11. Annex

An annex is an additional building or extension to the main property, often used for living quarters, guest accommodation, or additional storage space. It is typically self-contained, meaning it has its own living facilities such as a kitchen, bathroom, and sleeping area. An annex can be attached to the main building or stand alone as a separate structure. They are popular for providing extra space without altering the main house, and can be used for elderly relatives, grown-up children, guests, or even as a home office. 

Regulations 

According to the permitted development regulations in the UK, an annex must adhere to specific criteria to be constructed without requiring planning permission. One of these criteria is that the annex should be single-storey with no verandas, balconies, or raised platforms. 

• Single-storey requirement: This means the annex should not have more than one level or floor. This restriction helps maintain the aesthetic and structural integrity of the surrounding area and ensures that the annex does not overshadow neighbouring properties. 

• No verandas, balconies, or raised platforms: This ensures that the annex does not have elevated outdoor spaces that could infringe on the privacy of neighbours or alter the visual landscape significantly. These features could require additional scrutiny from planning authorities to ensure they do not negatively impact the surrounding environment. 

  
  

Adhering to these requirements means the annex can be built under permitted development rights, making the process simpler and faster. However, if these criteria are not met, planning permission will be needed, which can delay the construction and sale process. 

Annex size

Another important aspect of the permitted development regulations is the size of the annex relative to the land surrounding the original house. 

Maximum area limit: The total area covered by all outbuildings, including the annex, should not exceed 50% of the land surrounding the original house. This is to ensure that the property maintains a balance between built-up areas and open space, preserving the overall character of the neighbourhood and preventing overdevelopment. 

If the annex, combined with other outbuildings, covers more than half the area of the land around the original house, it would exceed the permitted development limits. This would necessitate obtaining planning permission, which involves a more detailed application process, including potentially notifying neighbours and addressing any objections.