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How Big Can a Conservatory be Without Planning Permission?

An image of a taken from a back garden of a conservatory constructed by Williams Windows DG Limited.

A conservatory can be a great addition to your home, but depending on its size and the way it is built, you may be required to obtain planning permission.

Planning permission and building regulations are often considered the same, however, in our latest post, we take a look at the differences between the two and how you can ensure you abide by both with your conservatory.

Planning Permission for Conservatories

Planning permission is meant to take into consideration the effect your new structure will have on the aesthetics of homes in the surrounding area. You will not need planning permission for some structures, depending on their size, position and various other factors. A conservatory may be built without obtaining planning permission first if the following apply:

The conservatory does not cover more than half the garden space you have.
The maximum height of the conservatory does not exceed more than four metres (or three metres if it is located within two metres of a boundary).
The top point of the conservatory does not exceed the eaves of a property’s roof.
If the conservatory is placed at the side of the house, it does not extend beyond half the width of the house.

Whilst most houses come with “permitted development rights” that mean some conservatories and single story extensions can automatically be built, it is worth noting that others do not and permission will need to be sought, regardless of the type of extension.

Building Regulations for Conservatories

Whilst planning permission is focused on the exterior appearance of extensions and how this may affect other residents or the local area, building regulations are there to set the standards for the construction industry and the health and safety of a building and its users.

When you build a conservatory, it must comply with building regulations, but will be exempt if the following apply:

It has its own independent heating system which is not connected to the central heating of the rest of the house.

It is no less than 1m away from any boundary.

80% or more of the roof is translucent.

The conservatory is less than 30sqm in size and built only at ground level.

If you plan to build an open plan conservatory where you will remove exterior walls or doors between your house and the conservatory, building regulations approval will be required. What’s more, you must prove that the new addition doesn’t result in the conservatory or rest of the house becoming less energy efficient.

Talk to us About Our Conservatories Today

If you have been considering investing in a conservatory, we welcome you to contact our dedicated team. We’ll discuss your plans with you and provide you with a quote. Please call today on 0208 428 5433. We look forward to hearing from you.


  • ‘The service provided was of a high standard by a professional team who clearly knew what they were doing. We couldn’t be happier with our brand new conservatory. Thank you to all involved…’

  • ‘My new front door has added light into the hallway and brightened up the exterior of my home. Everyone comments on it when they first see it. I would not hesitate to recommend Williams Windows to anyone…’

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