House Extensions
London & Hertfordshire
Explore rear, side, double-storey and wrap-around extension options. Discuss the property, proposed scope, access, planning route and specialist requirements with TCM.
The Most Popular Way to
Add Space & Value
A house extension is a permanent structure added to an existing residential property to increase its floor area. Unlike a loft conversion or basement conversion, a house extension typically extends the footprint of the property outwards — to the rear, side, or both — creating new ground-floor or multi-storey living space.
For homeowners in London and Hertfordshire, a house extension is often the most practical alternative to moving — avoiding stamp duty, estate agent fees, and the upheaval of relocation, while creating a home that is precisely tailored to your family's needs.
TCM can manage building work directly and, where appropriate, coordinate the specialist contractors and professional disciplines required for the project. The delivery arrangements depend on the individual scope.
Which Extension Is Right for You?
Rear House Extensions
A rear extension is the most common type of house extension in London and Hertfordshire. It extends the back of your home into the garden, typically creating a larger kitchen, open-plan kitchen-diner, or additional living space. Under Permitted Development rights, a single-storey rear extension can extend up to 3 metres on a semi-detached or terraced house, and up to 4 metres on a detached house — without planning permission.
How We Deliver Your Extension
Project Enquiry
Discuss the property, proposed scope, access and any known planning or specialist requirements.
Design & Planning
The design and planning route depends on the property and scope. Appropriate professional input may be required.
Structural Engineering
Structural alterations require appropriate competent professional input and the relevant regulatory route.
Scope and Commercial Terms
Confirm the agreed scope, inclusions, exclusions, VAT, allowances and change process before work begins.
Construction
TCM can deliver building work directly and coordinate specialist contractors and professional disciplines where appropriate.
Finishing & Handover
Agree inspection points, handover information and any remaining specialist requirements for the project.
Do You Need Planning
Permission?
Many house extensions in England can be built under Permitted Development rights, meaning no formal planning application is required. However, the rules are complex and depend on your property type, location, and the size of the proposed extension.
The appropriate planning and Building Regulations route depends on the property and proposed work. TCM can coordinate the professional disciplines required for the project where appropriate.
House Extension Scope Guide
The appropriate scope depends on the property, proposed work, access, design, ground conditions, planning route and specialist requirements.
| Extension Type | Property and Access | Scope | Programme | Planning |
|---|---|---|---|---|
| Single-Storey Rear | Confirm site conditions | Scope-dependent | Project-dependent | Confirm route |
| Side Return | Confirm access | Scope-dependent | Project-dependent | Confirm route |
| Double Storey | Confirm structural input | Scope-dependent | Project-dependent | Confirm route |
| Wrap-Around | Confirm planning requirements | Scope-dependent | Project-dependent | Confirm route |
Establish the applicable planning route, scope, inclusions, exclusions, VAT, allowances and change process for the individual project.
Questions to Resolve Before Work Begins
Establish the scope, access, design information, planning route, structural requirements and commercial terms before building work is arranged.
| Extension Type | Property | Scope | Programme | Specialist Input |
|---|---|---|---|---|
| Single-Storey Rear | Access and ground conditions | Define inclusions | Agree milestones | Planning and trades |
| Side Return | Neighbouring property considerations | Define inclusions | Agree milestones | Planning and trades |
| Double Storey | Structural requirements | Define inclusions | Agree milestones | Structural professional |
| Wrap-Around | Planning and access considerations | Define inclusions | Agree milestones | Planning and trades |
Scope Details Matter
Ground conditions, drainage, trees, neighbouring structures, access and the required foundations can affect the proposed scope. Identify the relevant surveys, investigations and professional input before the work is arranged.
Party-wall and planning requirements should be considered early where they may apply. Obtain the appropriate independent professional advice for the individual property and proposed work.
The TCM Difference
A house extension requires an agreed scope, clear responsibilities and the appropriate professional and specialist input.
