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This is general guidance based on standard permitted development rights in England. Rules differ for listed buildings, conservation areas, and properties with Article 4 directions. Always confirm with your local planning authority before starting work.

Depends on Your Specific SituationCherwell (South East)

Do I Need Planning Permission for New Window Openings in Cherwell?

Creating new window openings in existing walls where none previously existed. This is generally permitted but side-facing windows at upper-floor level have specific restrictions to protect neighbours' privacy.

Planning in Cherwell

93%

of planning applications granted

79%

decided within the statutory or agreed time

49%

of householder applications decided within 8 weeks

In the year to December 2025, Cherwell decided 1,082 planning applications. 545 of these were householder projects such as extensions, loft conversions and outbuildings, of which 95% were granted.

Planning statistics: MHCLG planning application statistics, the year to December 2025. Conservation area and Article 4 data: planning.data.gov.uk, © Historic England / Crown copyright. Open Government Licence v3.0.

Important: Additional Restrictions May Apply in Cherwell

Cherwell has 60 conservation areas. These include Adderbury, Ardley, Balscote, Banbury, Barford St John, Barford St Michael. If your property is in a conservation area, some or all permitted development rights may be restricted. For example, you may need planning permission for changes that would normally be permitted, including alterations to the roof, cladding, or extensions visible from a public highway.

Check with Cherwell planning department before starting work to confirm whether your property is affected by any special designations.

Permitted Development Rules for New Window Openings

Adding new windows to existing walls is generally permitted under Part 1, Class A, provided the windows do not overlook neighbouring properties. Side-facing upper-floor windows must be obscure glazed and non-opening below 1.7m from the floor. New windows in the front elevation may change the building's appearance and could need PP in some areas.

Conditions

  • 1Side-facing windows at upper-floor level must be obscure glazed and non-opening below 1.7m from the floor
  • 2New windows should not significantly alter the external appearance of the dwelling
  • 3Must comply with Building Regulations (structural, thermal, safety glazing)
  • 4Check if the property has any Article 4 directions restricting window changes

Size and Dimension Limits

  • No specific PD size limits for individual windows
  • Structural lintel and support requirements apply based on wall type and opening size

When Permitted Development Does Not Apply

  • Listed buildings require listed building consent
  • Conservation areas may restrict new openings on visible elevations
  • Overlooking is the most common reason for neighbours to object
  • Creating large new openings in structural walls requires Building Regulations approval

What About Building Regulations?

Building regulations approval is likely required

Building Regulations approval is required covering structural support (lintels, padstones), thermal performance of the new window (Part L), safety glazing in critical locations (Part K), security requirements (Part Q, PAS 24), and ventilation (Part F). A structural engineer may be needed for large openings in load-bearing walls.

Building regulations are separate from planning permission. Even if your project is permitted development, you may still need building regulations approval. Contact Cherwell building control or use an approved inspector.

How to Apply in Cherwell

If you need planning permission for your new window openings, you can apply through Cherwell's planning department or via the national Planning Portal.

Timeline:8 weeks for householder planning applications if PP is needed.
Cost:£258
Visit Cherwell Planning

If your project is permitted development and you want written confirmation, you can apply for a Lawful Development Certificate (LDC) from Cherwell. This provides proof that your project does not need planning permission, which can be helpful when selling your property.

What Happens If I Build Without Permission?

Moderate risk if the new window overlooks a neighbouring property without being obscure glazed where required. The council can require the window to be altered or blocked up. This is a common source of neighbour disputes and enforcement complaints.

Frequently Asked Questions

Do I need planning permission for new window openings in Cherwell?
Adding new windows to existing walls is generally permitted under Part 1, Class A, provided the windows do not overlook neighbouring properties. Side-facing upper-floor windows must be obscure glazed and non-opening below 1.7m from the floor. New windows in the front elevation may change the building's appearance and could need PP in some areas. Note: Cherwell has 60 conservation areas (including Adderbury, Ardley, Balscote) where permitted development rights may be restricted. Check with Cherwell planning department.
Does new window openings in Cherwell need building regulations?
Yes. Building Regulations approval is required covering structural support (lintels, padstones), thermal performance of the new window (Part L), safety glazing in critical locations (Part K), security requirements (Part Q, PAS 24), and ventilation (Part F). A structural engineer may be needed for large openings in load-bearing walls. Contact Cherwell building control or an approved inspector for details.
How do I apply for planning permission in Cherwell?
You can apply for planning permission through Cherwell's planning department or via the national Planning Portal. £258. 8 weeks for householder planning applications if PP is needed..
How long does planning permission take in Cherwell?
Most planning applications should be decided within 8 weeks (13 weeks for major projects). In the year to December 2025, Cherwell decided 79% of applications within the statutory or agreed time, and 49% of householder applications within 8 weeks.
What percentage of planning applications does Cherwell approve?
Cherwell granted 93% of the 1,082 planning applications it decided in the year to December 2025. For householder applications such as extensions and outbuildings, the approval rate was 95%.

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