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.
Do I Need Planning Permission for a Conservatory in Brentwood?
A glazed extension, typically to the rear of the property, used as a living or dining space. Conservatories follow the same permitted development rules as single-storey extensions but may be exempt from Building Regulations if they meet certain conditions.
Planning in Brentwood
83%
of planning applications granted
90%
decided within the statutory or agreed time
36%
of householder applications decided within 8 weeks
In the year to December 2025, Brentwood decided 742 planning applications. 455 of these were householder projects such as extensions, loft conversions and outbuildings, of which 85% 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 Brentwood
Brentwood has 13 conservation areas. These include Blackmore, Brentwood Town Centre, Fryerning, Great Warley, Herongate, Highwood Hospital, Brentwood. 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 Brentwood planning department before starting work to confirm whether your property is affected by any special designations.
Permitted Development Rules for a Conservatory
Generally permitted under Part 1, Class A, following the same rules as single-storey rear extensions. Maximum depth of 3m (semi/terraced) or 4m (detached) under standard PD, extending to 6m or 8m under prior approval.
Conditions
- 1Same conditions as single-storey rear extensions
- 2Maximum depth 3m (semi/terraced) or 4m (detached) under standard PD
- 3Maximum height 4m; eaves 3m if within 2m of boundary
- 4Must not cover more than half the curtilage
- 5Must not be forward of the principal elevation
Size and Dimension Limits
- Maximum height: 4m
- Eaves height: 3m if within 2m of a boundary
- Depth: 3m (semi/terraced) or 4m (detached) under standard PD
When Permitted Development Does Not Apply
- Cumulative total of all extensions and outbuildings must not cover more than half the curtilage
- Restricted or removed in designated areas
- Removing the separating wall/door between conservatory and house triggers Building Regulations for thermal performance
What About Building Regulations?
Building regulations approval is not usually required
A conservatory is exempt from Building Regulations provided it is at ground level, under 30 square metres, has its own independent heating with separate controls, is separated from the house by external-quality walls, windows, and doors, and any glazing complies with safety glazing requirements. Removing the separating wall or door means Building Regulations apply in full.
Building regulations are separate from planning permission. Even if your project is permitted development, you may still need building regulations approval. Contact Brentwood building control or use an approved inspector.
How to Apply in Brentwood
If you need planning permission for your conservatory, you can apply through Brentwood's planning department or via the national Planning Portal.
If your project is permitted development and you want written confirmation, you can apply for a Lawful Development Certificate (LDC) from Brentwood. 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?
Enforcement risk is the same as for single-storey extensions. Conservatories that breach PD limits can face enforcement notices. Removing the separating wall without Building Regulations approval is a common issue flagged during property sales.
Frequently Asked Questions
Do I need planning permission for a conservatory in Brentwood?
Does a conservatory in Brentwood need building regulations?
How do I apply for planning permission in Brentwood?
How long does planning permission take in Brentwood?
What percentage of planning applications does Brentwood approve?
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