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Extension Architecture

Planning Permission


Are You in Urgent Need to Get Planning Permission Approval?

We know what kind of proposals are most likely to be accepted, as we know the LPA planning policies. Call us and we can help. We can also tell you about any supporting statements you may need such as Design & Access Statements, Planning Statements, Heritage Reports , Transport or Noise Impact Assessments, or Flood Risk Assessments.

Our architects in London prepare professional architectural drawings for your extension plans, then submit your fee and application to the council.

Recently Approved Projects

We’ve had more than 1600 successful planning applications approved since we started to help clients turn their dream home projects into a reality. We’re very proud of our success rate and how we can cater to all your planning needs. Take a look at some examples of the projects we were granted planning permission for in this case study.

See full case study

See Our Planning Permission Case Studies


Double Storey Extension in Banstead

Date: October 2016

Project Type: Double storey rear extension, Single storey side extension, Loft conversion London.

Brief: Extension architecture were instructed to design a double storey extension to a detached house in Banstead. Our team created a rear extension to enlarge the dining / kitchen area, a new utilitynroom with skylight, larger windows and bi-folding doors to maximise natural daylight.

See Case Study

Conversion to Two Units in Ealing

Date: July 2017

Project Type: Replace double storey side / rear wrap-around extension and conversion to 2 units.

Brief: Our client’s house was on a large corner plot with a double storey side extension that looked juxtaposed with the host building. Our brief was to create a fluid cohesion on the front elevation, an in-fill extension at the rear and a conversion to two units. Existing and proposed front views.

See Case Study

First Class Extension in Tooting

Date: March 2017

Project Type: Single storey rear extension and internal reconfigurations.

Brief: This client wanted a first class extension for their rental flat which they rented out. Later they decided to move in themselves, so the spec. was altered to their bespoke preferences. The existing rear extension needed extending to accommodate their reconfiguration proposal.

See Case Study

Smart Double Storey Extension in Kingston

Date: August 2016

Project Type: House extension, Loft conversion

Brief: This client wanted a double storey extension and loft conversion. Our team created strong 3D renders as visuals. Our planning consultants decided the best route for his chances of approval was to submit two the separate applications.

See Case Study
render for article on reconfiguration in leafy conservation area

Reconfiguration in Epsom

Date: June 2017

Project Type: Loft conversion and first floor rear extension.

Brief: This client wanted a loft conversion, first floor rear extension and internal reconfiguration to add a bedroom to their large semi. Because it the house is considered a ‘positive’ building in conservation and next to a listed building, we could not alter the roof pitch or height.

See Case Study

Extension and Landscaping in Sutton

Date: February 2017

Project Type: Single storey rear extension and landscaping.

Brief: This family was a referral from one of our flagship project clients, for a single storey in-fill extension, internal reconfiguration on two floors, garage conversion and landscaping. We created a stunning new extension and stepped garden design for them.

See Case Study

Extension & Loft Conversion, Kingston

Date: September 2015

Project Type: Double storey rear extension, Loft conversion.

Brief: The proposal was to redesign and modernise this detached house. To comply with the Council’s planning regulations, our designers used a sensitive approach regarding the existing materials and form to preserve the character of the local residential architecture.

See Case Study

Double Storey Extension in Croydon

Date: April 2017

Project Type: Double storey extension.

Brief: We were appointed to extend this semi-detached house in South Norwood to create a large dining and kitchen area for their busy family lifestyle. The planning approval was facilitated by a precedent which had been set by a neighbour who added two storeys.

See Case Study
Neighbouring Precedent

Terrace Planning Permission

We were approached to submit a proposal which looked to maximise an upper level flat, giving it valuable outdoor space by creating a roof terrace. Located in a Conversation Area and with direct views to the back neighbours…

See Case Study

Planning Permission

Preferred Planning Strategies

Following the initial site assessment (which can be conducted remotely to be efficient), a site survey would be carried out to gather all the existing dimensions and a photographic survey to document the existing site. Usually within 1-2 weeks, the initial drawings are prepared with options for the client to consider and can be discussed with our consultants for the best proposal. We always ensure communication with the clients liaising with them the optimised design solutions, amending drawings to the client’s feedback but making sure that they are feasible for planning application. Once everything is finalised and approved by the client, the application will be submitted to the local authority.

Before undertaking a design project we would assess the history and context of the site and its surroundings. We research the local planning authority and establish what planning applications previous neighbouring properties have proposed, either accepted or refused. We also examine whether the property is under a Conservation Area, a listed building or within a floor risk zone. These factors would affect the planning applications and additional documentation is required to supplement the proposal. However, such constraints we would guide the client appropriately.


