House Extensions without Planning Permission | Permitted Development Rights


House Extensions and Planning Permission

House extensions enable property owners to extend their living space without enhancing their property’s footprint. House extensions are relatively affordable compared to buying a new house to address space shortage. There are several types of house extensions, some falling within your permitted development rights while others require planning permission.

Homeowners and professional contractors will do their best to go around planning permission and plan a house extension that does not require approval from your local planning department. That’s because planning permission can be a time-consuming and stressful task. So, how can you build a house extension without planning permission?

Building a House Extension That Does Not Require Planning Permission

To build a house extension without planning permission, you must understand your permitted development or PD rights. These rights allow you to carry out house extensions without planning permission. The PD rights may vary according to the location of your home, the type of extension you intend to carry out, and the size of that extension.

These rights are restricted by size limits, height restrictions, design, appearance, materials of construction, impact on neighbours, and other factors. Some general conditions which apply to almost all types of house extensions include the following:

  • Regardless of the extension type, if your property is located in a conservation area, you will need approval from your local council.
  • If your home has already been extended even once, you will require planning permission.
  • Planning permission is required if you want to carry out an extension in a maisonette or flat, you will need planning permission as PD rights are only enjoyed by private properties.
  • Any extension you plan to carry out cannot exceed 50 % of your covered area.
  • The height of your extension cannot be more than the height of the highest part of your home. Not even the eaves should be higher than the existing eaves.
  • No significant roof alterations are covered under permitted development rights. The raw materials and finishing touches should match the existing roof. For any new chimneys, verandas, and even microwave antennas, you will require planning permission.
  • Side or forward extensions are not allowed on a property which is too close to the highway.

Rules for Rear House Extensions

  • If you have an attached property, your planned single-storey extension must not exceed 3 meters beyond your existing rear wall. For detached properties, this limit is 4 meters. Both these limits can be doubled, i.e. 6 and 8 meters, but you will require approval.
  • If you plan to carry out a double-storey extension, the maximum extension can be 3 meters, provided that the distance between the extended house and your rear wall is more than 7 meters.

Rules for Side Extensions

  • You can only carry out a single-storey side extension.
  • The height of the extension cannot exceed 4 meters.
  • The extension cannot be wider by more than 50 % of the width of your existing home.

Rules for Front Extensions

  • Only single-storey extensions can be carried out without planning permission.
  • Your front extension does not face any public road.
  • Your planned extension does not extend more than 3 meters from your existing home.
  • The extension width does not exceed the original width of your home by 50 % or more.

Rules for Single-Storey Extensions

  • You will not need planning permission if your single-storey extension does not exceed your rear wall by 4 meters. This applies to detached properties only. For attached properties and all other types of properties, this distance is restricted to 3 meters.
  • The height of your extension cannot be more than 4 meters.

Rules for Double-Storey Extensions

  • For both attached & detached properties, the roof pitch should be the same as your existing roof.
  • Side elevation windows on the first floor must be fixed and obscurely glazed. However, if the height of the windows is 1.7 meters, they are exempt from these restrictions.

Rules for Porch Extensions

  • The height of the porch is not more than 3 meters.
  • The porch must be at a distance of 2 meters or more from any boundary adjacent to the highway.
  • The external ground area should be at most 3 square meters.

Rules for Basement Conversions

  • Basement conversion does not require planning permission if it is not separate from your original house.
  • You don’t need planning permission if you don’t have to excavate to build a new basement.
  • If the basement conversion does not change its usage significantly, planning permission will not be required.
  • If, by the addition of a lightwell, there is no significant change in the external look of your property, you will not require planning permission.

Rules for Loft Conversions

  • Many loft conversions can be carried out without the need for planning permission.
  • If the loft’s volume after conversion does not exceed 40 cubic meters, you don’t need planning permission.
  • If the height of the dormer windows is not higher than the highest part of your existing roof, when measured from the base of the windows, planning permission is optional.
  • Dormer windows must not exceed more than the roof plane.

Rules for Garage Conversions

  • Attached garages mainly do not require planning permission.
  • Detached garages mostly require planning permission.

Rules for Outbuildings/External Structures

  • Small external structures such as garden sheds, garden rooms, and garages are often covered under permitted development rights.
  • These structures must not be erected ahead of the principal elevation.
  • The eaves must not be higher than 2.5 meters.
  • They can only be single-storey and not used for residential purposes such as bedrooms.

Rules for New Fences and Walls

New walls and fences are covered under PD rights provided:

  • They are not more than 1 meter tall if they are adjacent to the highway.
  • They are not more than 2 meters tall from other adjacent walls and fences.
  • Approval will be required for constructing walls and fences in listed buildings.

Getting Help

The above are just some rules and regulations for various house extensions and construction activities. It is always a good idea to consult your local council and construction professionals to ensure whether you require planning permission for a particular construction activity or if it falls within your permitted development rights. Knowing your PD rights can help you avoid the hassle of planning permission and reduce your costs.

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