Appeal 3270994
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Official decision document
The decision, section by section
10 sections
Read the development description and the Inspector’s text from the official decision PDF in source order. Source headings are retained where available. Personal and contact details are removed by an automated privacy filter; this is source material, not Rules for You analysis.
Section 01
Development description
the demolition of single storey flank extension and erection of reduced width two storey flank extension together with Dormer windows and internal alterations.
Section 02
Decision
The appeal is allowed and planning permission is granted for the demolition of single storey flank extension and erection of reduced width two storey flank extension together with Dormer windows and internal alterations at [site address] , [site address] , Ash [postcode] in accordance with the terms of the application Ref 20/03495/HOUSE, dated 25 November 2020, subject to the conditions set out in the schedule to this decision.
Section 03
Procedural matter
An application for costs was made by the appellant against the Council. This application will be the subject of a separate decision.
Section 04
Main issue
The site lies within the Green Belt. The main issue is whether or not the proposal would be inappropriate development in the Green Belt having regard to the National Planning Policy Framework (the Framework) and relevant development plan policies.
Section 05
Reasons
The proposal is primarily to erect a two-storey extension at the side of [site address] , which is a detached dwelling set back from the road within a generous plot with good sized gardens. The existing single storey side projection with a flat roof and external steps would be demolished and removed to make way for the new addition.
The submitted plans also show that a small dormer would be placed onto the front roof slope of the main house. A short flat roof above the front entrance would also be replaced with a pitched roof supported by timber posts to form an open-sided porch.
Section 06
Whether inappropriate development
The Framework states that the construction of new buildings in the Green Belt is inappropriate. Exceptions to this are listed in paragraph 149, which include the extension or alteration to existing buildings provided it does not result in disproportionate additions over and above the size of the original building (criterion c). The Framework does not define the term disproportionate.
Policy GB1 of the Council’s Allocations and Development Management Plan (ADMP) notes that extensions to an existing dwelling should, amongst other things, be proportional to the original dwelling (criterion b). It also adds that for extensions to be acceptable, the total floor space of the proposal, together with any previous extensions, alterations and outbuildings, should not result in an increase of more than 50% above the floor space of the original dwelling (criterion c). The Council’s Supplementary Planning Document, Development in the Green Belt, (SPD) echoes these requirements.
The Council has accepted that it determined the size of the original dwelling with reference to the planning history of the wrong property. Given this admission, I am unable to place any reliance on the estimates of floor area set out in the Officer’s report or its numerical assessment of proportionality. That is because the starting point of the exercise, which is to establish the size of the original building, is incorrect.
In its subsequent analysis, the Council states that it considers that the single storey flat roof element at the side of the existing dwelling is not original, which is based on a review of its internal historic mapping system. It also reflects the Council’s observations that the windows, brickwork and roof form of the existing single storey side projection noticeably differ to those of the 2-storey house. The appellant appears to share this opinion and, from my inspection of the building, so do I.
The Council appears to conclude, therefore, that the building, as it currently stands, is not original although it has provided few details to support this assertion. That ambiguity may be due, in part, to the Council’s record of the site’s planning history, which it says are incomplete with the plans accompanying the grant of planning permission1 for the erection of a dwelling on the site missing. The appellant states that the dwelling on the site was originally constructed as a chalet bungalow with first floor bedrooms and a bathroom, which is supported in correspondence from a relative of the original builders. There is no indication of the building’s size as originally built at that time.
From what I saw, the 2-storey element of the existing building visually ‘reads’ as a single and largely cohesive entity, with no obvious sign of significant enlargement aside from the single storey flat roof side projection, which is to be replaced. On that basis, and in the light of the submissions made by both parties, I consider that the 2-storey house should be regarded as the original building for the purpose of this assessment. 1 Application Reference T/5/55/128
There are no reliable estimates of floor area before me in relation to the existing building, as a whole or in part. Nevertheless, a visual comparison between the proposed 2-storey extension and the 2-storey host building, as shown on the plans, indicates that the new addition is unlikely to exceed the 50% size threshold identified under ADMP Policy GB1 (c). Given their modest size, the addition of a new front dormer and an open sided porch, as proposed, would not alter my finding on this point.
The Officer’s report also refers to the Council’s recent decision2 to approve a single storey flat roof extension following the demolition of existing conservatory. Few details of this scheme have been provided and it is unclear whether or not it will come forward. Even if it did in combination with the proposal before me, I doubt that the cumulative effect would be so great as to result in the existing 2-storey building increasing in size by more than one half.
Taking all of the above points into account, I conclude on the main issue that the proposal would not constitute a disproportionate addition over and above the size of the original building. Therefore, the new development falls under the exemption listed in paragraph 149 (c) of the Framework. On that basis, it is not inappropriate development in the Green Belt and there is no conflict with ADMP Policy GB1 or the Council’s SPD in that regard. As a result, a consideration of the need to demonstrate very special circumstances to justify the development is unnecessary.
Implicit in my finding on this main issue is that the proposed development should not be regarded as harmful either to the openness of the Green Belt or to the purposes of including land within it. To that extent, ADMP Policy GB1 (b), which additionally requires that extensions do not materially harm the openness of the Green Belt, is out of step with the Framework. Because the Framework reflects current Government policy, I place greater weight on it for the purpose of this appeal.
