Officer Report

Application No.: 25/90842/B Applicant: Mr & Mrs William Mark & Karen Ann Cowley Proposal: Erection of extension to side elevation and alterations to doors and fenestration of existing dwelling house, erection of replacement garden shed with log store (part retrospective) Site Address: Rosecroft 3 Sunnybank Avenue Onchan Isle Of Man IM3 3BN Planning Officer: Paul Visigah Photo Taken: 12.11.2025 Site Visit: 12.11.2025 Expected Decision Level: Officer Delegation Recommended Decision: Permitted Date of Recommendation: 12.12.2025 _________________________________________________________________

Conditions and Notes for Approval

C : Conditions for approval N : Notes attached to conditions

• C 1. The development hereby approved shall be begun before the expiration of four years from the date of this decision notice.

Reason: To comply with Article 26 of the Town and Country Planning (Development Procedure) Order 2019 and to avoid the accumulation of unimplemented planning approvals.

• C 2. Prior to the commencement of the development hereby approved, full details of all proposed external materials and finishes (including render, fibre cement panels, roofing membrane, and fenestration) shall be submitted to and approved in writing by the Department. The development shall thereafter be carried out in accordance with the approved details and retained as such.

Reason: To ensure visual coherence and safeguard the character of the dwelling and locality in accordance with Strategic Policy 5 and Environment Policy 42.

This application has been recommended for approval for the following reason.

The proposal accords with the Isle of Man Strategic Plan 2016 and the Area Plan for the East by delivering a proportionate extension within an established residential curtilage, consistent with Paragraph 8.12.1. The design respects the architectural integrity of the existing dwelling, maintains the verdant and low-profile character of Sunnybank Avenue, and avoids visual intrusion, satisfying Strategic Policies 3 and 5 and Environment Policy 42. While the separation distances (16.2 m and 18.8 m) fall below the 20 m guideline in the Residential Design Guide, the single-storey form, boundary screening, and restrained massing mitigate any potential impact on privacy and outlook, ensuring compliance with General Policy 2(g). Access and parking remain unchanged and meet Transport Policy 7 standards. No objections have been

received, and the scheme represents efficient use of land without compromising character or amenity.

Plans/Drawings/Information; This approval relates to the following plans and documents received 04 September 2025:

• o Location Plan
• o 1 - Existing Site Plan, Plans and Elevations
• o 2 - Proposed Site Plan, Plans, Elevations and Section
• o 3 - Shed Plans and Elevations
• o Drawing Register _________________________________________________________________

Right to Appeal

It is recommended that the following organisations should NOT be given the Right to Appeal: o Onchan District Commissioners - no objections

_________________________________________________________________ Officer’s Report

1.0 APPLICATION SITE - 1.1 The site is the residential curtilage of Rosecroft, 3 Sunnybank Avenue, which is a singlestorey detached property, situated on the northern side of Sunnybank Avenue which ends in two cul-de-sacs, one on the western end, and another on the southern end. - 1.2 The application property which sits along the eastern cul-de-sac sits on an elevated site level relative to the adjoining highway, with the dwelling positioned over 1.2 m above the road level. The site is largely enclosed in mature hedging which wraps around the property, with views to the property only achievable along the site frontage, as the frontage hedging sits about 2 m. The property is visible due to the elevated site level, and only glimpses of the roof can be seen from the west, north and eastern boundaries due to the increased level of the hedges, together with trees on these boundaries. - 1.3 The application property is a 1970s-1980s single-storey detached bungalow of masonry construction, finished in painted render under a shallow pitched roof clad in brown concrete tiles. The front elevation faces south and includes a recessed entrance porch, while an integral single garage occupies the western side. White uPVC windows and rainwater goods complement the simple design. The dwelling sits on an elevated plot approximately 1.2 m above road level, with a concrete driveway providing access and off-street parking. The frontage is enclosed by a mature hedge around 2 m high, and the garden is landscaped with lawn and shrubs. Ancillary timber sheds are located along the western boundary. - 1.4 The site lies within a well-established residential cul-de-sac predominantly comprising 1970s bungalows with a small number of two-storey dwellings. Properties are arranged on generous plots with landscaped gardens and share a consistent low-rise form with shallow pitched roofs and simple rendered finishes, creating a uniform suburban character. The street scene is verdant and well-maintained, defined by mature hedging, ornamental shrubs, and occasional trees that provide strong enclosure and privacy.

2.0 THE PROPOSAL - 2.1 Planning approval is sought for erection of extension to side elevation and alterations to doors and fenestration of existing dwelling house, erection of replacement garden shed with log store (part retrospective).

