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What happens if I build without planning permission?

If you carry out development without the necessary planning permission, and it doesn’t fall within permitted development rights, you may be in breach of the planning rules. In such cases, you will usually need to submit a retrospective planning application to seek approval for the work already completed or started. However, there is no guarantee that permission will be granted.  

Learn more about planning breaches on Planning Portal  

Common Questions

Do I need permission to demolish an old lean-to and rebuild to the same measurements?

Demolishing and building a new lean-to will still have comply with planning requirements.

If you live in a conservation area or listed building you may require approval for the demolition.

Whether a lean-to requires planning permission will depend on what the lean-to is used for, it may be an extension, pergola, carport, conservatory or gazebo.

In some cases a building a lean-to will be classified as permitted development, meaning an application for planning permission is not required provided specified limits and conditions are met. If these are exceeded, then you must apply for planning permission.

Permitted development rules vary based on the type of work you are completing, visit our interactive house mini guides for details on the specific rules.

If you live in a listed building, you will need listed building consent for any significant changes.

What permission is required to build a lean-to at the side of my house?

Whether a lean-to requires planning permission will depend on what the lean-to is used for, it may be an extension, pergola, carport, conservatory or gazebo.

In some cases a building a lean-to will be classified as permitted development, meaning an application for planning permission is not required provided specified limits and conditions are met. If these are exceeded, then you must apply for planning permission.

Permitted development rules vary based on the type of work you are completing, visit our Mini Guides for details on the specific rules.

If you live in a listed building, you will need listed building consent for any significant changes.

How high can I build a single-storey extension without planning permission?

A single storey rear extension can fall under permitted development, meaning planning permission may not be required providing it meets certain criteria.  

In terms of height, the extension must:

  • Be no taller than four metres at its highest point
  • Have eaves no higher than the eaves of the original house
  • Not exceed the height of the original dwelling  

Read about planning permission for extensions on Planning Portal

What are the planning and building rules for installing a toilet in the downstairs of a property?

Normally planning permission is not required for installing a toilet in an existing area of the property as the change is only internal. If the toilet is part of a wider project such as an extension permission may be required.

If you live in a listed building, then listed building consent will be required for any major changes.

Building regulations will apply to the installation of a toilet in a property, these will cover areas such as ventilation, plumbing and drainage, and size.

Is building regulations approval needed for a garage conversion?

The conversion of a garage, or part of a garage, into habitable space, will normally require approval under the building regulations.

As part of the garage conversion, it is likely that the original garage door will be in-filled with a new wall and possibly a window or door, and a new foundation may be needed for the new wall. 

As well as the foundation, you also need to consider:

  • Floor
  • Walls  
  • Ventilation

Read more about the building regulations for garage conversions.

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