Extension Samples


With a long history of building extensions to a vast array of property types, CFBD's expertise in this field is widely known.

Successful project management ensures that a family can continue to use their home throughout the works and an understanding of what can and cannot be done, both legally and physically, means that the home owner gets a surprise-free construction and a beautiful, home-changing addition to their property. Our design team will help you understand how a space becomes most beneficial, the importance of light and of course the most cost effective and productive means of tailoring this knowledge to suit your home.

The legislation around home extensions varies depending on property type and area but in general, the following applies;

Extensions: What you can do without planning permission

  • You can extend a dwelling by 4m to the rear if it's single storey or 3m if it's double.
  • There are height restrictions but they boil down to a single storey extension not being higher than 4m in height to the ridge and the eaves, and ridge heights of any extension not being higher than the existing property.
  • Two storey extensions must not be closer than 7m to the rear boundary.
  • It must be built in the same or similar material to the existing dwelling.
  • Extensions must not go forward of the building line of the original dwelling.
  • Side extensions must be single storey, maximum height of 4m and a width no more than half of the original building.
  • In Designated Areas side extensions require planning permission and all rear extensions must be single storey.
  • An extension must not result in more than half the garden being covered.
  • You can only do it once and the original building is either as it was on 1st July 1948 or when it was built

Outbuildings: What you can do

  • You can construct all sorts of outbuildings for the use and enjoyment of the home so long as they do not cover more than 50% of the garden space. In Scotland this is reduced to 30%.
  • In Wales and Northern Ireland any outbuildings closer to the house than 5m count as extensions. In Scotland any outbuildings larger than 4m2 and closer to the dwelling than 5m count as extensions.
  • Outbuildings must be single storey with a maximum ridge height of 4m for a pitched roof or 3m for any other kind of roof. The eaves height must be no more than 2.5 metres.
  • If the outbuilding is closer to the boundary than 2m it shall be no higher than 2.5m.

Did you know...?

Balconies, verandas and raised platforms (above 300mm) do not fall under PD rights. You will also now need planning permission to construct a drive from non-porous materials such as tarmac. But you can construct a new drive of porous materials, or non-porous if provision for drainage is provided on the property, under PD.

Note: The government recently announced that it intends to relax permitted development rules relating to extensions for a year long trial period. The new rules are likely to mean that for single storey rear extensions the limit will be 8m for a detached house and 6m for a semi or terraced house; in effect a 100% increase in the permitted amount. It is important to remember though that these changes have not yet come in to effect and hence current limits still apply.


"I have to thank you for all you hard work and commitment to the project"… Dr Ayoubi, Harley St

We at CFBD enjoy a good natter about the weather as much as anybody; its an identifiably English thing and helps other less boring nationalities spot us from a safe distance.

This week however has been particularly character building in terms of how we are all affected by different weather.