Do Conservatories Need Planning Permission?

Local Authority Permission Conservatory

Conservatories have been in use in England since the Victorian times. Once an outdoor getaway used for social outings, a conservatory blends the natural beauty of the outside with the comfort of the indoors. Mostly made of glass, a conservatory can serve as an excellent room for use throughout the year and is often a cost-effective alternative to full extension. But do you need permission for a conservatory?

In this article, we here at Ultraseal will outline when a conservatory requires planning permission, when they fall under permitted development, how to get building regulations approval and the application process.

Permitted Development Rights

Permitted Development Rights dictate what types of construction work can be done on a property without planning permission. To make things as simple as possible, we have broken down how the permitted development rules apply in the table below.

Restriction Category Specific Restriction Detached House Limit Semi-detached/Terraced House Limit
Size and Location Rear Wall Extension 4 metres 3 metres
Height Single-storey, not exceeding existing roof height Single-storey, not exceeding existing roof height
Land Coverage No more than half the area of land around the original house No more than half the area of land around the original house
Side Facing Road Not applicable Cannot be located on the side facing a road
Material and Design Ground Level Must be built at ground level Must be built at ground level
Maximum Height 4 metres 4 metres
Distance from Highway No closer than the original house No closer than the original house
Eaves Height (if within 2 metres of boundary) 3 metres 3 metres


Anything beyond the clear boundaries set within the table is a violation of your permitted development rights. If you are unsure about the information involved, speak to your local authority.

Are conservatories allowed via permitted development rights?

Typically, a conservatory is considered an extension of an existing house. They are single stories, and usually built within the size and location limitation set out in the permitted development rights table. For more clarification:

  • Single Storey Rear Extension – For a detached house, these can extend up to eight metres from the rear wall of the original house. For terraces or semi-detached homes, the maximum extension length is usually up to 6 metres from the rear wall.
  • Replacements of Existing Conservatories – If you’re replacing an existing conservatory, this will usually be ok so long as you’re not increasing its size.

When don’t you need planning permission for a Conservatory?

The following are criteria for which you won’t need planning permission.

Size Limits

There are size limits to adhere to so as not to violate planning permission rules. Some of these are a repeat of the previous section.

  • Detached Houses – Conservatories are allowed to extend up to 8 metres from the rear wall of the original house.
  • Terraces/Semi-Detached – The maximum extension length of a conservatory is usually up to 6 metres from the rear wall.
  • Garden Coverage – Any extensions can’t cover more than half the area of your original house.

Location Restrictions

Your conservatory placement is crucial, requiring you to adhere to location rules:

  • Principal elevation – Conservatories can’t extend beyond front walls, or any side wall facing the highway.
  • Height Limit
    • Maximum Eaves Height – The maximum eaves height refers to the lowest horizontal edge of the roof. Anything 3 meters or below will not require planning permission.
    • Maximum Overall Height – This refers to the highest point of your conservatory roof. It can go as high, but not higher than, the highest point of the roof of your house.
  • Single-Storey Extension – The permitted development rights only apply to conservatories that are single-storey. Multi-storey extensions almost always require planning permission.

Materials and Design

Permitted development rights allow for great flexibility as far as design goes, but there are some limits:

  • No Raised Platforms – Your conservatory should be built at the ground level, and it cannot be raised upon platforms, stilts or other elevating foundations.
  • Energy Efficient – Whatever design you go with, you must meet energy efficiency building regulations. The UK is moving in an energy-efficient, green-living direction, and the various updates to building regulations represent this. Examples of energy-efficient additions can be anything from insulation to installing the conservatory’s independent heating system.

Relevant Building Regulations

Building regulations apply to all building works, including extensions and outbuildings.

