Existing cellar floor to be lowered to convert into bedroom, with improved means of fire escape from lower levels through new lightwell in existing courtyard of residential building not visible from the public highway. Replacement of existing single glazed windows with new double glazed units to increase energy efficiency and improve the look of the building

Appeal Decision Site visit made on 1 July 2026 by Rachel Hall BSc MSc MRTPI an Inspector appointed by the Secretary of State Decision date: 22 July 2026. Appeal Ref: 6002721 8 The Mezzanine, West Grove, Greenwich SE10 8QT • The appeal is made under section 78 of the Town and Country Planning Act 1990 (as amended) against a refusal to grant planning permission. • The appeal is made by Mr Matthew King against the decision of the Council of the Royal Borough of Greenwich. • The application reference is 25/1956/HD. • The development proposed is described as ‘existing cellar floor to be lowered to convert into bedroom, with improved means of fire escape from lower levels through new lightwell in existing courtyard of residential building not visible from the public highway. Replacement of existing single glazed windows with new double glazed units to increase energy efficiency and improve the look of the building’. Decision 1. The appeal is allowed and planning permission is granted for existing cellar floor to be lowered to convert into bedroom, with improved means of fire escape from lower levels through new lightwell in existing courtyard of residential building. Replacement of existing single glazed windows with new double glazed windows at 8 The Mezzanine, West Grove, Greenwich SE10 8QT in accordance with the terms of the application, reference 25/1956/HD, subject to the conditions in the attached schedule. Application for costs 2. An application for an award of costs was submitted by Mr King against the decision of the Council of the Royal Borough of Greenwich. This is the subject of a separate decision. Preliminary Matters 3. As the proposal is in a conservation area and relates to a listed building I have had special regard to sections 66(1) and 72(1) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (as amended) (the Act). The submitted appeal only relates to the refusal of an application for planning permission. No listed building appeal is before me. 4. The Council did not identify any harm in respect of the effect of the proposal on the character or appearance of the West Greenwich Conservation Area. Given the modest scale of the proposal and lack of prominence from the public realm, I see no reason to conclude otherwise and find that the character and appearance of the West Greenwich Conservation Area would be preserved. 5. In light of the Council’s comments in the officer report regarding inconsistencies and inaccuracies in the submitted plans, the appellant submitted revised plans with Appeal Decision 6002721 2 the appeal. These comprise drawing nos. 25 0110-8 C and 25 0110-9 C. A 3- dimensional image of the external staircase and lightwell was also included. Also, a new Basement Impact Assessment by Seymour Building Services (2 October 2025) (BIA) was submitted along with an Arboricultural Impact Assessment by Plumb Associates (October 2025). The Council was given the opportunity to comment on these and any comments have been taken into consideration here. Accordingly, I consider no party has been prejudiced in determining the appeal on the basis of the minor revisions to the submitted plans and updated supporting information. 6. The description of development in the decision above is the same as that used in the heading above, but with some words omitted where they are superfluous (relating to its visibility from the public highway and the intention to increase energy efficiency and improve the look of the building). Main Issues 7. The main issues are: • whether it has been demonstrated that the proposal would preserve a Grade II listed building known as “7 and 8, West Grove SE10” (Ref: 1212184) (the LB), or any of the features of special architectural or historic interest that it possesses; • whether the proposal would be acceptable with respect to its impact on trees; and • whether the proposed basement and lightwell would be acceptable with regard to impacts on pollution and flood risk and the living conditions of neighbouring occupants with particular regard to noise. Reasons Listed Building 8. The listed building comprises Nos 7 and 8 which are adjoining early 19th century houses of four storeys and sunk basements. They are comprised of multicoloured stock brick with banded rusticated stucco at ground floor and a parapet concealing the roof. A single storey building is situated to the rear of No 8, comprised of stock brick with a flat roof (Garden Cottage). The proposal relates to a further outbuilding situated beyond Garden Cottage at the rear of the site. It is also comprised of stock brick and has a flat roof. 9. Given the above, I find that the special interest of the LB, insofar as it relates to this appeal, to be primarily associated with the architectural interest of the main house as an example of a high status Georgian terraced building. The presence of the appeal outbuilding also contributes to its significance due to its surviving historic fabric and subservient form, reflective of the status differentiation between the main house and its outbuildings. 