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Home Extensions Part Two: A Guide to Planning Permission and Building Regulations

Home Extensions Part Two: A Guide to Planning Permission and Building Regulations

You may think that making the decision to invest in an extension, then researching the different extensions available to you are the key steps in transforming your home. However, with most major decisions, there is at least some red tape, and home improvements are no exception. Before you start building extensions, converting garages, or knocking down walls, you may need to get the right permissions. Here’s what you need to know.

Permitted development rights

Permitted development rights mean that you are allowed to extend your home or renovate it without having to submit a full (and often expensive and time-consuming) planning application. The last few years have seen changes in permitted development rights which mean that homeowners are able to undertake a wide range of home improvements without negotiating planning permission. These include:

Two-storey extension – until recently, this would have needed planning permission. A two-storey extension adds upstairs and ground floor space. One of the most common two-storey extensions is to double the size of the kitchen downstairs to give a large, open-plan space downstairs, and an extra bedroom or bathroom (or both) upstairs. In order to build a two-storey extension without needing planning permission, it must:

  • Be a rear extension
  • Not take up more than half of the land around the original house (including sheds and any other outbuildings)
  • Be made of materials that match the exterior of the house
  • Not go beyond 3m of the original wall, or within 7m of a boundary opposite the rear wall
  • Not be taller than the original house
  • Not be more than 3.5m higher than the next tallest terrace (for terraced properties)
  • Not have balconies or verandas
  • Not have clear or opening upper floor side windows (any side windows on the upper floor should be privacy glazed and non-opening).

Side extensions of more than one storey must have planning permission, and these rights do not apply to single-storey buildings.

A new storey – since 2020, it is possible to add a new storey to your home, providing you meet a range of caveats, including that the new storey must be no more than 3.5 m higher than the next tallest terrace.

Loft conversion – permitted rights allow you to convert your loft space and add a new dormer, up to 50m3 for detached properties and 40m3 for terraced.

Side extension – single-storey side extensions are a great way of extending your property without losing valuable garden space, as they often absorb rarely-used side alley space. If you are considering a wraparound extension to the side and rear, you will need planning permission.

Garages and outbuildings – you can usually convert a garage without planning permission, unless parking is an issue in your area, in which case there may be local restrictions (check with your local authority). Outbuildings and garden rooms offer a great way of adding space, but if you plan on using them as a bedroom rather than a gym, playhouse, office space or tv room, for example, you may need planning permission.

If you are unsure about what you are allowed to do, ask your builder or architect, or give your local authority a call. Next week, we discuss finding an architect; follow us on X or Facebook to avoid missing it.

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