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Do I need planning permission for my flat or maisonette?

2 min read
• Oct '25 • by Heather

Quick summary

You generally need planning permission for changes to flats or maisonettes, especially for building extensions, converting lofts that alter roof space, or creating new flats, which can take several weeks and cost hundreds to thousands of pounds depending on the project size. Leasehold owners may also need freeholder consent, and listed buildings require extra permissions like listed building consent.

Flats and maisonettes do not fall within your permitted development rights, meaning you will have to seek planning permission for changes you want to make to your property.

Not only this, most flats are owned through a leasehold. This means, depending on your project, you may also have to seek the freeholder’s consent.

However, all of this doesn’t mean it’s impossible to carry out work on your flat. Just that you’ll have a few hoops to jump through.

Here’s some changes you might be considering…

Building an extension on a ground-floor flat

When adding an extension onto a ground floor flat, planning permission is a must.

Don’t worry, with the right architect by your side, this doesn’t have to be a stressful process. They’ll research your area so they can work out what design will give you the best chance of approval. At Resi, we’ll even submit the paperwork for you.

If extending a listed building, you’ll need to obtain ‘listed building consent’ from your local planning authority, as well as consulting them beforehand on your plans.

Remember: failure to obtain permission before construction on a listed building is a criminal offence.

How much does an architect charge?

Converting loft space in a top floor flat

You might avoid needing planning permission, if your conversion only affects the interior of the building. However, this changes if you’re planning to extend or alter the building’s roof space, such as inserting roof-lights, its is likely that you will require planning permission.

In all scenarios, it’s best to contact your local authority for advice on your conversion as some councils are stricter than others, when it comes loft conversions.

As with extensions, if your building is listed, you’ll have to obtain listed building consent before any work begins. Otherwise, you could be breaking the law.

You’ll also need to make sure you own the space you’re converting. As a leaseholder, you might not be entitled to the space, and will have to go through your freeholder, landlord, or management company. At Resi we can provide you with some useful tips on how to negotiate the purchase of this space, without having to pay for it.

Find Out: What’s the difference between freehold and leasehold?

What else will I require planning permission for on my flat?

  • If you want to convert your space into multiple homes, as either more flats or bedsits.
  • You might need planning permission to change the windows of your property - such as fitting new double-glazing. However, if this won’t be the case if the work only takes place internally.
  • It’s not unheard of that flat owners need planning permission to install a satellite dish onto their property, especially in Conservation Areas.

If unsure about your right to expand or renovate your flat or maisonette, simply contact our team for a free consultation call.

How much does an architect charge?

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