2.2 The proposed works would include:

• a. Erection of a flat roofed extension to the eastern elevation of the dwelling to serve a new family room, a utility, dressing room and ensuite to serve the bedroom on this elevation. The extension would project 10.2 m from the north elevation of the existing snug on the east side of the dwelling and would be 3.4 m wide. This extension would be about 3.2 m tall from the ground level to the top of its flat roof, 2.9 m to the eaves, and 3.8 m to the top of the hip roofed lantern over the flat roof. A new UPVC patio/French doors would provide access from the new family room to the garden.
• b. Removal of existing bay window with roof over on the south (front elevation) of dwelling and installing a new window within the opening.
• c. Remove existing external steps up to front door and renew concrete steps with a handrail on both sides.
• d. Remove existing window situated on the rear elevation of dwelling by lobby to garage, extend aperture and install a new door and window.
• e. Remove facing brickwork on the external elevations of dwelling and replace with painted render, together with panels of dark coloured fibre cement boarding.
• f. Replace existing door with new composite front door with glazed panels either side.
• g. Extending the existing patio area to wrap around the new side extension.

2.3 All new windows and doors are to be UPVC double glazed units. The flat roof is to be finished in Decathane or similar liquid single ply plastic roofing membrane in dark colour. - 2.4 Other works include the erection of a replacement garden shed with integrated log store, measuring approximately 3.5 m in width, 5.2 m in length, and 2.7 m in height to the roof ridge. The structure would be finished in timber boarding with timber-framed double doors and windows, and a dark grey profiled metal roof incorporating clear panels. This element of the works is retrospective. - 2.5 No trees or mature hedging would be removed to facilitate the development. There would be no changes to the access and parking arrangement for the site.

- 3.0 PLANNING POLICY

3.1 Site Specific:

• 3.1.1 The application site is within an area recognised as being within predominantly residential use under the Area Plan for the East (Map 6 - Onchan). The site is not within a Conservation Area or Registered Tree Area, and there are no registered trees on site. The site is also not prone to flood risks.

3.2 National: STRATEGIC PLAN (2016)

• 3.2.1 Due to the zoning of the site and the proposed works, the following sections of the Isle of Man Strategic Plan 2016 are relevant:

• 1. General Policy 2 - 'Development Control' considerations.
• 2. Paragraph 8.12.1 - General presumption in favour of extensions to existing properties (excluding Conservation Areas or Registered Buildings).
• 3. Strategic Policy 1 - Efficient use of land and resources
• 4. Strategic Policy 2 - Development focussed in existing towns and villages
• 5. Strategic Policy 3 - Development to safeguard character of existing towns and villages.
• 6. Strategic Policy 5 - Design and visual impact.
• 7. Environment Policy 42 - character and need to adhere to local distinctiveness.
• 8. Transport Policy 7 - Parking Provisions
• 9. Community Policy 10 - Proper access for firefighting appliances
• 10. Community Policy 11 - Prevention for the outbreak and spread of fire

- 4.0 OTHER MATERIAL CONSIDERATIONS

4.1 Residential Design Guide (2021)

• 4.1.1 This document provides advice on the design of new houses and extensions to existing property as well as how to assess the impact of such development on the living conditions of those in adjacent residential properties and sustainable methods of construction.
• 5.0 PLANNING HISTORY

5.1 The site was the subject of a planning application for Erection of conservatory under PA 95/01129/B which was refused by the Planning Committee on 01.12.1995. - 5.2 There has been a number of approvals granted within the immediate street scene for extensions and alterations to the neighbouring properties.

6.0 REPRESENTATIONS Copies of representations received can be viewed on the government's website. This report contains summaries only. - 6.1 Onchan District Commissioners have recommended that the application be approved for planning purposes only (29 September 2025).

6.2 No comment have been received from neighbouring properties. - 7.0 ASSESSMENT

7.1 The fundamental issues to consider in the assessment of the application include:

• 1. Whether the proposed extension and alterations are acceptable in principle within a predominantly residential area (General Policy 2; Strategic Policy 1; Strategic Policy 2; Paragraph 8.12.1);
• 2. Impact of the extension, fenestration changes, and external finishes on the character of the dwelling (Strategic Policy 3; Strategic Policy 5; Environment Policy 42; Residential Design Guide);
• 3. Whether the proposal respects the established suburban character and maintains visual harmony with surrounding properties (Strategic Policy 5; Environment Policy 42);
• 4. The Potential effects on neighbouring properties in terms of outlook, privacy, and overshadowing (General Policy 2(b, c); Residential Design Guide); and
• 5. Access and Parking Issues (Transport Policy 7; General Policy 2(g))

