McGarrigle Architects have been instructed by Manx National Heritage to prepare proposals for the refurbishment and conversion of the former Isle of Man Bank building, located at 1 Market Square, Castletown. The building is registered (R.B. No. 30) and sits within the Castletown conservation area.
The client’s brief consists of the following:
Conversion of the ground floor into an open-plan retail unit with lobby;
Conversion of the first floor into open-plan office space with reorganised staff welfare facilities, including a new staff kitchen, WCs, and a meeting room;
Removal of some internal walls on both floors to create larger open-plan layouts;
Replacement of the ground floor non-original timber windows and door with high-quality aluminium framed windows in a similar fenestration pattern, finished in a feature RAL colour, maintaining the sense of openness of the original open market arches;
Replacement of existing lay-in grid ceiling with plasterboard ceiling at ground floor with feature suspended lighting/service tracks.
Repair and refurbishment of the first-floor timber sash windows;
Repairs to existing external lime render
Renewal of the existing asphalt roof with a modern “Polyroof” liquid-applied warm-roofing system;
Replacement of existing lead parapet cappings with complimentary solid parapet cappings for improved weatherproofing;
Installation of a new roof access hatch to facilitate safe future maintenance;
New M&E throughout;
Provision of new interior finishes throughout;
New bespoke shop-fit joinery for the retail unit (details to be confirmed).
The proposals aim to preserve and enhance the historic character of this registered building while ensuring it has a sustainable new use that will support its long-term conservation.
2.0 Background
The client, Manx National Heritage, is the Isle of Man’s authority and a registered charity, responsible for protecting and promoting the Isle of Man natural and cultural heritage and are custodians of the majority of the island’s heritage sites. Other nearby sites in their custodianship in Castletown include Castle Rushen, the Old House of Keys, Old Grammar School, the Nautical Museum and the Castlegate Costa.
The building is on the Isle of Man’s Protected Building’s Registered (R.B. No. 30) by reason of its architectural and historic interest. The building occupies a prominent position within Castletown’s historic Market Square and is an important part of the town’s architectural heritage. Historically, the building has served as the former Custom House and Market Hall. While the façade shows a mix of architectural motifs and lacks cohesion in some respects, the building’s historic function and central location contribute significantly to its heritage value.
The building itself is a two-storey stone structure with a distinctive curved front elevation following the street line, deviating from an otherwise rectangular plan. Its architectural treatment is unusual, featuring semicircular arched openings at ground level with exposed stonework below the sills and brick arches without keystones, framed by roughcast and rendered detailing. The upper floor has more conventional rectangular windows, aligned above those below, and marked by string courses that introduce a strong horizontal emphasis. A battlemented parapet provides a stylised reference to the adjacent Castle Rushen.
Originally constructed as an open market with ground floor arches open to the square, the building was later enclosed and adapted as a bank. Over time, various non-original alterations have been made, including the insertion of modern windows within the ground floor arches and internal partitioning. Despite these changes, the building retains its prominent civic presence and historic significance as the former Custom House and Market Hall, contributing strongly to the heritage character of Market Square.
The conversion to retail and office space reflects a sustainable approach to adaptive reuse, allowing the building to remain active and occupied while protecting its historic character.
1. Planning History
Previous Planning Application (specific to the building itself) are listed below:
87/00446/B: Installation of wall cash dispenser, Barclay's Bank, Market Place, Castletown
89/00334/D: Erection of illuminated facsia sign and low energy floodlights, Barclays Bank, Market Square, Castletown. 92/00540/B: Repairs to parapets & details of leadwork, Barclays Bank, Market Square, Castletown.
98/02139/GB: Erection of CCTV dome, Barclays Bank Premises, Market Street, Castletown.
99/01206/GB: Installation of replacement cash machine, Barclays Bank, 1 Market Square, Castletown.
