Appeal 3358425

The appeal is allowed and planning permission is granted for demolition of existing outbuilding and construction of single storey front extension and part single, part two storey side and rear extension at [site address] , [site address] , Heronsgate, Hertfordshire [postcode] in accordance with the application, Ref 24/1624/FUL, subject to the following conditions:

The development hereby permitted shall begin not later than three years from the date of this decision.

The materials to be used in the construction of the external surfaces of the development herby permitted shall match those used in the existing building.

The development hereby permitted shall be carried out in accordance with the approved plans: 50241/A, 5024/2A, 5024/3D, 5024/4F and 5024/5B.

The site visit was undertaken by a representative of the Inspector whose recommendation is set out below and to which the Inspector has had regard before deciding the appeal.

I have taken the description of the proposed development from the decision notice and appeal form as it more accurately describes the proposals.

The main issues in the appeal are: • Whether the proposal would be inappropriate development in the Green Belt having regard to the National Planning Policy Framework (the ‘Framework’) and the development plan; and • The effect of the proposal on the character and appearance of the host dwelling and the Heronsgate Conservation Area (CA).

The appeal property is a detached, two storey dwelling. The dwelling is set within a spacious plot, accessed via a driveway. It is proposed that one of the existing outbuildings located close to the dwelling would be demolished and that new extensions should be added to the house, namely a single storey front extension and a part single, part two storey side and rear extension.

Paragraph 154 of the Framework states that new buildings are inappropriate in the Green Belt unless they fall within the given list of exceptions. One exception is the extension or alteration of a building provided that it does not result in disproportionate additions over and above the size of the original building.

Policy CP11 of the Local Development Framework Core Strategy (adopted 17 October 2011) (the ‘[name]) is generally consistent with the Framework relating to the Green Belt. It refers to the pressure on the Green Belt within the District and Policy CP11 emphasises the general presumption against inappropriate development. Policy DM2 of the Development Management Policies Local Development Document (adopted July 2013) (the ‘LDD’) states that extensions to buildings in the Green Belt that are disproportionate in size (individually or cumulatively) to the original building will not be permitted. The building’s proximity and relationship to other buildings and whether it is already, or would become, prominent in the setting and whether it preserves the openness of the Green Belt will be taken into account.

Neither the Framework nor the development plan provide a definition of ‘disproportionate additions’. However, some guidance is provided in the Supplementary Planning Guidance No.3, Extensions to Dwellings in the Green Belt which states that extensions resulting in a cumulative increase in floor space of over 40% compared with the original dwelling may be disproportionate. The Council have confirmed that although this document relates to Green Belt policies of the Three Rivers Local Plan 1996-2011, which have now been superseded by Policy DM2, the general threshold of 40% is still used as a guide.

The Council and the appellant have provided differing figures in relation to how much the extensions increase the floor area of the original building (33% and 31% respectively). Whichever calculations are taken, the proposal would represent an increase in floorspace below 40%.

Although there will be an increase in overall bulk from the proposals, the additions are proportionate and not out of keeping with the scale of the original dwelling and plot size. The design responds to the form of the original building, with the central part of the house becoming moderately wider, maintaining the same ridge height and a further side extension stepping back from the front of the property and a lower ridge height maintained. The front and rear extensions would be subordinate to the host dwelling. I therefore do not consider that the proposed extensions would represent a disproportionate addition over and above the size of the original building.

For these reasons, I find that the proposal would not comprise inappropriate development within the Green Belt as defined by the Framework and Policy CP11 of the Local Plan and Policy DM2 of the LDD.

The appeal site is located within the [name]. I have therefore had regard to Section 72 of the Planning (Listed Buildings and Conservation Areas) Act 1990 (the Act) which places a duty upon the decision-maker, in the exercise of planning functions, to have special regard to the desirability of preserving or enhancing the character or appearance of conservation areas. The Framework further advises that when considering the impact of a proposed development on the significance of a designated heritage asset, great weight should be given to the asset’s conservation.

The Heronsgate CA is made up of large individual houses, high quality landscaping and a rural setting with plentiful hedgerows and trees. The significance of the CA is derived from its historical association with the Chartist movement which sought to provide self-sufficiency and improved conditions through the provision of homes within large plots linked by narrow lanes.

The appeal property is a large dwelling with a spacious garden, it is set back and well screened from [site address] and neighbouring properties by mature hedges. The appeal property is noted as being a newer house in the Heronsgate Conservation Area Appraisal (April 2012). It is built in an Arts and Crafts style and its attractive design makes a positive contribution to the special interest of the CA.

I consider the extensions to the dwelling will be proportionate and not out of keeping with the scale or form of the original house, garden or neighbouring properties. Whilst the side extension does elongate the house, it remains subservient in scale compared to the main part of the dwelling with its lower ridge height and the set back from the front of the house.

Importantly, the design has sought to preserve original Arts and Craft features, including the distinctive angled wall with round windows at the front of the property. Whilst the relative position of the chimney on the roof will change, it has been retained and can still be appreciated as part of the design.

The front porch of the dwelling will be extended across the full width of the central section of the house. Whilst the increase in size will change the character of the porch, its design reflects that of the original porch, complementing the style of the property. Given the overall proportions of the dwelling, its scale and design would not appear to overly dominate nor be out of keeping.

For these reasons, the proposed development would not have a harmful effect on the character and appearance of the host dwelling and would preserve the character and appearance of the CA in accordance with Section 72 of the Act. The proposal would accord with the Framework and Policy CP1 and CP12 of the [name] which seek to encourage good design and conserve and enhance heritage assets. It would also accord with Policy DM1 and Appendix 2 of the LDD which address design considerations generally and Policy DM3 which includes provisions relating to conservation areas and seeks to ensure development preserves or enhances the character or appearance of the area. The proposal would also accord with guidance in the Heronsgate Conservation Area Appraisal (2012).

I have considered the conditions suggested by the Council. Where necessary, and in the interests of clarity and precision, I have slightly altered the conditions to better reflect the advice in the Framework and the Planning Practice Guidance.

I have imposed the standard conditions relating to the commencement of development and specifying the relevant plans in order to provide certainty. I have included a condition requiring the external materials to match the existing building to protect the character and appearance of the appeal property. The appeal site is well landscaped and verdant in character and the proposed extensions are discreetly located and set back from the boundary of the property away from public view. In these circumstances, a condition requiring a scheme of replacement planting to be submitted as suggested by the Council is not necessary to make the development acceptable in planning terms.

For the reasons given above, the proposal would comply with the development plan when taken as a whole and there are no material considerations, including the Framework, that would outweigh this finding. Consequently, I recommend that the appeal should be allowed.

I have considered all the submitted evidence and my representative’s report and on that basis the appeal is allowed.