7.2 Principle of Development

• 7.2.1 The application site lies within a predominantly residential area as designated in the Area Plan for the East, where extensions to existing dwellings are generally supported under Paragraph 8.12.1 of the Strategic Plan. This presumption is conditional upon proposals not having an adverse impact on adjacent properties or the surrounding area. In this case, the proposed extension and alterations remain within the established curtilage and do not introduce a new dwelling or intensify use beyond what is typical for the locality.
• 7.2.2 Strategic Policy 1(a) and (b) emphasise efficient use of land and resources, including optimising previously developed land and maintaining amenity standards. The proposal achieves this by extending the existing footprint rather than creating additional units within the site and by retaining landscaped garden space around the dwelling. The extension occupies only a small portion of the green space that contributes to the visual amenity of the area, thereby satisfying Environment Policy 42.
• 7.2.3 The site benefits from existing infrastructure and services, consistent with Strategic Policy 1(c) and Strategic Policy 2, which seek to focus development within established settlements.
• 7.2.4 On this basis, the principle of development is acceptable. However, compliance with policy is contingent upon the detailed design respecting the character of the locality and safeguarding residential amenity, which are considered in subsequent sections.

7.3 Impact on Character and Appearance of existing dwelling

• 7.3.1 General Policy 2(b) requires development to respect the site and its immediate context in terms of siting, layout, scale, form, and design. The existing dwelling is a single-storey bungalow with a shallow pitched roof and a prominent flat-roofed section. The proposed extension builds upon this established form by enlarging the flat-roofed element rather than introducing a new feature. Its maximum height of 3.8 m (including the hipped roof lantern) remains below the main ridge, ensuring subordination and avoiding dominance within the site.
• 7.3.2 The external finishes, which include painted render with panels of dark fibre cement boarding, reflect the prevailing rendered character of the property while introducing a contemporary accent. Fenestration changes, including new patio doors and replacement windows, are proportionate and maintain the rhythm of openings. These measures comply with Strategic Policy 5 and the Residential Design Guide, which advocate coherent design and contextual response.
• 7.3.3 The replacement shed, although larger than the existing structure, is positioned along the western boundary within the garden area and finished in timber boarding with a profiled metal roof. Its scale and materials are appropriate for an ancillary building and maintain functional coherence within the curtilage. Screening by mature hedging further limits its visual presence within the site.
• 7.3.4 Overall, the proposal respects the architectural integrity of the dwelling and responds positively to the site context, meeting Strategic Policy 3(b) and Environment Policy 42 by avoiding incongruous additions and reinforcing the established character of the site.

7.4 Impact on Character of Locality and Local Distinctiveness

• 7.4.1 In assessing the potential impacts of the development on the character of the locality and immediate street scene, it is considered that the cul-de-sac is defined by a consistent pattern of single-storey dwellings with shallow pitched roofs, generous plots, and strong enclosure provided by mature hedging. This creates a coherent suburban character defined by mature landscaping and a low-profile built form.
• 7.4.2 The proposed extension, while enlarging the flat-roofed section of the property, would not disrupt this pattern. Public views are largely confined to the site frontage, where the extension would appear as a discreet addition behind established boundary planting. Its scale and horizontal emphasis remain compatible with the prevailing form, and the retention of hedging ensures the visual continuity of the street scene.
• 7.4.3 The replacement shed is positioned within the garden and screened from neighbouring plots, avoiding any perception of visual clutter. Its materials and muted colour palette are typical of ancillary structures in residential settings and do not introduce discordant elements.
• 7.4.4 Based on the foregoing, it is judged that the development maintains the rhythm and openness of Sunnybank Avenue, safeguarding the established suburban character and complying with General Policy 2(c), Strategic Policy 3, and Environment Policy 42.
• 7.5 Impact on Residential Amenity

• 7.5.1 A key consideration in this assessment is whether the proposal would materially alter the living conditions of neighbouring occupiers. General Policy 2(g) and the Residential Design Guide require development to avoid unacceptable impacts on outlook, privacy, and overshadowing. The extension is single-storey and positioned on the eastern side of the dwelling, with separation distances of approximately 18.8 m to No. 1 Sunnybank Avenue (to the east) and 16.2 m to No. 9 Highfield Crescent (to the north). This orientation, combined with the generous plot size and established boundary planting, ensures that these distances