10. The proposal is for excavation of the cellar to create additional headroom so that it can be used as a bedroom. In addition, a new lightwell is proposed to be excavated in front of the appeal outbuilding, with a fire escape window and external staircase to be added. The existing single glazed windows are proposed to be replaced with Appeal Decision 6002721 3 double glazed casement windows. Also, the existing front door is proposed to be replaced. 11. It is not a matter in dispute that the existing windows date from the mid 20th century. As such, I find that their replacement with black Crittall-style windows would be acceptable, without harm to the building’s significance as an outbuilding to a Georgian terraced building. The existing front door is also described as mid 20th century and therefore is not contemporary with the LB. The Council objected to its replacement with a composite door. However the appellant has provided details of an alternative timber door. Subject to details of this being approved by condition I consider this element of the proposal would be acceptable without harm to the special interest of the LB. 12. The Council’s conservation officer response raised concerns about the lack of information on the effect of the basement excavation on the structural stability of surrounding heritage assets. In particular, that structural engineer’s drawings and specifications and a ground-movement impact assessment should be provided prior to determination. However, the proposed excavation would be limited to that of the proposed modest sized lightwell, and the lowering of the existing cellar floor by 1000mm, with the existing cellar only occupying part of the footprint of the building. Details have been provided of how it is anticipated that the building would be underpinned. Moreover, the updated Basement Impact Assessment (by Seymour Building Services) confirms that the proposed works would be carried out in accordance with the relevant building control regulations and approvals, including in respect of structural calculations and soil investigation in consultation with the appointed structural engineer. 13. Given the modest scope of the proposed excavations, I am satisfied that a condition requiring details of measures to ensure the structural stability of the host building and neighbouring historic features would be effective. Therefore, the proposed excavations would not give rise to harm to the historic appeal outbuilding or other heritage assets. The Council’s Urban Design Guide Supplementary Planning Document (October 2023) (SPD) states that basement extensions are not supported for listed buildings. However, in the particular circumstances of this case, which relates to a limited extension to a modest outbuilding, the proposed extension would nonetheless be acceptable and would not undermine the historic hierarchy of the outbuilding relative to the main house. 14. Given the above, and in light of the updated drawings that have addressed previous drafting inaccuracies, I find that the proposal would preserve the special historic interest of the LB. This would satisfy the requirements of the Act and paragraph 210(a) of the Framework. It would also comply with Policies D3, HC1 and HC2 of the London Plan (2021) (London Plan) and Policies DH1, DH3, DH(h) and DH(i) of the Royal Greenwich Local Plan: Core Strategy with Detailed Policies (2014) (Core Strategy). Together these generally seek to ensure that proposals are designed having regard to the character of their surroundings, including the historic environment. Trees 15. The submitted Arboricultural Impact Assessment (the AIA) confirms that the only tree in the vicinity of the appeal scheme is a small apple tree adjacent to the wall that encloses the courtyard. Given the proximity of the tree to the wall, its roots are Appeal Decision 6002721 4 likely to be constrained by the foundations of the wall. Accordingly, the AIA concludes that the proposal would not be expected to harm that tree, no tree protection measures would be required and no works would be necessary to the tree to facilitate the appeal scheme. I see no reason to conclude otherwise. 