Do you need planning permission for a loft conversion?

by | Conversions | 0 comments


Written by Dan Marks

Written by Dan Marks

Are you considering maximising your home’s space through a loft conversion? A common question in this scenario is: Do you need planning permission for a loft conversion? The answer isn’t always straightforward and depends on various factors. 

Typically, planning permission isn’t required if your loft conversion falls within the “permitted development rights” criteria, such as not exceeding specific volume limits and not including verandas or raised platforms. However, these rights can be removed by local planning authorities in some areas, making planning permission necessary. Therefore, you must always check with your local authority or seek professional advice to ensure your loft conversion complies with all regulations.

To learn more about whether you need planning permission or not for your next project, keep reading.

When do I need planning permission for a loft conversion?


Loft conversion permission is required under specific conditions. Here are various loft conversion types and their relation to planning permissions:

  • Rear Dormer Loft Conversion: A Rear Dormer Loft Conversion is a method of transformation that expands the available headroom and floor space within your loft. By extending the rear section of your roof, it generates an ample, box-like structure, potentially allowing for additions like an en-suite bathroom given the extra room it provides.

To maintain compliance with Permitted Development regulations in the UK, any included roof lights or windows in the design should not protrude more than 150mm beyond the plane of the existing roof slope.

Although most Rear Dormer Loft Conversions typically fall under Permitted Development rights and don’t require explicit planning permission, exceptions do exist. Particularly, homes situated in conservation areas or those classified as listed buildings may require planning permission.

  • Hip-to-Gable Loft Conversion: A Hip-to-Gable Loft Conversion involves extending your existing roof’s ridgeline to form a new vertical gable end, thereby significantly increasing the available space in your loft. This type of conversion is particularly suitable for semi-detached or end-of-terrace houses, fundamentally altering the sloping ‘hip’ roof design to a more spacious and practical ‘gable’ roof.

In terms of planning permissions and Permitted Development Rights in the UK, a Hip-to-Gable conversion generally doesn’t require planning permission, as long as the volume of the extension does not exceed 50 cubic metres for detached and semi-detached houses, or 40 cubic metres for terraced houses. It’s important to note that these limits include all previous roof space additions.

Nevertheless, while many Hip-to-Gable conversions can be done under Permitted Development Rights, there are exceptions, especially for houses in conservation areas or those classified as listed buildings, which may require explicit planning permission.

  • L-Shaped Loft Conversion: An L-shaped loft conversion is a popular choice for properties with a certain layout, typically Victorian and Edwardian terraced houses, where the rear of the property extends beyond the side of the house, creating an ‘L’ shape in the plan. This design offers generous space, often allowing for the addition of two rooms – perhaps a spacious master bedroom with en-suite and a smaller bedroom or study.

When utilizing this design under permitted development rules in the UK, you should adhere to a maximum limit of 50 cubic metres for detached and semi-detached houses, or 40 cubic metres for terraced houses. Keep in mind that this includes all prior roof space additions, so if you have previous extensions, they will count towards this limit.

  • Rooflight or Velux Conversion: An excellent choice for homes with a ridge height exceeding 250cm, Velux conversions are often the least costly and quickest to implement. They require no significant roof alterations, allowing for an extension of living space without planning permission. In most cases, Velux or “rooflight” conversions, where windows are installed flush with the existing roofline, generally do not require planning permission.

However, if your property is located in a designated area (like a conservation area, National Parks, or World Heritage Sites) or if it’s a listed building, you might need to obtain planning permission before carrying out a Velux conversion.

Regardless of the type of loft conversion you opt for, there are some general rules which would preclude you from building under permitted development rights. These are:

here are several circumstances where a loft conversion may not be able to operate under Permitted Development Rights, requiring planning permission instead. These include:

  1. Exceeding Volume Limits: If the conversion will increase the roof space by more than 50 cubic metres for detached and semi-detached houses or 40 cubic metres for terraced houses (including any previous roof space additions), planning permission will be needed.
  2. Design and Material Discrepancies: The materials used in the conversion should be similar in appearance to the existing house. If they are significantly different, planning permission may be required.
  3. Inclusion of Verandas, Balconies, or Raised Platforms: These are not covered by Permitted Development Rights and therefore require planning permission.
  4. Property Location: If your property is located in a designated area, such as a National Park, the Broads, an Area of Outstanding Natural Beauty, a conservation area, or a World Heritage Site, additional rules may apply, potentially necessitating planning permission.
  5. Listed Buildings: If your house is a listed building, it is likely you will need to apply for listed building consent, which is a different process from standard planning permission.
  6. Exceeding Roof Height: The highest part of the conversion should not be higher than the highest part of the existing roof. If it is, planning permission will be needed.
  7. Overhangs: Roof extensions should not overhang the outer face wall of the original house.
  8. Facing a Highway: If any part of the conversion would extend beyond the plane of the existing roof slope that fronts a highway, planning permission will be needed.
  9. Permitted Development Rights Removed: Some local planning authorities may have removed Permitted Development Rights in certain areas or for specific types of buildings, necessitating planning permission for any changes.


For a more detailed overview of the rules regarding these loft conversions, check the Planning Portal.


What are the loft conversion building regulations?

The journey of a loft extension involves more than just deciding on the design and material. Another key component of loft extension planning permission is building regulations. While these can vary by county, we’ve outlined a general guide to assist you:

  1. Structural Safety: A loft conversion must maintain the building’s structural stability. It’s crucial that the new floor is structurally sound and doesn’t overload the existing structure. For a thorough understanding, check out Loft Conversion Building Regs Part A.
  2. Fire Safety: Your loft conversion should include safe escape routes in case of fire, possibly involving fire-resistant doors or even a sprinkler system in certain situations. Approved Document B provides comprehensive information about this.
  3. Stairways: If your loft is destined to become a living space, it must include a safe and practical stairway. Take note of regulations regarding minimum headroom and maximum steepness. See Approved Document B for more details.
  4. Insulation: Ensure your loft meets energy efficiency standards, often necessitating specific levels of insulation in the walls, floor, and roof. Loft Conversion Building Regs Part L offers valuable guidance.
  5. Ventilation: Your loft conversion requires adequate ventilation to avoid condensation and mould. Loft Conversion Building Regs Part F provides the necessary guidelines.
  6. Windows: If your conversion includes dormer windows, they should harmonise with existing windows, and any side-facing windows need to be obscured-glazed and non-opening if they’re less than 1.7m from the floor.
  7. Electrics: All new electrical installations must comply with electrical safety building regulations, often needing a certified electrician’s oversight.
  8. Protected Species: If your loft is home to protected species, such as bats, you’ll need a licence from Natural England.

Always remember regulations can differ, so check with your local council to ensure the exact rules. 


How do I get planning permission?

Now you understand the fundamentals of planning permission, how do you get it? Typically, there are five steps: 

  1. Pre-application research and inquiries: The first step is doing your homework. Understand the guidelines and consult with experts as needed. Remember, loft conversion without planning permission can lead to unwanted issues.
  2. Preparation of detailed plans and documentation: Next, bring your vision to life on paper. Draft detailed plans and gather necessary documents. It’s not just about what you want but how it aligns with regulations.
  3. Submission of the application to the local planning authority (LPA): Once your plans are ready, submit your application. Reach out to your LPA via your local council, which you can find here.
  4. Navigating the review period: Patience is key during this time. Your application might undergo public consultations, a crucial stage in gaining approval.
  5. Understanding and responding to the decision: You’ll receive the verdict. If approved, celebrate! If not, understand the feedback and revise your application accordingly.


How much does planning permission cost?

A pivotal factor to account for is the cost of planning permission. For alterations or extensions to a single dwelling house or a flat, the standard charge for a full planning permission application is £206.

 However, you might be able to save a bit on planning permission and building costs. Our in-depth guide on “How to Save VAT on Building Work” teaches you ways to save VAT on building projects. 

Read more in our guide, How Much Does Planning Permission Cost.


How long does planning permission take, and how long does it last?

When you’re ready to create that dream attic space, understanding the timeline for planning permission is key. The approval process typically takes up to 8 weeks for straightforward cases, though it can extend to 13 weeks for more complex proposals.

