Do I Need Building Control for a Conservatory

In many cases, you do not need Building Control approval to build a conservatory in the UK, provided it meets specific criteria. While planning permission often receives the most attention during home improvement projects, Building Regulations are equally important. They set the technical standards for safety, insulation, structure and more. Whether or not your conservatory requires Building Control depends on how it is designed, built and connected to the existing house.

When Building Control Is Not Required

Most standard conservatories built at ground level and attached to a domestic dwelling are exempt from Building Regulations if they are less than 30 square metres in floor area and separated from the main house by external-quality doors. To qualify for this exemption, the conservatory must be single-storey, have a translucent roof and glazed walls for at least 75% of the structure, and not interfere with the building’s drainage systems.

The space must remain thermally separate from the existing dwelling, meaning it cannot be fully open to the house or heated using the same central heating system. Independent electric heating, such as plug-in heaters or underfloor systems with separate controls, is allowed in exempt conservatories.

When Building Control Is Required

If the conservatory is over 30 square metres in size, open-plan to the house without exterior doors, or integrated with the home’s central heating system, then Building Control approval is usually required. This is because the space is then considered part of the habitable dwelling and must meet full Building Regulations relating to insulation, energy efficiency, fire safety, ventilation and structural integrity.

If the conservatory affects the existing building’s structure, such as by removing a supporting wall, Building Control approval is also required. Structural alterations need to be checked for stability, particularly around openings, lintels and load-bearing walls.

You will also need Building Control approval if the conservatory is built over a public sewer, alters drainage systems or connects to shared services that require inspection. In such cases, local authority Building Control teams will inspect foundations, thermal elements, electrics and other aspects of the build.

Conservatories in New Builds or Flats

If you live in a flat or maisonette, or if you are adding a conservatory to a newly built property still under NHBC or warranty cover, you are more likely to need Building Control involvement. Flats do not benefit from the same permitted development or exemption rights as houses. Structural integrity and fire safety between dwellings are also more complex in these cases.

In new builds, warranty providers often require conservatories to be signed off by Building Control to avoid invalidating cover. It is important to check the terms of your new home warranty before building.

Other Considerations

Even if Building Control is not required, the conservatory must still comply with other legal requirements. Planning permission may be necessary in conservation areas, listed buildings or for large conservatories that exceed permitted development limits.

Also, if you later remove the doors between the conservatory and house to create an open-plan layout, Building Control approval will be needed for that alteration—even if the conservatory itself was originally exempt.

Examples in Practice

A homeowner in York built a 20 square metre rear conservatory with a polycarbonate roof, double-glazed panels and patio doors connecting it to the house. It was built at ground level, with independent electric heating. The local authority confirmed that Building Control approval was not required as the conservatory met exemption criteria.

By contrast, a couple in Reading built a 35 square metre conservatory as part of an open-plan kitchen extension and connected it directly to their gas central heating. Because it exceeded the 30 square metre threshold and was open to the main dwelling, Building Control approval was required. Site inspections were carried out and a completion certificate was issued after the final inspection.

Conclusion

You do not need Building Control approval for a conservatory in most cases, provided it is under 30 square metres, at ground level, thermally separated and independently heated. However, if it becomes part of the habitable space, affects the structure or drainage, or connects to central heating, approval is required. Always check with your local Building Control team to confirm whether your proposed conservatory is exempt, especially if it is larger or part of a wider renovation project.