Get Rapid Plans Ltd

Architectural Services

Phone: +44 7507 665812


Get Rapid Plans Ltd

Architectural Services

Phone: 07507 665812


Adding an extension to your house is a fantastic way to gain more space without the hassle of moving. But before you get stuck in picturing that dream kitchen extension, it’s crucial to understand the regulations around house extensions in the UK.

There are two main paths you can take: permitted development and planning permission.

Permitted Development vs. Planning Permission:

Most importantly, understand the two main approaches:

  • Permitted Development: Allows smaller extensions without formal planning permission. It’s faster and cheaper but has limitations.
  • Planning Permission: Needed for larger or more complex extensions. It takes longer and costs more, but offers more flexibility.
Rules for House Extensions

Permitted Development: The Simpler Option

Permitted development allows you to complete certain extension projects without needing formal planning permission from your local council. This is a much faster and cheaper process, but it comes with limitations. Here’s what you can generally do under permitted development:

  • Single-storey rear extensions: Up to 4 metres for detached houses and 3 metres for other property types, with a maximum height of 4 metres.
  • Single-storey side extensions: No more than half the width of your house and a maximum height of 4 metres. However, side extensions are not permitted on designated land.

There are additional restrictions like using similar materials to your existing house and staying clear of certain boundaries. It’s always best to check the government’s planning portal to see the full details for permitted development: [planning portal gov uk house extensions].

Planning Permission: For More Flexibility

If your dream extension doesn’t fit within permitted development guidelines, you’ll need to apply for planning permission from your local council. This process takes longer and involves submitting detailed plans and drawings. However, it gives you more freedom for:

  • Larger extensions: Want a double-storey extension or something that stretches further than permitted development allows? Planning permission is the way to go.
  • More complex designs: Envisioning a balcony or a unique roof design? You’ll likely need planning permission to make it happen.

Loft Conversions:

  • Permitted development is possible if:
    • Creates less than 40 cubic metres of additional space (terraced) or 50 cubic metres (detached/semi-detached).
    • Doesn’t extend beyond the existing roof slope facing the street.
    • Doesn’t exceed the highest point of the existing roof.
    • Uses similar materials to the existing house.

Always check the full rules on the Planning Portal ([planning portal gov uk house extensions]).

Single Storey Extensions:

  • Up to 4 metres for detached houses, 3 metres for others (max height 4 metres) under permitted development.
  • Additional limitations may apply depending on location and property type.

Double Storey Extensions:

  • Almost always require planning permission due to size and impact.

Front House Extensions:

  • Permitted development is unlikely due to visual impact. Planning permission usually needed.

Rear House Extensions:

  • Most common extension type.
  • Permitted development may apply for single-storey extensions within size limits.
  • Larger extensions require planning permission.

Side House Extensions:

  • Permitted development may apply for single-storey extensions following general allowances (not on designated land).
  • Extensions exceeding these limits or affecting neighbours likely need planning permission.

Garage Extensions:

  • Converting a garage may fall under permitted development if it meets size limits and regulations.
  • Some structural changes might require planning permission.

From Dream to Reality: Your Complete House Extension Checklist

Extending your house can be a fantastic way to gain valuable space and enhance your lifestyle. But before the demolition crew arrives, there’s important groundwork to be laid. This checklist will guide you through the key considerations to ensure a smooth and successful extension project.

Defining Your Needs & Goals:

  • Why extend? Be clear on your reasons. Do you need a dedicated workspace, a larger kitchen, or an extra bedroom?
  • Future-proofing: Consider how your needs might evolve over time. Will the extension accommodate potential changes in family size or lifestyle?
  • Wish list vs. reality: Create a wish list of features, but be realistic about your budget and space limitations.

Planning & Permissions:

  • Permitted development vs. planning permission: Understand the difference and determine which applies to your project.
  • Consult a professional: An architect or architectural firm can help create a feasible design and navigate planning regulations.
  • Building regulations: Ensure your extension complies with all safety and energy efficiency standards.

