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Do you need planning permission for a loft conversion?

A guide to what planning permission for loft conversion options are open to you, and how to get the most out of this potential.

4 min read

One of the first questions you may have when considering a loft conversion for your home is whether you need planning permission. The answer is not always straightforward and depends on a number of key factors.

To help you embark on your home improvement journey, our planning team have prepared this helpful guide.

Do you need planning permission for a loft conversion?

Short answer: maybe.

Loft conversions come in all sorts of shapes and sizes, and whether or not you need planning permission will depend on these factors:

  • The type of loft conversion
  • The size
  • What type of house you live in
  • Where you live in the UK

Some loft conversion projects may fall under permitted development rights, allowing you to carry out your project without the need for Planning Permission. Read on to find out more about whether or not your project qualifies.

Permitted Development Rights for Loft Conversions

A Government scheme designed to get more homeowners expanding their properties, permitted development rights let some loft conversions go ahead without the need for planning permission.

In order to quality, your conversion must fit within these guidelines:

  • A volume allowance of 50 cubic metres additional roof space for detached and semi-detached houses
  • Uses similar building materials to the existing house
  • The development must not include a window in any wall or roof slope forming a side elevation of the dwelling house
  • The roof pitch of the principal part of the dwelling must be the same as the roof pitch of the existing house
  • A dormer wall that is set back at least 20cm from the existing wall face
  • Has windows that are non-opening if less than 1.7m from the floor level
  • Has side windows that are obscured/frosted

It’s worth noting, these allowances include anything added to the original house ("original" being the latest of when the property was built or if it was built before 1948, then as it stood on 1st July 1948). So if your loft has already been extended by a previous occupant that counts towards your cubic metres.

Naturally, these rules can be quite confusing, especially if this is your first conversion. To make sure things run smoothly, we recommend getting an architect by your side, to make sure your permitted development rights are used… well, right.

Permitted Development and Planning Permission for Loft Conversions

Lawful Development Certificate

If you do opt to use your permitted development rights, we highly recommend obtaining a lawful development certificate.

It essentially proves to both your local authority and future buyers that your home project was legal at the point of construction. This protects you in the event the rules around permitted development right change, and ensures all the guidelines have been met.

If your project is found to be in violation of the rules, you can face both some hefty fines, and even the prospect of demolishing your conversion. Risks no homeowner should be taking!

Homes that need planning permission for a loft conversion

While permitted development rights are great, they don’t apply to all house types.

  • Flats
  • Maisonettes
  • Listed buildings
  • Homes in conservation areas

These homes are all excluded from the scheme, and will require planning permission.

Loft main dormer© Veronica Rodriguez

Types of loft conversions and whether they need planning permission or not

When it comes to expanding your loft space, there are four traditional options homeowners often go for - each with its own planning considerations.

Roof light loft conversion

A roof light or room in loft conversion is where you don’t alter or expand the existing space at all, but simply add in windows and reinforce the floor to transform an attic into a comfortable living space.

Roof light loft conversions rarely need planning permission.

Dormer loft conversion

The most popular type of loft conversion is a simple flat roof dormer. This is a structural extension which projects vertically from the slope of the existing roof, creating a box shape. This loft extension generally requires no dramatic changes, and allows for the installation of conventional windows.

Planning permission is often not required for dormer loft conversions.

Hip to gable loft conversion

Ideal for end of terrace and detached homes, a hip to gable loft conversion straightens an inwardly slanted end roof to create a vertical wall. This small change can make a huge difference to the feel of the living space inside, and is becoming an increasingly popular option for homeowners.

Planning permission might be needed for a hip to gable loft conversion.

Mansard loft conversion

Constructed by raising the party wall (the wall shared with your neighbours). The roof remains flat, while one outer wall slopes gently inwards. Mansards are typically found at the rear of the house, and although they are suitable for many property types, they are most popular in terraced houses.

Mansard loft conversions often require planning permission.

Planning permission for loft conversion

How Resi can help you with your loft conversion journey

Are you ready to begin your home transformation journey? Then this is the place to start.

Through our online Dashboard, we’ll guide you through each step of the process, as your designer packages up your ideas into a set of architectural drawings. We’ll then pass you over to our planning team, who will act as your agent, and give you the best chance of first time approval.

At Resi, we’ve helped over 1000 homeowners secure planning approval. Whether through a full planning application, or by using your permitted development rights, we’ve got all the expertise you’ll need!

Discover your home’s potential by book in a free consultation with our team.

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Is planning permission required for a loft conversion?

Planning permission for a loft conversion is not always required. This depends on the type of loft conversion, its size, the type of house you live in, and your location in the UK.

What homes require planning permission for a loft conversion?

Flats, maisonettes, homes in conversation areas and listed buildings.

What different types of loft conversions are there?

Traditional options homeowners often chose are roof light loft conversion, dormer loft conversion, hip to gable loft conversion and mansard loft conversion.

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