Regulations are extensive, but here is a quick rundown:

  • Structural Integrity – The conservatory must be structurally safe and sound. It must have adequate walls, foundations and a roof to withstand expected loads. The actual measurements depend on the size and location of the conservatory.
  • Insulation – Your conservatory must meet the minimum insulation standard for walls, floors and roofs specified within Section 1. Insulation is measured through U-value, which refers to how quickly heat escapes through a building element.
  • Fire Safety – Conservatories must have adequate fire safety measures. This means a means of escape and the use of fire-resistant materials within construction.
  • Ventilation – Ventilation is important for a healthy indoor environment and the elimination of nuisances such as condensation.

When do you need conservatory planning permission?

There are certain circumstances when you will require planning permission to build a conservatory, usually regarding how big or where the conservatory is to be built.

  1. Exceeding Size Limits – Your conservatory mustn’t exceed the size limit per the format outlined in the previous section. So, if it’s larger than the outlined dimensions, and if it covers half the garden area, planning permission may be necessary.
  2. Listed Buildings – If your home is listed, you will require a listed building consent. This is due to the architectural and historical interest assigned to the building. The government must consider all changes to listed buildings to ensure changes preserve their character.
  3. Conservation Areas – Properties that are within conservation areas are subject to strict planning control. The area’s unique character and appearance are essentially protected, and the local planning authority will want to ensure the area’s aesthetic remains intact.
  4. Designated Land – If your property is located within a designated land, such as national parks, areas of outstanding natural beauty (AONB) or world heritage sites, then special planning considerations may apply.
  5. Flats and Maisonettes – Permitted development rights typically don’t apply to flats or maisonettes, and most times, you’ll need planning permission.

Steps to take if you are unsure

It can be hard to judge where you stand regarding permitted development rules fully. The following are some steps to take if you’re unsure.

  1. Consult Local Planning Authority – The simplest way to iron out any rules you’re unsure of is to contact your local planning authority. They are experts on the specific rules, regulations, exceptions, etc., that apply in your area. Not all local planning authorities have the same rules. Even if you’re sure that your conservatory will fall into permitted development, you can stave off a lot of potential wasted time and headaches by consulting beforehand.
  2. Professional Advice – Many experts can give professional advice to staying within permitted development boundaries, such as architects, planning consultants etc. By assessing the attached house and possible extension to your living space, they can guide and possibly improve elements of the construction, and perhaps even help with the application process.
  3. Original House Clarification – One area that a lot of people trip up on without realising it is understanding where the original house begins and ends. Many houses may have already had extensions, causing a person to misjudge where the original boundaries lie. Before and after the construction process begins, the local building control officer will inspect the property.
  4. Consider the Impact on Neighbours – When planning your development, ensure that your conservatory doesn’t affect the back garden of your neighbouring property. For example, overshadowing their garden and blocking light.


Overall, there are many stages within the conservatory planning process that you’ll come up against the boundary between planning permission and permitted development. If you’re ever unsure, always consult your local authority for guidance.

FAQ: What happens if I build a conservatory without the necessary planning permission?

Building a conservatory and violating planning permission requirements without being aware is often viewed with understanding, as long as you’re willing to comply and make the recommended changes.

  1. Enforcement – If a violation is detected, the first thing that will happen is that you’ll likely be told to halt construction. Then, depending on factors determined by the local authority, you will have to either apply for retrospective planning permission or alter/demolish the existing conservatory to comply with permitted development. Bear in mind that retrospective planning application fees are higher than standard planning applications.
  2. Financial Implications – Aside from the extra expense of rectifying the construction, things can get quite expensive in situations of non-compliance. For example, if the local council finds that you’re not heeding their orders, they will likely pursue legal action. You will be required to have legal representation in this matter also.
  3. Property Value – If your situation with the planning permission is not rectified in due time, it may have adverse effects on your property’s value. You are required by law to notify the legal status of your extension to any potential buyers, and this would likely turn off many prospective buyers.
  4. Neighbour Disputes – If a dispute does arise between you and a neighbour as a result of the conservatory, and it’s reported and discovered that the conservatory was built without planning permission, the potential for more severe consequences goes up exponentially. 


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