Does your extension need Planning Permission?

This will be determined by factors like the size of your build, the Permitted Development rights which apply to your property, and whether you live in a conservation area. Whilst the application process can be daunting, this guide will give you information for a single storey extension, and we can help with your house extension London plans and whether you need conservatory planning permission (or loft conversion planning permission).

What do applications require?

Full Planning Applications include:

  • All existing drawings of the property (floor plans, elevations, sections)
  • All proposed drawings (floor plans, elevations, sections, site plans)
  • A detailed Design and Access Statement (if required)
  • Heritage Statement, Flood Risk Assessment, Arboricultural Report etc (we will advise if these are required for your planning applications)
  • Site plan and block plan, Ordnance Survey Map
  • Application forms, Notification letters, CIL Questions

What happens if neighbours have objections to planning permission?

It is lawful for planning applications to be decided according to development policy, unless there are contra-indications with material considerations. Application decisions are therefore policy-led, as opposed to influence-led. Near neighbours and the public will be consulted in most cases, but the result of the application will not be decided via popularity or grievance. Planning policies prevent results being decided by arbitrary, perverse or improper factors.

Do have a talk with the neighbours about your proposal. They will be consulted by the Local Planning Authority anyway, but only material considerations will be used.

If there are no objections, it won’t need to go to a Planning Committee, but rather will be approved using delegated powers. We recommend that you contact them early so that planning applications can be submitted along with a letter of support from them.

We recommend drafting a letter of support for them to sign or rewrite. Including details about your meetings with them and how you have included their views. A letter such as this will prevent the application from focusing too deeply on local disputes, allowing the officer to focus on the technical side of the proposed development.

Objections that do not affect planning permission

  1. The loss of any private views
  2. Legal matters which are personal and private, like right of way, boundary disputes or contracts
  3. Whether your project will raise or lower a property’s value
  4. The possibility of any future development
  5. An agenda from the applicant, such as profit
  6. An applicant’s personal behaviour, or business operations
  7. Inconvenience caused during the building process
  8. Competitive issues with similar business within mutual proximity
  9. Morals or religion
  10. Aspects already covered by other legislation, such as environmental health, party walls or building regulations
  11. Additional legislative details like Party Wall protocols, Building Regulations and environmental health

Of course, if you can settle any disputes amicably, this will help to expedite the process.

How Material Considerations affect applications

Local Authority Planning Departments base their decisions on material considerations. This can be complex since what defines a material consideration is not specified in law. Moreover, not every material consideration applies to each project. The most common material considerations which might impact applications are:

Appearance, materials & design

Design covers things like dimensions, shape, proportions, materials, style and finish of a building. Acceptable design is subjective and variable. With respect to material considerations, the design should fit its surroundings by following, reflecting or tastefully contrasting the design of adjoining buildings.


If an area contains an archaeological site, it may be protected. It may not result in a refusal, but the site will normally require excavation before work starts. The developer should also take extra care with the work site.

Density of the building & layout

The proposed scale and design of a new build should match the existing site with respect to the nearby buildings, retaining the character of the area. The amount of space round a build is also important, as well as where it sits within the plot. Following the pattern of the area in this respect also defines the character of an area.

Development benefits

Sometimes the benefits of a proposal outweigh local or policy objections. This clearly is a positive material consideration.


The planning authority will consider the impact of new proposals on trees and plant life, and wildlife, especially with any protected species (such as otters.)

Green Belt

green belt map for article on Planning Permission for Extension

In green belts, most new builds will be viewed as inappropriate, so material considerations will be very restrictive. However, there is a limited set of acceptable development criteria in the NPPF (National Planning Policy Framework). Here are the criteria:

  1. Agricultural and forestry buildings
  2. Outdoor sports facilities and, providing that open spaces and green belt purposes remain unaffected, outdoor recreation and cemeteries.
  3. Extensions and alterations to existing buildings, provided they do not result in disproportionate additions to the scale of the original property.
  4. You can replace existing buildings, provided the new building does not mean a change of use, and is not larger than the previous building
  5. Limited housing for the local community and limited infilling of properties in villages so long as they follow the policies in the Local Plan
  6. Limited infilling or partial or complex redevelopment of brownfield sites which are either redundant or in continuing use (not including temporary buildings), so long as open space and green belt purposes remain unaffected.

At Extension Architecture, we have good experience with several interesting projects located in Green Belts.

Parking & access

The noise of cars in parking places and access drives can constitute a material consideration, especially if the development is adjacent to existing residential properties with gardens. Highway safety will be considered, adequate physical access parking provision and turning space. Councils vary re parking requirements, for example the amount of off-street parking required is reduced if there are good public transport links, adequate road parking or public car parks.

