Planning Permission vs Building Regulations

Two completely different things

One of the most common sources of confusion for homeowners is the difference between planning permission and building regulations. They sound similar, they're both administered by your local council, and you need to understand both before starting any extension or alteration.

In short:

• Planning permission is about whether you're allowed to build it — its size, appearance and impact on neighbours.
• Building regulations are about whether it's built correctly — structurally sound, energy efficient, safe.

You can have planning permission and still fail building regulations. You can also be exempt from planning permission but still need to comply fully with building regulations.

Planning permission

Planning permission governs the principle of development. It considers the design, scale, materials and the effect your project will have on the street and your neighbours.

Many extensions fall under Permitted Development — meaning you don't need to submit a full planning application, provided you stay within specific size and height limits. However, the rules are detailed and there are exceptions (conservation areas, listed buildings, flats, etc.).

If your project exceeds permitted development limits, you'll need to submit a full planning application, which typically takes 8 weeks for a decision.

Building regulations

Building regulations are entirely separate. They ensure the construction meets national standards for:

• Structural integrity — foundations, steelwork, walls
• Fire safety — escape routes, smoke alarms
• Energy efficiency — insulation, glazing, heating
• Drainage and ventilation — waste, air flow, moisture control
• Accessibility — where applicable

Even a small extension that doesn't need planning permission will need building regulations approval. This involves submitting plans, having inspections at key stages (foundations, damp-proof, structure, drainage, completion), and receiving a completion certificate.

Which do you need?

For most extensions and structural alterations, you'll need both — either full planning permission or a lawful development certificate (to prove permitted development), plus building regulations approval.

This is one of the many things we handle and explain during the consultation. We'll tell you exactly which approvals your project needs and guide you through the process from start to finish.

Get in touch using the form on our contact page to discuss your project.