• remain well within acceptable parameters, preventing any material harm to neighbouring amenity.
• 7.5.2 Beyond separation, the extension's design further mitigates potential impacts. It sits within the established garden envelope and does not break the building line, preserving the spatial rhythm of the plot. The flat roof profile and restrained height reduce perceived bulk, ensuring the addition does not appear overbearing when viewed from adjoining properties. The new fenestrations are also at positions that do not introduce actual or perceived overlooking. These qualitative factors complement the physical separation in maintaining neighbourliness and satisfy the design principles set out in the Residential Design Guide.
• 7.5.3 The replacement shed, at 2.7 m to ridge, is modest in height and located along a boundary where ancillary structures are typical. No windows are proposed that would create overlooking concerns, and the existing vegetation mitigates any visual intrusion. Its intended use as a garden store and log store is consistent with domestic activity and does not introduce noise or disturbance beyond what is normal for the locality.
• 7.5.4 The absence of neighbour objections reinforces the conclusion drawn from the physical and design factors assessed above. When considered against the Residential Design Guide and General Policy 2(b, c, g), the proposal demonstrates compliance with principles of privacy, outlook, and good neighbourliness. On this basis, the development is judged to have no adverse effect on residential amenity.

7.6 Access and Parking

• 7.6.1 The proposal does not alter the existing vehicular access or driveway arrangement. In addition, the site continues to benefit from a wide frontage and a level hardstanding that accommodates off-street parking without compromising manoeuvrability. Importantly, the extended footprint is contained within the garden envelope and does not encroach on areas used for vehicle turning or parking.
• 7.6.2 Turning to policy compliance, Transport Policy 7 requires parking provision to meet current standards, typically two spaces per dwelling, with at least one located within the curtilage and behind the front elevation. In this case, the existing arrangement satisfies this requirement, and no changes are proposed that would reduce compliance. The integral garage remains available for use, and the driveway provides additional capacity.
• 7.6.3 Consequently, the development meets the requirements of Transport Policy 7 and General Policy 2(h), ensuring safe and convenient access and adequate parking provision without introducing any highway safety concerns.

- 8.0 CONCLUSION

8.1 The proposal represents a proportionate extension within an established residential curtilage and has been assessed against the Isle of Man Strategic Plan 2016, the Area Plan for the East, and the Residential Design Guide. The design respects the architectural integrity of the existing dwelling, maintains the verdant and low-profile character of Sunnybank Avenue, and avoids visual intrusion. Although the separation distances (16.2 m and 18.8 m) fall below the 20 m guideline in the Residential Design Guide, the single-storey form, boundary screening, and restrained massing mitigate potential impacts on privacy and outlook, ensuring compliance with General Policy 2(g). Access and parking remain unchanged and meet Transport Policy 7 standards. No objections have been received, and the scheme accords with Strategic Policies 1, 2, 3, and 5, General Policy 2, and Environment Policy 42. Accordingly, the proposal is considered acceptable and is recommended for approval, subject to conditions. - 9.0 RIGHT TO APPEAL AND RIGHT TO GIVE EVIDENCE

9.1 The Town and Country Planning (Development Procedure) Order 2019 sets out the process for determining planning applications (including appeals). It sets out a Right to Appeal

(i.e. to submit an appeal against a planning decision) and a Right to Give Evidence at Appeals (i.e. to participate in an appeal if one is submitted).

9.2 Article A10 sets out that the right to appeal is available to:

• o applicant (in all cases);
• o a Local Authority; Government Department; Manx Utilities; and Manx National Heritage that submit a relevant objection; and
• o any other person who has made an objection that meets specified criteria.

9.3 Article 8(2)(a) requires that in determining an application, the Department must decide who has a right to appeal, in accordance with the criteria set out in article A10. - 9.4 The Order automatically affords the Right to Give Evidence to the following (no determination is required):

• o any appellant or potential appellant (which includes the applicant);
• o the Department of Environment, Food and Agriculture, the Department of Infrastructure and the local authority for the area;
• o any other person who has submitted written representations (this can include other Government Departments and Local Authorities); and
• o in the case of a petition, a single representative. _____________________________________________________________________________________________________

I can confirm that this decision has been made by a Principal Planner in accordance with the authority afforded to that Officer by the appropriate DEFA Delegation and that in making this decision the Officer has agreed the recommendation in relation to who should be afforded interested person status and/or rights to appeal.

Decision Made : Permitted Date: 19.12.2025 Determining Officer Signed : J SINGLETON Jason Singleton Principal Planner

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