General Planning Rules for All Extensions

If you're considering an extension, it can often fall under 'permitted development'. This means you might not need to go through the full planning application process, but only if your project strictly adheres to these fundamental requirements:

• Site Coverage: Your new extension, along with any other existing outbuildings, must not cover more than half (50%) of the land area surrounding the 'original house' (this refers to the footprint of the house as it was on 1st July 1948, or when it was built if later).

• Overall Height: The highest point of your extension's roof must not be taller than the highest part of your home's current roof. Additionally, the height of its eaves (the lower edges of the roof where it overhangs the walls) cannot exceed the eaves height of your existing property.

• Boundary Proximity: Should any part of your extension be built within two metres of your property's boundary, its eaves must be no higher than three metres from ground level.

• Building Line: You are prevented from constructing an extension forward of the 'principal elevation' – typically the front wall of your house that faces a public road. Furthermore, if a 'side elevation' (a side wall) is adjacent to a public highway, you cannot build an extension forward of that particular wall either.

• Excluded Elements: Your proposed extension cannot incorporate certain specific features. These include:

  • Structures like verandas, balconies, or any kind of raised platform.

  • Outdoor antennae, such as a TV aerial or a satellite dish.

  • New chimneys, flues, or soil and vent pipes.

  • Any alterations to the roof structure of your existing house itself.

• Designated Areas: If your property is situated on what is defined as 'Article 2(3) designated land' (these are typically protected areas like National Parks, Areas of Outstanding Natural Beauty, or Conservation Areas), you are not allowed to apply external cladding to your extension.

• Material Harmony: The external building materials you select for your extension must visually match, as closely as possible, the materials already present on the exterior of your existing house.