At Bigger Living Lofts, we specialise in turning under-utilised roof space into beautiful, functional rooms that enhance lifestyles and add lasting value to homes across Kent and Southeast London. Permitted development loft conversion plays a central role in many projects because it allows homeowners to expand upwards with minimum planning hurdles when specific conditions are met. 

Call 01732 523199 or email info@biggerlivinglofts.com to get started today. 

In this guide, we explain rules, benefits and limitations of permitted development loft conversion so you can make confident decisions about transforming your home.

What Is a Permitted Development Loft Conversion? 

A permitted development loft conversion is a type of roof extension that does not normally require formal planning permission because it fits within rights granted under the UK’s General Permitted Development Order, subject to limits and conditions. This makes it a popular route for homeowners who want to enhance living space without a planning application.  

At Bigger Living Lofts, we help clients understand whether their property qualifies for this route, and when planning permission may still be necessary.  

Permitted Development Loft Conversion Rules 

To take advantage of a permitted development loft conversion, your project must comply with several key rules, ensuring that it stays within legal boundaries and avoids planning delays. 

Volume Limits and Roof Conditions 

Under permitted development rules you can increase roof space without planning permission provided: 

  • Additional volume does not exceed 40 cubic metres for terraced homes.  
  • It stays within 50 cubic metres for detached or semi-detached dwellings.  
  • The new construction does not extend beyond the original roof’s highest plane.  

These conditions safeguard the home’s appearance and ensure developments remain proportionate to the original structure.  

Materials and External Features 

Materials used must match those of the existing house to maintain visual harmony.  

Additionally: 

  • Verandas and raised platforms are not permitted without planning.  
  • Side-facing windows must be obscure glazed and positioned 1.7 metres above floor level to prevent overlooking.  

When these criteria are met, the conversion is treated as permitted development, eliminating the need for a planning application. However, if your project doesn’t meet them, then planning permission will be required.  

Permitted Development Loft Conversion Limitations 

Understanding the limitations of permitted development loft conversion is equally important as appreciating its benefits. These constraints can affect what you can build and whether it suits your vision: 

Conservation Areas and Special Designations 

Properties in conservation areas, listed buildings or sites with Article 4 directions often lose permitted development rights entirely. In those circumstances, planning permission will be mandatory, regardless of your design’s scale. 

Previous Extensions or Roof Alterations 

If previous owners have already expanded your roof under permitted development, your future volume allowance will be reduced accordingly, possibly pushing your project outside PD eligibility.  

Appearance and Oversight 

The need for matching materials and regulated window placement means your design may be more conservative than a fully planned application route. This helps preserve neighbourhood character but limits creative freedom.  

In such cases, we always recommend consulting with planning professionals like our team early so you can choose the best route for your specific property. 

Benefits of Permitted Development Loft Conversion

While the rules and limitations are important, the advantages of choosing a permitted development loft conversion are significant and often pivotal in home improvement projects. 

Faster Turnaround Without Planning Delays 

One of the biggest advantages is that you can often avoid the time-consuming planning application process, which can delay works by weeks or months. This mean you can start building sooner and enjoy your new space with less delay. 

Cost Savings 

Without the need for planning fees, professional planning applications, and prolonged administrative work, the overall cost of your project is often reduced. This makes permitted development a cost-efficient way to gain extra liveable area. 

Increased Property Value 

Loft conversions generally add value to a property by creating functional space such as a master suite, guest room or a home office. Even under permitted development, these enhancements are attractive to future buyers when done well.  

Less Bureaucracy, More Certainty 

With a permitted development loft conversion, the rules are clear and transparent, giving you a solid framework for what is allowed without formal consent as long as you follow the limits. That translates into less stress and more certainty throughout your project. 

 

When Planning Permission Is Still Needed 

Although many loft conversions will fall under permitted development rights, there are specific situations in which formal planning permission is still required. 

Significant Alterations to Roof Structure 

If your design involves substantial changes to the roof shape or massing, such as a full mansard conversion, it’s likely to be outside PD rights.  

Listed or Protected Properties 

Homes located in conservation areas or that are listed will almost always require planning permission before any significant modifications can be undertaken. 

Previous Loss of PD Rights 

If permitted development rights have been removed or previously used up by earlier works, then planning permission will be needed to proceed. 

In such scenarios, we assist clients in navigating planning requirements and securing consent where necessary, thanks to our in-house planning and design expertise.  

Permitted Development Rules at a Glance 

Condition  Allowed under Permitted Development 
Additional roof volume (terrace)  Up to 40 m³  
Additional roof volume (semi/detached)  Up to 50 m³  
Material matching  Required  
Side windows  Obscure glazed, 1.7 m+ above floor  
Roof modifications altering appearance  Not allowed without planning 

 

Our Approach to Permitted Development Loft Conversion Projects 

At Bigger Living Lofts, our permitted development loft conversion services combine professional planning experience and skilled craftsmanship. With over 30 years’ experience in the loft conversion industry, we take the stress out of complex building projects.  

End-to-End Service 

From initial survey and design guidance, through planning advice, right up to the final build, we offer comprehensive support. Our team of engineers, designers and project managers ensure every stage meets quality standards and runs smoothly.  

We also offer a 10-year workmanship guarantee and can provide insurance-backed guarantees upon request.  

Proven Client Satisfaction 

Our reviews speak for themselves. Clients praise our professionalism, attention to detail and communication throughout the loft conversion journey.  

Give us a call on 01732 523199 or email info@biggerlivinglofts.com. 

 

FAQ – Permitted Development Loft Conversion  

What does permitted development loft conversion mean?

It means converting your loft into living space without a planning application if your project fits within specific volume limits and conditions.  

Do I still need building regulations approval?

Yes. Even with permitted development rights, building regulations approval is required to ensure safety, insulation and structural compliance.  

Can I build a dormer under permitted development?

Yes, as long as it stays within volume, height and material criteria.  

What happens if my project exceeds limits?

You will need to apply for full planning permission through your local authority.