Budget & Costs:

  • Set a realistic budget: Factor in not just construction costs, but also architect fees, planning application fees, and potential building regulation costs.
  • Get quotes: Obtain quotes from several builders to compare prices and find the best fit for your project.
  • Contingency plan: Allocate a buffer in your budget for unexpected costs that may arise during construction.

Living Arrangements & Logistics:

  • Impact on your life: Consider how the construction will affect your daily routine. Will you need to find temporary living arrangements?
  • Storage solutions: Where will you keep furniture and belongings during construction?
  • Access and disruption: Discuss access for builders and deliveries with your neighbours. Be prepared for potential noise and disruption.

Design & Functionality:

  • Light and space: Maximize natural light and create a sense of flow in your extended space.
  • Storage solutions: Integrate efficient storage solutions to keep your new space organized.
  • Material choices: Select materials that complement your existing house and are suitable for the extension’s purpose.

Communication & Management:

  • Clear communication: Maintain clear communication with your builder, architect, and neighbours throughout the project.
  • Regular inspections: Schedule regular inspections to ensure the work aligns with plans and building regulations.

Project management: Decide if you’ll manage the project yourself or hire a project manager to oversee the process.

The Role of Architectural Firms in Professional Guidance for Building Extensions Projects

Adding an extension to your home can be an exciting time, but it’s also a complex undertaking. An architectural firm can be your invaluable partner throughout the entire process, ensuring your project runs smoothly and delivers the results you envision. Here’s how:

Expert Guidance and Feasibility Studies:

  • Maximizing Potential: Architects possess the expertise to assess your property and maximize the space you gain from your extension. They’ll consider factors like sunlight, existing structures, and local regulations to ensure an optimal design.
  • Feasibility Assessment: An architect can conduct a feasibility study to identify potential challenges and opportunities. This helps you make informed decisions about the scope and budget of your project.

Creative Design and Planning:

  • Transforming Your Vision: Architects bring creativity and technical skill to the table. They’ll translate your vision for the extension into a functional and aesthetically pleasing design that seamlessly integrates with your existing home.
  • Planning Expertise: Navigating planning regulations can be daunting. Architects have the knowledge and experience to handle the planning application process, ensuring your project complies with all necessary regulations.

Technical Expertise and Project Management:

  • Building Regulations: Architects ensure your extension adheres to all building regulations regarding safety, structural integrity, and energy efficiency.
  • Project Management: Many architectural firms offer project management services, overseeing the entire construction process. This includes coordinating with builders, engineers, and other specialists, keeping you informed every step of the way.

Additional Benefits:

  • Cost Savings: While there’s an initial investment in architectural services, an architect’s expertise can help you avoid costly mistakes during construction. They can also help you optimize your budget by suggesting cost-effective materials and solutions.
  • Peace of Mind: Knowing your project is in the hands of qualified professionals gives you peace of mind. Architects can address any concerns you have and ensure the project progresses smoothly.

Choosing the Right Architecture firm : 

  • Look for experience with extensions: Ensure the firm has experience working on projects similar to yours.
  • Communication style: Find an architectural consultant who listens to your needs and communicates effectively.
  • Project fees: Get quotes from several firms and compare their fees and service packages.

    Key Points to Consider
  • Party Wall Agreements: If your extension affects a shared wall with a neighbour, you’ll need a party wall agreement in place before construction begins. A party wall surveyor can help with this process.
  • Building Regulations: Regardless of permitted development or planning permission, your extension must comply with building regulations regarding safety and energy efficiency.

Getting Started on Your Extension Journey

Thinking about extending your home? Here are some next steps:

  • Check the planning portal: See if your project falls under permitted development.
  • Talk to a builder or architect: They can advise on the feasibility of your plans and guide you through the permission process.
  • Contact your local council’s planning department: Discuss your project and any concerns you may have.