TCM can manage building work directly and coordinate specialist contractors and professional disciplines where appropriate.
Confirm inclusions, exclusions, VAT, allowances and the change process before work begins.
Agree roles, communication arrangements, inspection points and handover information for the project.
Establish the appropriate planning, Building Regulations and party-wall route for the property and proposed work.
Structural and other regulated work must follow the appropriate competent, registered or licensed specialist route.
Before You Commit
Check the proposed scope, relevant approvals, specialist responsibilities, access arrangements and commercial terms before building work begins.
Ready to Discuss Your Project?
Contact TCM to discuss the property, proposed scope, access and any known planning or specialist requirements.
You love your home, but you're running out of room. Maybe your family's growing, or you just need that extra living space you've always wanted. Moving house can be a huge headache, with all the costs and disruption. What if you could create the perfect new space right where you are? That's exactly what a house extension offers. It's about expanding your existing property, whether that's a single-storey rear addition for a bigger kitchen, a double-storey extension for extra bedrooms, a clever side return, or a comprehensive wrap-around. We also handle extensions over garages, making the most of every inch. An extension isn't just about adding square footage; it's about transforming your daily life. Imagine a brighter, more functional kitchen, a dedicated home office, or a spacious new master suite. It's an investment that significantly boosts your property's value and, more importantly, your quality of life.
You're starting to feel the squeeze at home, aren't you? Maybe the kids need more space, or you're dreaming of a bigger kitchen for entertaining. You know something needs to change to make your home work better for you, but you're not quite sure what the best path forward is yet.
What You Need to Know
Design and Planning
The design and planning route depends on the property, proposed scope and relevant local requirements. Appropriate professional input may be required.
Structural Requirements
Structural alterations require the appropriate competent professional input and the relevant regulatory route.
Project Scope
Confirm the proposed work, inclusions, exclusions, VAT, allowances and change process before work begins.
Project Coordination
TCM can manage building work directly and coordinate specialist contractors and professional disciplines where appropriate.
Everything Else You Should Know
Understanding House Extension Costs
How much does an extension really cost? It's a common question, and the answer depends on several factors like size, materials, and complexity. We provide detailed, transparent quotes, breaking down all expenses so you can make informed decisions. We'll discuss your budget early on to ensure your dream extension is also financially viable.
Navigating Planning & Regulations
Do you need planning permission, or does your project fall under Permitted Development? Understanding the rules can feel overwhelming. We're experts in local regulations for Borehamwood and Hertfordshire, guiding you through the entire process to ensure your extension complies with all legal requirements.
Extension vs. Moving: What's Right for You?
You're weighing up your options: extend or move? Extending your home can save you stamp duty, solicitor fees, and the stress of finding a new property. It allows you to create a bespoke space tailored to your exact needs, often at a lower overall cost than relocating.
Common Extension Mistakes to Avoid
Building an extension is a big undertaking, and it's easy to overlook crucial details. We help you avoid common pitfalls like underestimating budgets, neglecting proper planning, or choosing the wrong builder. Our expertise ensures a smooth process and a high-quality finish.
House Extension FAQs
Discuss Your Extension Project
Call us or submit an enquiry to discuss the property, proposed work, access and any known specialist requirements.
Explore House Extensions Location Pages
TCM Building & Maintenance is based in Borehamwood, Hertfordshire. The individual location pages provide project information for each place. Discuss your location, scope and access requirements directly before making arrangements.
TCM Building & Maintenance is based in Borehamwood, Hertfordshire.
Explore the Radlett location page.
Explore the Bushey location page.
Explore the Potters Bar location page.
Explore the Watford location page.
Explore the St Albans location page.
Explore the Hatfield location page.
Explore the Welwyn Garden City location page.
Explore the Barnet location page.
Explore the Edgware location page.
Explore the Stanmore location page.
Discuss your project location with TCM: Call 07305 121634 .