Planning Permission vs Building Regulations: The Difference

Planning permission and building regulations are two separate approvals. Planning decides whether you can build and how it looks; building regulations make sure it's built safely. Most UK extensions need building regulations sign-off even when planning permission isn't required, so the two go hand in hand.

Two phrases strike fear into the heart of every would-be extender: "planning permission" and "building regulations." They sound similar, they often get muddled, and together they cause more sleepless nights than anything else in a project.

Let's clear up the confusion once and for all.

They're Two Different Things

This trips up almost everyone, so let's be crystal clear:

• Planning permission is about whether you can build it — the size, appearance, and impact on the area.
• Building regulations are about how you build it — the structural safety, insulation, fire safety, and technical standards.

You can need one, the other, both, or (occasionally) neither. They're separate approvals from separate departments, and passing one doesn't mean you've passed the other.

Planning Permission in a Nutshell

As we've covered, many extensions fall under permitted development. But if yours needs full planning permission, the council will assess things like size, design, impact on neighbours, and how it fits the area.

The process typically takes around 8 weeks for a decision, though complex cases take longer.

Building Regulations: The Non-Negotiable Bit

Here's the part people underestimate. Even if you don't need planning permission, you'll almost certainly need building regulations approval. This covers:

• Structural integrity — Will it stand up safely?
• Insulation and energy efficiency — Meeting modern thermal standards
• Fire safety — Escape routes, alarms, fire-resistant materials
• Ventilation and damp proofing — Keeping the space healthy
• Drainage — Properly handling waste and rainwater

These aren't optional extras. They're the difference between a safe, valuable home and a liability.

The Paper Trail That Protects You

When the work's done, you'll receive a completion certificate. Guard it with your life. When you come to sell, buyers' solicitors will want to see it. No certificate can mean a stalled sale or a reduced price.

How the Two Fit Together

A typical extension journey runs like this:

1. Check if you need planning permission (or if it's permitted development)
2. Submit planning application if required
3. Develop detailed building regulations drawings
4. Get building control sign-off as work progresses
5. Receive your completion certificate

Miss a step, and you store up problems for later.

Why a Good Architectural Designer Makes the Difference

Juggling both systems is exactly where good design pays off. We handle the drawings, the applications, and the technical detail — so you don't have to decode council jargon or worry about missing a requirement.

Let's Take the Stress Off Your Plate

Feeling overwhelmed? That's normal — and it's exactly what we're here for. Let us handle the planning and building regs maze for you, start to finish.