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 Stevenage?
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 Stevenage
94%
of planning applications granted
93%
decided within the statutory or agreed time
88%
of householder applications decided within 8 weeks
In the year to December 2025, Stevenage decided 266 planning applications. 138 of these were householder projects such as extensions, loft conversions and outbuildings, of which 93% 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 Stevenage
Stevenage has 7 conservation areas. These include Broadwater Conservation Area, Old Town High Street Conservation Area, Orchard Road Conservation Area, Shephall Green Conservation Area, St. Nicholas / Rectory Lane Conservation Area, Symonds Green Conservation Area. 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 Stevenage 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 Stevenage building control or use an approved inspector.
How to Apply in Stevenage
If you need planning permission for your conservatory, you can apply through Stevenage'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 Stevenage. 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 Stevenage?
Does a conservatory in Stevenage need building regulations?
How do I apply for planning permission in Stevenage?
How long does planning permission take in Stevenage?
What percentage of planning applications does Stevenage approve?
Find a Conservatory Specialist in Stevenage
Browse local conservatory specialists on Tradesfolk. Read reviews, compare quotes, and hire with confidence. 100% free for homeowners, always.