planning regulations.
-
Full-service delivery: from design and permissions to construction and finish.
-
Certified professionals: compliant with all Building Regulations.
-
Transparent costs: itemised, fixed-price quotes with staged payments.
-
Trusted reputation: a proven record across West and South West London.
With Bigness Group, your extension is more than an addition — it’s a transformation.
FAQ
Do I need planning permission for an extension in Hounslow?
Many extensions fall under permitted development, but larger or conservation-area properties require approval. We handle all applications and drawings for you.
How long does construction take?
Most single-storey projects take 8–14 weeks, while double-storey or complex builds take 12–20 weeks.
Can you match my home’s materials and style?
Yes — we source matching bricks, tiles, and finishes for a perfect visual blend.
Do you offer full interior fit-outs?
Absolutely. We can include kitchens, lighting, flooring, and full interior finishes.
Our Recent Projects in Hounslow
Our recent work in Hounslow includes a wrap-around kitchen extension in Isleworth, a modern double-storey build in Feltham, and a side-return design in Chiswick.
Each project reflects our dedication to precision, quality, and thoughtful design — built to enhance both your home and your everyday life.
House Extensions in London by Borough
Bigness Group designs and builds bespoke house extensions across all London boroughs, including Hounslow and West London’s surrounding areas. Our experience with local councils and property styles ensures smooth approvals and flawless craftsmanship on every project.
Barking and Dagenham / Barnet / Bexley / Brent / Bromley / Camden / Croydon / Ealing / Enfield / Greenwich / Hackney / Hammersmith and Fulham / Haringey / Harrow / Havering / Hillingdon / Hounslow / Islington / Kensington and Chelsea / Kingston upon Thames / Lambeth / Lewisham / Merton / Newham / Redbridge / Richmond upon Thames / Southwark / Sutton / Tower Hamlets / Waltham Forest / Wandsworth / Westminster
Bigness Insights
Smarter building, shared knowledge.
Are you a homeowner planning to give your property a makeover, or a property investor looking to increase the value of your rental portfolio? Perhaps you want to transform an outdated property into a modern, energy-efficient home that appeals to buyers or tenants. This complete guide to property refurbishment in the UK walks you through […]
For decades, most buildings have been designed to achieve one main goal:get approved, get built, get handed over. What happens after that is often an afterthought. Maintenance issues.Energy inefficiency.Costly upgrades.Design decisions that don’t age well. As regulations tighten, energy costs rise, and expectations change, this way of building is no longer enough. The future belongs […]
Choosing to build a timber structure isn’t just about adding something to your property—it’s about creating a space that breathes with purpose. Whether it’s a peaceful summerhouse for quiet reflection, a sturdy garage to protect what you treasure, a playful nook for childhood memories, or a custom retreat for a beloved pet, timber buildings carry […]
In the heart of a city that never sleeps, where history whispers from brick and modernity soars in glass and steel, your property is more than just an asset—it’s a legacy. It’s the roof over your family, the foundation of your business, the culmination of a lifetime of work. A smart owner understands that protecting […]
Is your building an asset or a liability? For many business owners and property managers, the answer depends on one critical factor: a consistent, professional building maintenance strategy. A well-maintained building is more than just a pleasant place to work; it’s a safe, efficient, and valuable asset. On the other hand, deferred maintenance can lead […]
At Bigness Group, we are proud to launch our official website and open the doors to a new chapter in construction and property services across London. Our vision is simple: small enough to listen, big enough to deliver. This means we dedicate the same care and attention to small maintenance jobs as we do to […]