When is Building Control Required

Building control is a legal requirement for many types of construction, renovation, and installation work in the UK. It exists to ensure that work on homes and buildings is carried out safely, to a minimum standard, and in accordance with national regulations. But not every project needs approval — so how do you know when it’s required?

The answer lies in the type of work being done. If it affects the structure, energy performance, safety, or essential services of a property, it’s likely to need building control approval. Whether you're making major changes or small internal adjustments, understanding when these rules apply is critical to avoiding delays, penalties, or dangerous outcomes.

New Builds and Structural Work

Building control is always required for new builds, whether it's a single dwelling, a block of flats, or commercial premises. From foundations to roofing, the entire project must be inspected and approved at key stages.

The same applies to structural alterations on existing buildings. This includes removing or altering load-bearing walls, changing structural beams, building extensions, and converting roof spaces. These changes directly affect the safety and integrity of the building, which is why they fall under strict regulation.

Chimney removals, underpinning, and large openings created for doors or windows are also classed as structural work and must be approved by building control.

Conversions and Change of Use

If you're converting a space into a different type of room or changing how a building is used, building control is likely to be involved. Converting a loft into a bedroom, turning a garage into a living area, or splitting one home into two separate dwellings all require approval.

Even if the space already exists, the change of use brings new requirements for ventilation, insulation, fire escape, soundproofing, and structural strength. The regulations are there to ensure the converted space is as safe and efficient as the rest of the building.

Extensions and Conservatories

Most extensions need building control approval, including single-storey, double-storey, and wraparound designs. The work must comply with regulations covering insulation, damp-proofing, foundations, structural stability, and drainage.

Conservatories are sometimes exempt, but only if they meet specific conditions. If the conservatory is larger than 30 square metres, not separated from the house by external doors, or includes fixed heating from the main system, it will likely require approval. Replacing a conservatory roof with a solid or tiled version also usually falls under building control rules.

Internal Works and Installations

Internal work can also trigger building control requirements. Removing internal walls, installing new staircases, or altering floor layouts often needs approval — especially if it affects fire escape routes or the structural layout.

Electrical and plumbing work may also fall under the regulations, particularly when it involves rewiring, new circuits, or work in kitchens, bathrooms, and other ‘special locations’. Heating system upgrades, boiler replacements, and new drainage connections are also covered.

Using a professional who’s part of a Competent Person Scheme can simplify this process, as they can self-certify certain types of internal work.

Energy and Safety Upgrades

Projects that improve energy efficiency can sometimes require approval. This includes installing cavity wall insulation, replacing windows and doors, or re-roofing a property. These changes must meet minimum performance standards and often need to be assessed.

Fire protection systems, sprinkler installations, and alarm systems in certain buildings also fall under building regulations, especially in flats, HMOs, and commercial properties.

The Difference Between Building Control and Planning Permission

Many homeowners confuse planning permission with building control, but they serve different purposes. Planning permission governs how a building looks, where it's placed, and how it impacts the surrounding area. Building control, on the other hand, focuses on how the building is constructed and whether it’s safe, energy-efficient, and legally compliant.

You may need one, both, or neither — but never assume that getting planning permission automatically means you don’t need building control approval. They’re entirely separate systems.

Emergency and Urgent Work

In some cases, emergency work — like fixing a dangerous structural fault, repairing collapsed drainage, or making urgent electrical repairs — may have to begin before formal approval is granted. While safety always comes first, you are still legally required to notify building control as soon as possible afterward. They may inspect the work retrospectively or ask for evidence, including photos, receipts, or structural calculations.

Even urgent work isn’t exempt from building regulations. You’ll still need to prove that it was done to an acceptable standard.

Listed Buildings and Conservation Areas

If your property is listed or located in a conservation area, building control rules still apply — but in many cases, they become stricter. You may also need listed building consent, which is entirely separate from both planning and building control.

Structural alterations, window replacements, and energy efficiency upgrades often trigger additional scrutiny. Insulation, glazing, and materials must usually match the original character of the property. In some cases, you may need specialist reports or conservation officer sign-off before building control can approve the work.

Projects That Might Seem Minor — But Still Need Approval

There are several types of work that homeowners often assume are too small to need building control — but they actually do:

• Converting part of an integrated garage into a utility or bathroom

• Installing or replacing a flue, chimney, or extractor fan

• Replacing a roof with new materials that change insulation or structure

• Creating a new opening for a window or door, even in the same wall

• Installing underfloor heating

If any of these changes affect fire safety, insulation, drainage, structure, or energy performance, they fall under building control regulations.

Building Control and Sale of Property

Even if no one notices the lack of approval at the time of building, it can come back to bite you when you try to sell. Solicitors acting for buyers will request evidence that structural work, extensions, and installations were completed in line with building regulations. If you don’t have the completion certificates, it can stall the sale, reduce the value of your home, or force you to apply for retrospective regularisation.

In some cases, sellers resort to indemnity insurance, but this only covers legal liability — not actual safety. It’s far better to follow the correct process and get everything approved from the outset.

DIY Projects and Building Control

If you’re taking on work yourself, rather than using a contractor, you’re still responsible for meeting the same standards. DIY doesn’t exempt you from building control. In fact, building inspectors may look more closely at owner-led projects to ensure the work is structurally sound and fully compliant.

Trying to save money by skipping approval can often lead to more expensive consequences later — including having to undo or rebuild non-compliant work.

Final Word

Building control is required in more situations than many people realise. If your work affects structure, layout, services, or safety, you almost certainly need approval. These rules aren’t just red tape — they protect lives, property, and future investment. Always check with your local building control team or an approved inspector before starting work. It’s a simple step that avoids costly mistakes and ensures your project is safe, legal, and properly documented.