Does a Conservatory Need Planning Permission?

A conservatory is one of the most common home improvements in England. For planning purposes, it is treated identically to a single-storey rear extension — which means the same permitted development rules apply. Provided the conservatory stays within the prescribed limits, no planning application is needed.

However, planning permission is required in specific circumstances: if you exceed the size limits, if your home is in a conservation area and the conservatory affects the front or side of the house, or if your home is a listed building.

Conservatory Permitted Development Rules

Under Part 1 Class A of the Town and Country Planning (General Permitted Development) (England) Order 2015, a conservatory is permitted development as a single-storey rear extension if it meets all the following conditions:

Size Limits for a PD Conservatory

The key measurement is the rear projection — the distance from the original rear wall of the house to the back of the conservatory. “Original” means as built (or as it was on 1 July 1948 for older properties), before any extensions.

If you have already extended the house, the previous extension counts towards the limit. So if you added a 2m extension in 2010, you could only add a conservatory projecting 2m further (for a semi or terraced house) or 2m further (for a detached house).

Width is also relevant: the conservatory must not extend beyond the original side walls of the house (you cannot make it wider than the house itself).

When a Conservatory Needs Planning Permission

A conservatory needs planning permission if it:

• Exceeds the maximum rear projection (4m detached, 3m semi/terraced) — unless using the Neighbour Consultation Scheme
• Covers more than 50% of the original curtilage when combined with other extensions and outbuildings
• Exceeds 4m in height
• Would be situated on a side elevation or forward of the principal elevation
• Is on a flat above ground floor level (different rules apply)

If your property is in a National Park, Area of Outstanding Natural Beauty (AONB), or World Heritage Site, different restrictions may apply to the extent of permitted development.

Conservation Areas and Listed Buildings

Listed buildings require Listed Building Consent for any works that would affect the character of the building, in addition to (or instead of) planning permission. Even a conservatory on a listed building that would otherwise be PD may need Listed Building Consent. Always check with the local planning authority before starting work on a listed building.

Building Regulations for Conservatories

A conservatory may be exempt from building regulations if it meets specific criteria:

• Ground floor only
• Floor area less than 30m²
• Separated from the house by walls, doors or windows of the same standard as external walls/windows
• The heating system is not extended into the conservatory

If any of these conditions are not met, building regulations approval is required. The 2022 Part L changes introduced new minimum insulation requirements for conservatories that do not meet the exemption criteria. A non-exempt conservatory must meet current standards for walls, roof and glazing.

Frequently Asked Questions