02/01222/GB: Erection of advertising signs
06/01610/CON: Registered Building Consent for the installation of a security camera on front elevation (In association with 06/01609 GB)
06/01609/GB: Installation of a security camera on front elevation (In association with 06/01610CON)
10/01712/GB: Installation of an air conditioning condenser unit on side elevation (In association with 10/01713 CON)
10/01713/CON: Registered Building Consent for the installation of an air conditioning condenser unit on side elevation, RB no 30 (In association with 10/01712 GB)
11/01020/CON: Registered Building Consent for installation of an air conditioning condenser to rear elevation (Registered Building no 30 in association with 11/01019/GB)
11/01019/GB: Installation of an air conditioning condenser to rear elevation (in association with 11/01020/CON)
15/01209/CON: Registered Building Consent for the installation of external lighting (RB no 30 in association with 15/01208/GB)
15/01208/GB: Installation of exterior illumination (in association with 15/01209/CON, 15/01210/CON & 15/012011/CON)
16/00011/GB: Replacement of existing asbestos roof tiles on pitched roof over escape stairs with natural slate (in association with 16/00012/CON)
16/00012/CON: Registered Building Consent for replacement of existing asbestos roof tiles on pitched roof over escape stairs with natural slate (RB no 30 in association with 16/00011/GB)
2. Site & Access
The property is located in the north-west of Market Square, Castletown and forms part of the historic core of Castletown. It is bounded by neighbouring heritage properties, most notably Castle Rushen to the rear. Market Square is a long linear Square that leads onto the main shopping street of Arbory St. and the adjacent Malew St. The building itself is a key contributor to the setting of the square.
Vehicular access is limited due to its town location and the part pedestrianisation of Market Square. pedestrian access is provided directly from Market Square, suitable for both the proposed retail unit and first-floor offices. The site is well served by public transportation, with a bus stop at the opposite end of the square.
3. Design Proposals
The building footprint remains unchanged as part of this proposal, and external works are limited to window replacement, roof covering renewal, and parapet capping improvements (please refer to Schedule for full details).
Ground Floor – Retail Conversion
Removal of non-original internal partitions to create an open-plan retail space.
Replacement of modern windows in the original market arches with new aluminium windows in a feature RAL colour, providing improved visual quality and reinstating the historic rhythm of the façade.
Installation of new services to suit shop layout
New internal shop-fit joinery (details to follow in coordination with the tenant and Manx National Heritage).
First Floor – Office Conversion
Removal of non-original partitions to form a more open and flexible office layout.
Provision of a new staff kitchen, upgraded WCs, and a new meeting room.
Installation of new services to suit office layout
Retention and repair of existing historic timber sash windows.
Roof & External Fabric
Repairs to external fabric as required.
Replacement of the existing roof covering with a new Polyroof system, offering improved durability and weather protection.
Replacement of lead parapet cappings with solid cappings to resolve ongoing maintenance issues.
Introduction of a new, discreet roof access hatch to allow safe future maintenance without impacting the building’s appearance.
Internal Finishes New finishes throughout both floors to provide high-quality, functional retail and office environments.
6.0 QUANTITY The proposals do not alter the existing footprint, massing, or overall volume of the building. Internal works are limited to the removal of modern partitions and installation of updated finishes.
7.0 MATERIALS & FINISHES
Ground Floor Windows: Aluminium framed windows in a feature RAL colour, designed to complement the historic arches and reinstate the building’s original open-market appearance.
First Floor Windows: Existing timber sash windows repaired and redecorated in heritage-appropriate finishes.
Roof: New Polyroof liquid-applied system laid to falls with improved waterproofing, accompanied by solid parapet cappings for enhanced longevity.
Internal Joinery: Bespoke shop-fit joinery for the retail unit and high-quality office fit-out upstairs, designed for minimal impact on historic fabric.
8.0 SUSTAINABILITY The scheme enhances the building’s sustainability by:
Reusing and adapting the existing structure rather than replacing it;
Repairing and upgrading original timber windows to improve energy performance while preserving historic material;
Installing durable warm-roofing and parapet solutions to reduce maintenance and extend the building’s life;
Providing long-term viable uses (retail and office), ensuring ongoing maintenance and occupation of this important heritage asset.
9.0 HERITAGE IMPACT & JUSTIFICATION The proposed works have been developed with careful consideration of the building’s registered status, its historic role as the former Custom House and Market Hall, and its prominent position within Market Square, Castletown.
Preservation of Historic Fabric:
The first-floor timber sash windows (albeit non-original), which form part of the building’s historic fabric, will be repaired and retained in situ, preserving original material wherever possible.
The overall external form, including the distinctive curved façade, string courses, and battlemented parapet, will remain unchanged, maintaining the building’s civic presence.
Enhancement of Architectural Character:
The existing non-original single-pane timber windows at ground floor, will be replaced with highquality, double-glazed aluminium windows in a feature RAL colour will clearly express the windows as being non-original to the original open arches. These will better respect the original open market design and visually enhance the façade, drawing in visitors to the retail unit.
