Planning Permission For an Extension – 1 – Improving the Value of Your Property by Building More

Planning Permission For an Extension - 1 - Improving the Value of Your Property by Building MorePlaying by the ‘rules’

In the first of these brief articles (Understanding Planning & Property Development in the UK), we considered how you can improve the value of your property by improving the ‘quality’ of its planning permission. This showed the importance of understanding what lies behind the UK planning system and how this operates, so as to turn the ‘planning rules’ to your own advantage.

This article will look a little more deeply into those ‘rules’ that can help or hinder obtaining planning consent for an extension.

The Development Plan

Unless there are some ‘material’ planning considerations to the contrary, decisions on Planning Applications have to follow the policies set out in the ‘Development Plan’. Whatever consultations with the public, neighbours, utility companies, statutory authorities and others reveal, the decision will be guided by these planning policies and not whether your proposals are popular or not. Since the Development Plan and the Policies to which it relates have to be published, this decision cannot be arbitrary


Most kinds of structures that are considered incidental to living in and ‘enjoying’ a house, bungalow, flat, or other building are covered by the ‘planning rules’. These include most forms of outbuildings, like garages, sheds, and greenhouses. But they also apply to ancillary buildings in the garden, like tennis courts and other enclosures, ponds, swimming pools, saunas, kennels, pool houses, cabins and so on. Additional rules cover fuel storage tanks and satellite dishes as well as, of course, the building of a new house.

New Regulations Permitting Development

On 1st October 2008, new regulations came into force permitting certain types of development without the need to obtain planning permission. Even so, this requires the following guidelines for extensions to houses and bungalows to be observed. Note that flats, maisonettes and other buildings have different regulations.

· Additions or other buildings must not cover more than 50% of the land around the ‘original building’.

· Nothing should protrude in front of the main elevation or that facing a road.

· Extensions must not be higher than the highest part of the existing roof.

· Extensions to the rear of an attached house (e. g. a semi-detached or terraced house) must not be more than 3 metres. For a detached house they must not be more than 4 metres..

· A single storey extension must not be more than 4 metres high

· Any rear extension of more than 1 storey must not be more than 3 metres from the back wall, including the ground floor

· The eaves height of any extension within 2 metres of the plot perimeter must not be more than 3 metres..

· The eaves and ridge heights of any extension must not be higher than the existing.

· Any extension to the side can only be single storey, have a maximum height of 4 metres and a maximum width of 50% of the original building..

· Any 2 storey extension must be at least 7 metres away from the back boundary.

· If any extension is higher than 1 storey, the roof pitch must match the existing roof.

· Materials have to have a similar appearance to those already used.

· Verandas, raised platforms and balconies are excluded.

· Obscure glass must be used on any side windows and be at least 1.7m from the floor..

· If the land is ‘designated’ rear extensions of more than one storey, side extensions and exterior cladding are excluded.


“original’ or ‘existing’ building means that as was first built or in existence on 1 July 1948. So this means you have to take account of anything done by any previous owners since that date. ‘designated’ land is land inside national parks, the Broads, World Heritage Sites and Areas of Outstanding Natural Beauty

Passing the Two Stage Test

From the first of these articles you will recall that these address two essential questions:-

A) does this proposal constitute ‘development’ as defined by the Act? and b) if it is, does it fall under the (amended) ‘permitted development’ rules outlined above?

When you have clear answers to these questions you will know both whether you need to make a planning application at all and, if you do, how best to approach this – not forgetting the importance of checking any Local Plans and Planning Policies that may affect this. However, because of the severe title, legal and financial implications of a development not being ‘legal’, referred to in the first article, even if you think you don’t need permission it is a good idea to double check this with the Development Control Officer responsible for the area where your project is sited in your Local Authority Planning Office..

Part 2 The second part of this article will address Building Regulations, Do-It-Yourself, or Engaging Professionals, Minimising Local Authority Charges & Delays, The Building Reg. ‘Joker’, Architectural Technicians & Technologists, Feasibility ‘v – Viability, Consulting Neighbours & ‘Planners’, Making YOUR Application, LPA Procedures, Grant, Conditional Grant, and Refusal of Planning Permission, Planning Appeals, The Government’s Planning Portal, and Important Things to Remember before making your planning application. Don’t miss this important feature.

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