Do I Need Building Control for Internal Works

Internal building work often seems straightforward — especially when it doesn’t involve extending a property or changing its external appearance. However, many internal alterations still fall under building regulations and require formal building control approval. It all depends on what you're changing, how it affects the structure, and whether it impacts the safety or performance of the building.

Building control is in place to make sure that any changes you make to the inside of a property are safe, legal, and in line with national standards. Ignoring this step can lead to fines, complications when selling, or being forced to redo the work.

Internal Work That Requires Building Control

Any structural changes inside a property are likely to require building control approval. This includes removing or altering load-bearing walls, chimney breasts, or structural beams. The reason is simple — these elements affect how the building supports itself, and altering them without proper oversight can compromise safety.

If you're creating new rooms, converting existing ones, or changing the layout in a way that affects fire escape routes or access, building control approval is usually required. For example, converting a garage into a habitable room, splitting a bedroom into two, or creating open-plan living spaces often triggers a need for inspection and sign-off.

Installing new staircases, creating loft rooms, or carrying out major rewiring or plumbing work can also require approval. These projects affect more than just aesthetics — they impact how the building functions in terms of ventilation, load capacity, insulation, and fire safety.

If you're adding bathrooms or kitchens where none previously existed, building control may be needed to inspect drainage, ventilation, and water supply. The same applies to installing or relocating boilers, fuse boxes, or heating systems.

Internal Work That Doesn’t Usually Need Approval

Not every change inside a property is subject to building control. Painting, decorating, replacing carpets or flooring, and installing new kitchen units or bathroom fixtures (where plumbing is unchanged) are generally considered cosmetic and don’t require approval.

If you're replacing doors, windows, or radiators in existing positions — and using approved products — these changes are usually exempt. However, if you're altering structural openings to fit new items or changing how the room is used, the rules may change.

The key distinction is whether the work affects the building’s structure, safety, energy performance, or use. When in doubt, it's best to ask building control for guidance before starting.

Competent Person Schemes and Internal Work

Some internal work — particularly electrical, heating, and plumbing — can be self-certified by a qualified installer under a Competent Person Scheme. This means the work doesn't need to be separately approved by the local authority, as the professional doing the job is registered to sign it off themselves.

This system speeds up the process and still ensures safety and compliance. You should always receive a certificate of compliance from the installer, which proves the work was carried out to building regulation standards.

Risks of Not Getting Approval

Carrying out internal work without building control approval when it is legally required can lead to serious consequences. The local authority may serve a notice requiring the work to be exposed or removed, or you may be forced to apply for retrospective approval, known as a regularisation certificate.

If you're selling or remortgaging the property, missing documentation can delay the process or reduce the value of your home. In worst-case scenarios, poor workmanship that went uninspected could create safety risks — and result in personal liability if something goes wrong.

Load-Bearing vs Non-Load-Bearing Walls

One of the most common internal changes is removing a wall to open up space. The key question is whether the wall is load-bearing. If it is, removing it without proper structural support is extremely dangerous and always requires building control approval.

Even if you're not sure whether a wall is structural, you must treat it as if it is until confirmed otherwise by a structural engineer or qualified builder. If steel beams (RSJs) are needed, structural calculations must be submitted, and the beam installation will be inspected by building control for safety and correct fire protection.

Non-load-bearing walls can sometimes be removed without approval, but you still need to consider how the change affects fire safety, acoustics, or access within the building.

Loft Rooms and Attic Conversions

Turning a loft into a usable room — even if it's not a full conversion — often requires building control approval. This is because the floor may need strengthening, insulation standards must be met, and a safe means of escape in the event of a fire must be included.

If you install a staircase or rooflights, or plan to use the space as a bedroom or office, you’ve changed the function of the loft and triggered the need for compliance with regulations covering structure, thermal efficiency, and fire escape routes.

Fire Safety and Internal Layout Changes

Internal layout changes might seem minor, but they can compromise fire escape routes, especially in multi-storey homes or flats. Removing doors, altering hallways, or opening up a kitchen to a stairwell can increase the spread of smoke and delay evacuation. Building regulations require that safe escape routes and fire separation are maintained — particularly between kitchens and sleeping areas.

Even swapping internal doors may require fire-rated replacements in certain buildings, especially if you're in a flat or converting the use of a room.

Sound Insulation and Flats

If you're carrying out internal works in a flat or maisonette, building control may pay closer attention to acoustic separation — especially between floors or adjoining units. This includes structural flooring upgrades or ceiling works that could reduce sound insulation performance.

If you’re installing new bathrooms, kitchens, or plumbing in flats, you also need to be careful about how waste and water supply interact with neighbouring properties, and ensure that changes don’t create noise or structural risk.

Replacing Stairs or Changing Floor Levels

Installing a new staircase, repositioning one, or significantly altering floor levels inside a property can trigger the need for building control approval. Stairs must meet rules on rise, going, headroom, and handrails. Even if it looks like a simple replacement job, any deviation from the existing layout should be checked for compliance.

This also applies to creating steps or sunken areas that change floor height — especially in basements or split-level homes.

Mechanical and Electrical Upgrades

Upgrading electrical systems, installing underfloor heating, or reconfiguring plumbing systems often requires oversight unless it’s being done under a Competent Person Scheme. Not all installers are registered, so if you're hiring a tradesperson who isn’t part of a scheme, the work must be inspected by building control.

This is particularly important for bathrooms and kitchens, where new lighting, sockets, or pipework are being added in wet zones.

Final Word

Not all internal work needs building control approval, but plenty does — particularly if you're changing the structure, layout, or essential systems of the building. It's always safer to check before starting. Internal alterations might seem hidden from the outside world, but the regulations still apply, and following the rules ensures your project is safe, legal, and future-proof.