Removal of non-original internal partitions on both floors will reinstate larger, more open internal spaces, closer to the building’s historic layout.
Sensitive Modernisation:
The roof will be replaced with a new Polyroof system and solid parapet cappings to resolve longstanding water ingress issues without altering the building’s profile or appearance.
A discreet roof access hatch will be introduced solely to facilitate safe future inspection and maintenance, ensuring minimal visual impact.
Sustainable Reuse:
Converting the ground floor to retail use and the upper floor to offices secures a viable long-term use for the building, ensuring its ongoing occupation, maintenance, and protection from deterioration.
New internal finishes and welfare facilities will provide functionality for modern use while avoiding harm to historic fabric.
Overall, the proposals preserve and enhance the building’s heritage significance, reinstating aspects of its historic character while introducing carefully considered, reversible interventions. This approach ensures that the former Isle of Man Bank building remains an active and well-maintained landmark within Market Square, contributing positively to the setting of adjacent heritage assets, including Castle Rushen.
10.0 CONCLUSION The proposed refurbishment and conversion of the former Isle of Man Bank building represents a sensitive, heritage-led approach to securing the future of this registered building.
The works preserve key historic features, remove unsympathetic alterations, and introduce high-quality, reversible interventions to create functional modern spaces for retail and office use.
We respectfully request that planning approval and registered building consent be approved in support this application and grant the necessary consents.
Appendix A: Site Photographs
1.0 Exterior – South-West Elevation
2.0 Exterior - South-East Elevation
A photograph of a white, two-story historic building with arched ground-floor windows situated on a paved town square.A photograph of a distinctive white two-story building with crenellated parapets and arched ground-floor windows, situated in a paved town square with a ping pong table in the foreground.
3.0 Exterior – North-East Elevation
4.0 Exterior - Parapet
A low-angle exterior photograph of a large, historic stone building featuring a crenellated parapet and arched windows. The image shows the side elevation of the registered building alongside a lower stone wall and green gates.A close-up photograph showing the upper parapet and roofline of a cream-colored building with visible weathering stains and stone coping details.
5.0 Interior – Ground Floor - 1
6.0 Interior – Ground Floor - 2
Interior photograph of a commercial building hallway featuring a staircase, power-assisted door, and fire safety equipment.Interior photograph of an empty commercial room featuring arched windows, drop ceiling, and carpeted flooring.
7.0 Interior – Ground Floor - 3
8.0 Interior – Ground Floor - 4
Interior photograph of a commercial property with arched windows and a 'for sale' sign.Interior photograph of a commercial or office space featuring arched windows, a glass entrance door, and carpeted flooring.
9.0 Interior – Ground Floor - 6
10.0 Interior – Ground Floor - 6
Interior photograph of an empty commercial room featuring arched windows and carpeted flooring.Interior photograph of an empty commercial room featuring arched windows, a drop ceiling, and a 'To Let' sign.
11.0 Interior – First Floor - 1
12.0 Interior – First Floor - 2
Interior photograph of a room featuring two large sash windows and wooden floorboards, likely part of a listed building renovation.Interior photograph of a room featuring traditional sash windows and wooden floorboards, likely part of a historic property undergoing renovation.
13.0 Interior – First Floor - 3
14.0 Interior – First Floor - 4
Interior photograph of an empty room featuring white walls, wooden flooring, and suspended fluorescent lights.Interior photograph of a room with white walls, a large ceiling beam, and an open doorway featuring a transom window.
Appendix B: Archive Photos Anddrawings
15.0 MNH Archive – Market Square (No. 1 in background)
16.0 MNH Archive - Market Square (No. 1 to left)
A black and white photograph taken from inside a building looking out through open doors onto a town street featuring a central column monument and parked cars.A sepia-toned historical photograph showing a tall fluted column monument standing next to a crenellated stone building.A vintage sepia-toned photograph showing a stone war memorial or monument in a town square with historic stone buildings and castle walls in the background.
17.0 MNH Archive – (No. 1 to left)
18.0 MNH Archive – (No. 1 in background)
END OF DOCUMENT
A vintage black and white photograph showing a town square with a tall column monument and a historic stone building with crenellations in the background.A vintage sepia-toned photograph depicting a street scene with terraced buildings on the left and a tall column monument in the center.A vintage sepia-toned photograph depicting a town square with a central monument and surrounding historic buildings.
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Source & Provenance
Official reference
25/00794/CON
Source authority
Isle of Man Government Planning & Building Control
