Planning Permission vs Building Warrant: What’s the Difference?

Blog post description.

4/12/20252 min read

a room that has some tools in it
a room that has some tools in it
Planning Permission vs Building Warrant: What’s the Difference?

If you’re thinking about extending your home, converting your loft, or building a garden room, you’ve probably come across the terms planning permission and building warrant. These are two key approvals you may need before starting work, but they often get confused.

So, what’s the difference? Let’s break it down in simple terms.

What is Planning Permission?

Planning permission is all about how your project looks and how it fits in with the surrounding area. It’s granted by your local council’s planning department and focuses on things like:

  • The size and shape of your extension or building

  • How it affects your neighbours (like blocking sunlight or overlooking)

  • Whether it fits in with the character of the area

  • The impact on roads, access, and the environment

You’ll usually need planning permission for things like:

  • Larger extensions

  • New buildings (like garden rooms or garages)

  • Changes to the outside appearance of your home

  • Converting a garage into living space (sometimes)


However, smaller projects may fall under permitted development, meaning you don’t need to apply. We can help you check that before you start.

What is a Building Warrant?

A building warrant, on the other hand, is all about the technical side of things; making sure your project is safe, energy efficient and meets all building regulations. It’s granted by your local authority’s building standards department and covers things like:

  • Structural safety

  • Fire safety

  • Insulation and energy use

  • Drainage, ventilation

  • Accessibility


You’ll need a building warrant for almost all building work, even if planning permission isn’t required. That includes:

  • Internal alterations (like removing a wall or moving a bathroom)

  • Loft conversions

  • Extensions

  • Garage conversions

  • Installing structural beams


In Simple Terms…

  • Planning permission = Is the project allowed to happen here?

  • Building warrant = Is the project designed and built safely?



Do I Need Both?

Sometimes yes, sometimes no.

  • You might need both for something like a new extension or garden room.

  • You might need just a building warrant for internal alterations or a loft conversion that doesn’t change the outside look.

  • You might not need either, if your project falls under permitted development and doesn’t require structural work.


At AXSYS, we take care of all of this for you. We’ll advise what approvals you need, prepare the drawings, and handle the applications—making sure your project stays compliant, efficient, and stress-free.

Got a Project in Mind?

Get in touch with AXSYS today. We’re here to help you navigate the process and bring your ideas to life without the jargon.

contact@axsysdesign.co.uk