Lofts represent both potential and opportunity. They’re often overlooked and underused, but with a little design inspiration, they can be turned into unique, eye-catching and functional spaces. Whether you need an additional bathroom or bedroom, or perhaps a quiet place to work, there are endless ways in which a loft conversion can transform your home. 

Before we get carried away with design plans, it’s worth looking into the rules and regulations. In this post we’ll explain whether you need planning permission for a loft conversion, and how to go about obtaining it if you do.

Do I need planning permission for a loft conversion?

In most cases, planning permission isn’t required for loft conversions. This is because they tend to be considered a ‘Permitted Development’. This is a type of property extension which conforms to various criteria. These include:

  • The total additional space of an extension cannot exceed 40 cubic metres for a terraced property, or 50 cubic metres for a semi-detached or detached property (*note – previous additions to your property, even those made before your ownership, contribute to this limit).
  • The extension cannot extend the height or forward-most point of your current property.
  • Side-facing windows need to be obscured and stand at least 1.7m above the floor.
  • Except for hip to gable loft conversions, the conversion will need to be set back as far as practicable with a minimum of at least 20cm from the original eaves.
  • There are no raised platforms, verandas, or balconies.
  • The roof extension can’t overhang the outer face of the wall of the original property.
  • The property can’t be on designated land such as a national park, conservation area or a world heritage site.

Do I need planning permission for a dormer loft conversion?

As one of the most popular types of loft conversion, a dormer loft involves building an upright structure from a sloping roof. This results in more usable floorspace within a loft and gives occupants more headroom. When it comes to planning permission, dormer conversions are treated the same as other types of loft conversion; as long as it can be classed as a ‘Permitted Development’, you won’t need planning permission. 

How long does it take for planning permission for a loft conversion?

If you need to apply for planning permission for your loft conversion, the process can take up to 8 weeks to complete. Bear in mind, though, that it can be longer for more complex projects that require significant structural changes. 

Do I need buildings regulations approval for a loft conversion?

Yes. Building regulations approval is separate from planning permission, and is required regardless of whether your extension is a ‘Permitted Development’. This type of approval ensures that your intended extension is structurally viable, is compliant with fire safety rules, and has adequate sound insulation. Inspections are made before, during, and after construction by a building control service to make sure that every aspect is in line with regulations. 

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Loft conversions with Plus Rooms

We hope this short guide to planning permission for loft conversions proves helpful in your project. If there is anything you are still unsure about, feel free to get in touch. With extensive experience creating beautiful loft conversions in and around London, we’d be happy to help. And if you’d like some inspiration, take a look at some of our past loft conversion projects