Section 07
Other matters
The proposed extension would result in a dwelling with wider 2-storey front and rear elevations. Even so, the proposal would be a proportionate addition. With the removal of the long single storey side element, which contributes little positively to the appearance of the house, the proposal would introduce greater balance to the finished dwelling with the existing 2-storey forward projection more centrally placed in the front façade. Having regard to the overall size and mass of the completed dwelling, the new 2-storey extension would not appear overly large, bulky or visually intrusive. Combined with the use of matching external materials and a consistent pattern of fenestration the proposal would relate well to the host building. It would be a sympathetic addition.
To my mind, the proposal achieves the standard of design sought by the Framework with a cohesive style across the finished building, unlike the existing property with its incongruous single storey side projection. These outcomes would not necessarily be achieved if the new extension were to be designed as a subordinate element to the original house. In those circumstances, a conflict with ADMP Policy GB1 (b), which states that extensions should be subservient to the original dwelling, is insufficient in itself to withhold planning permission. 2 Application Reference 20/02730/LDCPR
Section 08
Conditions
In addition to the standard time limit condition, I have imposed a condition specifying the relevant drawings and to require that the development is carried out in accordance with them as this provides certainty. To ensure the satisfactory appearance of the building, a condition is imposed to require that the external materials match those of the existing building.
A condition that removes some permitted development rights is justified to maintain the openness of the Green Belt and to ensure that the appearance of the development is satisfactory. These conditions reflect those suggested by the Council with minor changes made for clarity.
Section 09
Conclusion
For the reasons set out above and having regard to all other matters raised, I conclude that the appeal should be allowed.
Section 10
Schedule of conditions
The development hereby permitted shall begin not later than three years from the date of this decision.
The development hereby permitted shall be carried out in accordance with the following approved plans: Refs 1, 2 and the Location Plan that shows the site edged red.
The materials to be used in the construction of the external surfaces of the development hereby permitted shall match those used in the existing building.
Notwithstanding the provisions of the Town and Country Planning (General Permitted Development) Order 1995 (or any order revoking or re-enacting that order), no development (as defined by Section 55 of the Town and Country Planning Act 1990) as may otherwise be permitted by [name] to E (inclusive) of Part 1 of Schedule 2 of the Order shall be carried out.
Planning inspector and document dates
The official casework attribution is grouped under a one-way keyed hash and shown only by its local identifier. Decision-letter dates and page references are extracted by fixed first-page rules and checked against that authoritative record.
Costs Decision
- Extracted inspector · page 1
- Inspector attribution ID 287No official casework-database value to compare
- Extracted decision date · page 1
- 12 October 2021Matches the official casework database
- Extracted site visit dates
- 23 September 2021 (page 1)
Appeal Decision
- Extracted inspector · page 1
- Inspector attribution ID 287No official casework-database value to compare
- Extracted decision date · page 1
- 12 October 2021Matches the official casework database
- Extracted site visit dates
- 23 September 2021 (page 1)
Reference and authority
Official identifiers and the planning authority recorded against this case.
- Case reference
- 3270994
- Application reference
- 20/03495/HOUSE
- Lead case reference
- Not recorded
- Planning authority
- Sevenoaks District Council
- Planning authority code
- E07000111
Casework details
The casework, procedure, development and linking details supplied by the official record.
- Casework type
- Householder (HAS)
- Procedure
- Written Representations
- Development type
- Householder developments
- Appeal type reason
- 1. Refused planning permission
- Appeal reason
- Refusal
- Type detail
- Planning Appeals - Full
- Jurisdiction
- Transferred
- Link status
- Not Linked
Site and development
Published appeal-site measurements and planning designations, without the withheld precise location fields.
- Site area
- Not recorded
- Floor space
- 174 m²
- Number of residences
- 0
- Site in Green Belt
- Yes
- Agricultural holding
- No
- Affects setting of a listed building
- No
- Historic building grant made
- No
- Relates to a conservation area
- No
- Flooding is an issue
- No
- Site within an AONB
- No
- Site within an SSSI
- No
Decision and dates
The published outcome and every imported case date.
- Official decision
- Allowed
- Decision category
- Allowed
- Received date
- 15 March 2021
- Valid date
- 15 March 2021
- Start date
- 13 May 2021
- Planning authority decision date
- 1 February 2021
- Appeal decision date
- 12 October 2021
Case administration
Published recovery, call-in, costs and enforcement information for this case.
- Redetermined
- No
- Bespoke
- No
- Date recovered
- Not recorded
- Date not recovered or derecovered
- Not recorded
- Call-in date
- Not recorded
- Costs applied for
- No
- Enforcement grounds count
- Not recorded
- Enforcement grounds
- Not recorded
Source and catalogue history
When this record appeared in the rolling official release and when the catalogue stored it.
- Source
- Planning Inspectorate casework database
- Source data system
- Horizon
- Dataset status
- Current release
- Catalogue record ID
- 4514
- First seen
- 20 August 2026 at 14:24
- Last seen
- 20 August 2026 at 16:25
- Removed from release
- Not recorded
- Record created
- 20 August 2026 at 14:24
- Record updated
- 24 August 2026 at 16:21