Permitted Development

Another Material Consideration that will also be weighed by the local Planning Department is the level of permitted development rights in the area. For further reading on Permitted Development, see our article on Permitted Development, or call us if you would like a Permitted Development extension.

Physical factors

What this means is which buildings or obstacles are currently present. It is also the underlying ground conditions, and mapping & charting of the site as per existing topography. These can influence or constrain the preferred position of a proposal within a site. In addition, access to local services and amenities are common material considerations.

Planning history

This Material Consideration is a search of past approved permissions, refusals and appeals in the immediate area.


Even though planning history is considered, each case has to be looked at on its individual merits. Planners should be fair and consistent when applying their policies.

Residential amenities

Even though planning history is considered, each case has to be looked at on its individual merits. Planners should be fair and consistent when applying their policies.

Risk of flooding

Applications for new builds in vulnerable areas are likely to be unsuccessful, unless there are no other options outside the risk zone.

Special designations

The new build may possibly impact on areas of outstanding natural beauty, conservation areas or listed buildings. Buildings, views and open spaces contribute to an area’s character, which is quite a big material consideration. Planners try to protect listed buildings, whilst the law protects conservation areas.

Support / opposition level

If public opinion lends weight to a subjective judgement, such as on its design merits, then this will be a material consideration.

Dealing with Local Planning Authorities

How can I identify my Local Planning Authority?

If you are in doubt about who is your exact local planning department, consult the UK Govenrment website and enter your postcode to get information on your LPA.

Variations between Local Planning Authorities

We know what kind of proposals are most likely to be accepted, as we know the LPA planning policies. Call us and we can help. We can also tell you about any supporting statements you may need such as Design & Access Statements, Planning Statements, Heritage Reports , Transport or Noise Impact Assessments, or Flood Risk Assessments.


What happens after my planning application is submitted?

After your application has been submitted, Local Planning Authority procedure can be seen in the following chart, which includes details of how to proceed, should the application be refused:

chart for article on Planning Permission for Extension  

After your planning submission has been validated, the LPA will post all the documents and drawings onto its website for the public to view. They also begin consulting regarding your case to inform parties with interest of your intended development. They talk to:

  • Neighbouring residents
  • The Parish Council
  • Stakeholders
  • In-house professionals
  • External Professionals

In this way they gather technical expertise and advice for them and for you. The application must run for eight weeks so that all parties have an opportunity to respond.

After six weeks, when all the feedback is in and after their site visit, the officer puts all their findings together with the relative planning policies and any relevant material considerations. After internal discussions they will write a recommendation for either approval or refusal. This will include conditions like working hours for the build or pre-build approval of materials. These will need to be agreed formally before building can start.

Deciding your application can be done by officers or the Planning Committee which is a small body of councillors. Simple cases are taken by officers but any controversial ones go to the committee. You can request that your application goes before the committee if you are not happy with the usual route. You may be able to lobby councillors ahead of the Planning Committee meeting and even participate as a speaker. This is quite a good idea because they are not bound by the recommendations of planning officers.

Planning Application FAQ

Q: What are planning decisions based on?

  • Local Planning Authority development policy and material considerations
  • Many factors relate to land development, although private matters do not
  • See your local neighbourhood plans for relevant development policies

What is the neighbourhood plan?

This is the plan intended to give best policy to the local community via consulting the people who use the area, from its residents to businesses, stakeholders and local MPs. These plans are the first policy documents a Local Planning Authority will consult. They are made up of written policies, explanations and proposal maps covering issues such as:

  1. Area-specific issues
  2. Community
  3. Countryside
  4. Design
  5. Development Control Criteria
  6. Employment
  7. General Strategy
  8. Green Belt
  9. Heritage
  10. Housing
  11. Sustainability
  12. Tourism & Leisure
  13. Transport

Can my time limit be extended?

It is lawful for your permission to run out after three years, except where you have made a substantial start such as completing your foundations. However if you have not begun the build and the three years is nearly up, you will usually have to make a new application.

Could I change my design a little after getting approval?

Minor alterations are permissible if you apply for a non-material amendment, but larger alterations might need a further application. Your local planners decide whether the amendment is large or small.

What can I do when planning permission is denied?

75% of householder applications are granted in England, although this varies a lot from council to council. If you are refused, we can address the reasons with an amended re-submission, or you can appeal to the Planning Inspectorate. About 35% of appeals are granted. Listed building or conservation area decisions, attached conditions, enforcement notices or non-determination can be challenged (when it was not decided within the required limit.) The appeal can be in writing, hearing or public enquiry. Call us for guidance.

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