Building regulations vs planning permission

Planning permission and building regulations are two separate approval systems.

What planning permission controls

Planning permission regulates the use of land and buildings.¹ It asks: Is this development acceptable in this location? Will it harm the character of the area? Will it affect neighbours? Does it comply with local and national planning policy?

Planning permission covers:

• External appearance and design (size, height, materials, visual impact)
• Siting and layout (where the building sits on the plot)
• Impact on neighbours (overlooking, loss of light, overbearing effect)
• Change of use (e.g., house to shop, office to residential)
• Highway safety and parking provision
• Impact on heritage assets, conservation areas, green belt
• Landscape and ecology

Planning permission is about the principle and external impacts of development. It does not regulate structural safety, insulation, or how the building is constructed internally. That is the role of building regulations.

See our guide on what is planning permission for more detail.

What building regulations control

Building regulations set minimum technical standards for construction.² They ensure buildings are safe, energy-efficient, accessible, and durable.

Building regulations cover:

• Structural stability (foundations, walls, roofs)
• Fire safety (escape routes, fire doors, compartmentation)
• Sound insulation (between dwellings and rooms)
• Ventilation and air quality
• Energy efficiency and thermal insulation
• Drainage and waste disposal
• Electrical safety
• Access and facilities for disabled people
• Glazing safety (e.g., toughened glass in critical locations)
• Stair design and guarding (handrails, balustrades)

Building regulations do not care what the building looks like or whether it fits the streetscape. They care whether it is built correctly and safely.

Why you need both

Planning permission and building regulations serve different purposes. One does not replace the other.

Example: rear extension

Planning permission confirms the extension is acceptable in size, design, and impact on neighbours. It checks the external materials, proximity to boundaries, and whether it harms the character of the area.

Building regulations check the foundations are adequate, the walls are structurally sound, the roof is insulated to current standards, and there is adequate ventilation and drainage.

You can have planning permission and still fail building regulations if the construction is substandard. Equally, work that complies with building regulations may be unauthorised if you did not get planning permission.

When you need planning permission but not building regulations

Some works require planning permission but are exempt from building regulations:

• Change of use with no building work (e.g., shop to café, if no structural alterations)
• Boundary walls and fences (planning may be needed if over 2 metres, but building regs do not apply)
• Small detached outbuildings under 15m² with no sleeping accommodation (exempt from most building regs)

Always check. Even if work is exempt from building regulations, certain elements (electrical work, drainage connections) may still need to comply.

When you need building regulations but not planning permission

Some works are permitted development (no planning permission needed) but still require building regulations approval:

• Internal alterations (removing walls, creating new bathrooms or kitchens)
• Loft conversions (permitted development in many cases, but always need building regs)
• Replacement windows and doors (permitted development, but must meet thermal and safety standards under Part L and Part N of building regs)
• Re-roofing (planning permission rarely needed, but building regs apply if you change the structure or insulation)
• Boiler replacement or new heating system (building regs apply, planning permission not needed)

This is a common source of confusion. Homeowners assume that if planning permission is not needed, they can proceed without any approvals. Not true. Building regulations almost always apply.

How to apply for building regulations approval

Building regulations approval is separate from planning permission.³ You submit a building control application to either:

• Your local authority building control team, or
• An approved inspector (a private building control body)

Both routes are equally valid. Approved inspectors are often faster and may cost less, but local authority building control can enforce breaches retrospectively, which approved inspectors cannot.

Application routes:

• Full plans application: Submit detailed drawings showing how the work will comply. Building control reviews and approves before work starts. This gives certainty.
• Building notice: Notify building control that work will start. No upfront approval. Building control inspects as work progresses. Faster but riskier (you may have to alter work if it does not comply).

Most people use full plans for extensions and loft conversions. Building notice is common for smaller works like garage conversions or re-roofing.

Fees vary by council and project size. Expect £400 to £1,500 for a typical extension. Approved inspectors may charge less but quote per job.

Inspections and completion certificates

Building control inspects work at key stages:⁴

• Foundation excavation (before concrete is poured)
• Oversite (ground floor slab or insulation)
• Drainage (before backfilling trenches)
• Completion (final inspection when work is finished)

You must notify building control at each stage. If you concrete over foundations before the inspection, building control can require you to dig them back up. This is expensive and delays the project.

When work is complete and passes final inspection, building control issues a completion certificate. This confirms the work complies with building regulations. You need this certificate to sell the property. Lenders and solicitors will ask for it. Without it, the work is non-compliant and may reduce the property value.

What happens if you skip building regulations

Building without approval is a breach of building regulations.⁵ The local authority can serve an enforcement notice requiring you to expose the work for inspection, provide calculations, or undo non-compliant work.

If the work is very old (over 12 months and the building has been occupied), the council may issue a regularisation certificate instead. This retrospectively approves the work if it can be shown to comply. It costs more than a standard application and requires invasive inspections or calculations.

Selling a property with uncertified building work is difficult. Solicitors will raise it in searches. Buyers will reduce their offer or require an indemnity policy. Better to get it sorted before listing.