Once you have the green light, planning permission for an attic conversion is valid for three years. This means construction work must begin within this period. For a more in-depth look at planning permission durations, take a moment to visit our guides on “How Long Does it Take To Get Planning Permission in the UK” and How Long Does Planning Permission Last?


What is the four-year rule?

 This rule in the UK planning law allows homeowners to apply for a Certificate of Lawfulness after using their buildings or land continuously for four years without necessary planning permission.

 In essence, this rule grants immunity against enforcement action for unauthorised development if it has existed without challenge for four continuous years. The purpose is to provide a time limit on the period within which local authorities can take enforcement action against breaches of planning control.

 The Four-Year Rule can provide peace of mind to homeowners and developers who have undertaken work without the required planning permissions, provided the development has been unchallenged for the stipulated duration.


In conclusion, understanding whether you need planning permission for a loft conversion can be a complex process as it often depends on various factors such as the type of conversion, the specific characteristics of your property, and its location. While many loft conversions can be completed under Permitted Development Rights, there are many exceptions to these rules, particularly for properties in designated areas or for certain design elements like balconies.

Remember that exceeding the limits and conditions of Permitted Development Rights or failing to obtain required planning permission can lead to complications and penalties. Therefore, it’s crucial to be aware of these factors and always seek professional advice before embarking on your loft conversion project.

Consulting with your local planning authority or a professional advisor ensures your project adheres to the latest regulations, thus avoiding potential legal issues and making sure your conversion enhances your home’s value and usability.

As with any home improvement, thorough planning and understanding of the regulations involved are key to a successful loft conversion. Happy planning, and here’s to creating a fantastic new space in your home!

loft conversion

Other FAQ’s

Can I build my loft conversion under Permitted Development rules?

Yes, in many cases, you can build your loft conversion under Permitted Development rules. However, this depends on factors such as the volume and height of the conversion, the materials used, the property's location, and whether your local authority has removed Permitted Development Rights in your area. It's always recommended to consult with your local planning authority or a professional advisor to confirm.

Do I need a planning consultant if considering a loft conversion?

The need for a planning consultant largely depends on the complexities involved in your loft conversion project. While a consultant can aid you in comprehending the planning process and ensuring compliance with relevant laws and regulations, you might not require one for straightforward renovations or minor alterations to your home's structure.

Do I need planning permission when adding a balcony to a loft conversion?

Yes - adding a balcony to a loft conversion typically requires planning permission. Balconies, verandas, and raised platforms do not usually fall under Permitted Development Rights. It's important to consult with your local planning authority to understand the specific requirements for your property and location.

Do you need to apply for permitted development?

Should you desire to make alterations to your home, such as a loft conversion, you might need to apply for permitted development. This form of planning permission allows certain changes without needing comprehensive planning permission. You can determine if you must apply for permitted development through the government's planning portal.

Can I get confirmation that I do not need planning permission?

Yes, confirming whether planning permission is not required for your project is possible. However, it's always advisable to consult your local planning authority for the highest assurance.

Do I need planning permission for a dormer loft conversion?

Whether you need planning permission for a dormer loft conversion depends on various factors, including the size and position of the dormer and the type of property you have. If the dormer loft conversion meets certain conditions, it may fall under Permitted Development Rights, which means that formal planning permission isn't required.

These conditions typically include restrictions such as the dormer not exceeding the highest part of the existing roof, not extending beyond the plane of the existing roof slope at the front of the house, and being set as far back as possible, at least 20cm from the original eaves. The materials used should also match the existing house.

However, if the property is in a designated area such as a conservation area or a listed building, planning permission may be required regardless of the dormer's size and position. As these regulations can change and may vary by location, it's always best to consult with your local planning authority or a professional advisor.

Stay Two Steps Ahead

Sign up for news, views and insights.
One email, twice a year.

You May Also Like…

No Results Found

The page you requested could not be found. Try refining your search, or use the navigation above to locate the post.

Let's Create Your Home's Next Chapter

Wondering what comes next?

Fill in the form below with your project details and we'll respond in 1-2 days.

13 + 14 =

Book a 45 minute video call or face to face meeting

View and book here