16. Therefore, the proposal is acceptable with respect to its impact on trees. Accordingly, it complies with Policy G7 of the London Plan Policy OS(f) of the Core Strategy. These generally seek to ensure that existing trees are retained wherever possible. Basement Impact 17. The Council maintains its concern in the absence of a site specific ground investigation report, flood risk report and structural method statement. I accept that on larger or more complex schemes, such information may be necessary prior to determination. However in this case, the increased depth of the proposed basement and the footprint of the excavation would be modest. Accordingly, a condition could reasonably be imposed to require further technical details to be submitted prior to excavation works taking place. Subject to imposition of such a condition, I consider that the proposal is capable of being acceptable with regard to its impacts on pollution and flood risk. No substantive evidence indicates otherwise. 18. The updated BIA includes detail on measures to minimise disruption to neighbours through control of noise, vibration and dust. Subject to a condition to secure these measures I am satisfied that the proposal would be acceptable with regard to its effect on the living conditions of neighbours. 19. Therefore, the proposed basement and lightwell would be acceptable with regard to impacts on pollution and flood risk and the living conditions of neighbouring occupants with particular regard to noise. Accordingly, it would comply with Policies D13 and D14 of the London Plan and Policy E(a) of the Core Strategy. Together these seek to ensure proposals avoid unacceptable impacts from matters such as noise, vibration and dust. Conditions 20. I have had regard to the conditions suggested by the Council and have amended these where necessary without changing their meaning. In addition to the standard time limit condition, it is necessary for a condition specifying the approved plans, in the interests of certainty. Detailed plans showing the proposed new windows, doors, brickwork, metal staircase and external surfacing are necessary in the interests of the character and appearance of the listed building. This includes a requirement for the replacement door to be of timber, removing the requirement for a separate condition. 21. A condition requiring submission of an updated basement impact assessment to include a Structural Method Statement signed and endorsed by a Chartered Civil Engineer or Chartered Structural Engineer is necessary to ensure the development maintains the structural stability of the host building and neighbouring properties and does not increase the risk of flooding elsewhere. Given the submitted construction management details it is not necessary for further details to be submitted by condition and a condition requiring compliance with those details has been imposed to ensure the development proceeds without unacceptable impacts on neighbours. Appeal Decision 6002721 5 Conclusion 22. For the reasons given, the appeal should be allowed. Rachel Hall INSPECTOR Schedule of Conditions 1) The development hereby permitted shall commence not later than three years from the date of this consent. 2) The development hereby permitted shall be carried out in accordance with drawing nos: 25 0110-3; 25 0110-8 C; and 25 0110-9 C. 3) Prior to the installation of new windows, doors, brickwork, metal staircase or lightwell surfacing hereby approved, full details of these shall be submitted to and approved in writing by the Local Planning Authority. These details shall include: • 1:10 elevations and 1:5 sections of all new windows (slimline (max 16mm) double glazing with true, integral glazing bars); • 1:10 elevations and 1:5 sections of the external door, to be constructed from timber, including materials, profiles and finishes; • Sample panel of proposed brickwork including mortar/pointing; • Sample of proposed new surface to the lightwell; • 1:10 section of the new metal staircase. • Details of handrails inclusive of materiality and profile. The development shall thereafter be carried out in accordance with the approved details. 4) Prior to the commencement of the basement works, and notwithstanding the submissions hereby approved, a revised Basement Impact Assessment including structural engineers’ drawings and specifications shall be submitted to and approved in writing by the Local Planning Authority. The Basement Impact Assessment shall include a Structural Method Statement signed and endorsed by a Chartered Civil Engineer or Chartered Structural Engineer with relevant conservation experience. This shall demonstrate by methodologies appropriate to the site, that the development maintains the structural stability of the host building and neighbouring properties and does not increase the risk of flooding elsewhere. Construction of the basement shall be carried out strictly in accordance with the Basement Impact Assessment approved under this condition and monitored by a suitably qualified professional throughout the construction process. 5) The development hereby approved shall be carried out in accordance with the construction management plan included at section 6 of the Seymour Building Services basement impact assessment (Ref SSR00593, dated 02/10/25).