Takero Shimazaki Architects has won the competition for a ‘contemporary skin’ to wrap around an office-to-residential conversion in Horsham, West Sussex
The London-based practice defeated Alma-nac, vPPR, TDO Architecture and Haptic Architects to win the exterior-only, invited contest for developer-builder Shuttleworth UK.
Takero Shimazaki’s winning proposal – intended to create a new ‘artefact of civic nature’ – will be harnessed for a £3 million conversion of the historic Prewetts Mill in the centre of the market town.
According to a statement by the winner: ‘Takero Shimazaki has sought to renew the existing concrete and brick structure with more formal window rhythms, proportions and order to create a new artefact of civic nature.
’Referencing Horsham’s character, the residential quality is brought to the former office structure by working with the existing strong horizontal slabs and bands, and adding a new vertical rhythm.’
The 1861 flour mill, which features a 1970s office extension, already has permitted development planning permission for conversion into 45 low-cost flats.
The developer is planning to submit a revised application to raise the roof by 1.5m and increase the number of planned apartments by 10.
The five emerging practices received £2,500 each to draw up concepts for the wrap, which will replace the old window pattern, enhance the new interior layout and highlight the former car park and entrance sequence of the building.
Submissions were judged on their quality, likelihood of winning planning, construction method, cost and value. The developer is planning to spend between £45,000 and £50,000 on each unit and £400,000-to-£500,000 on the external works.
Takero Shimazaki is expected to receive £25,000 to develop drawings for a planning application in early December.
Winner: Takero Shimazaki Architects
Prewetts Mill, Horsham
Takero Shimazaki Architect’s proposed design reimagines Prewetts Mill site and its existing structures for its new residential use through ‘formal correction’. t-sa have sought to renew the existing concrete and brick structure with more formal window rhythms, proportions and order to create a new artefact of civic nature.
Referencing Horsham’s character, the residential quality is brought to the former office structure by working with the existing strong horizontal slabs and bands, and adding a new vertical rhythm. Overlaying window proportions and applying details around larger windows, creating extra interest to the façade will highlight internal activities. The mansard roof, dormers, cladding and windows form a new language specific to the site’s context and heritage. Colourful tiles, the golden balconies and additional structures as well as the dark green roof bring subtle and yet tactile sensitivities relating this building to the past and the future.
Rounded timber shingles infill the office block, referencing intricate local tile detailing and timber cladding. Planting, street furniture and lighting buffer the site’s edges with the river and the street. Stone and cobbles upgrade the pedestrian areas and routes through the site.
The proposal refers the ‘modern’ era with the past, hence proposing a more enduring future heritage for Prewetts Mill site.
Finalist: Alma-Nac collaborative architecture
Prewetts Mill, Horsham
Our proposal has focussed on endeavouring to work with the existing structures of the mill building and the office space and unify the two together. Currently the language of the two buildings is distinctly at odds with one another with the vertical nature of the facade of the old mill building and the horizontal emphasis of the glazing and cladding of the office building. By adding relief to the brick we can create a facade that is richly textured and animated by the play of shadows during the course of a day. This use of brick extends down to ground level with the introduction of herringbone brick flooring within the entrance area, both externally and internally within the lobby. Fine detailing of the brick is employed on the walls to highlight openings around the lifts and provide a rich textural palette.
The River Arun that runs alongside the building is currently understated and the bank overgrown. By opening this up and once again revealing the river we hope that this can become a key feature of the site. We propose the creation of a ‘boardwalk’ to run alongside the embankment with notional jetty’s that serve to demarcate informal seating areas.
Finalist: Haptic architects
Prewetts Mill, Horsham
Our design approach to the conversion of the Prewetts Mill building draws simultaneously from its history, the current relationship to its newer office part and the wider context of Horsham. We shall reinforce the presence of the Mill as a single entity, restoring some of its façade and detail to provide a more monolithic quality. We propose to bring the Mill to the foreground, visually separating it from its extension, providing two distinct parts that reflect back to its former condition, whilst creating a contemporary and elegant juxtaposition. In doing so, we re-establish the importance of the Mill building in the context of Horsham and its relationship on a primary artery into the town.
We have taken a pragmatic approach to the conversion, doing more with less and respecting the architectural character and soul of the two buildings. Whilst the office building is of little architectural merit now, we believe that with simple, rational moves, we can create a building of residential character that is architecturally delightful. The office extension’s concrete banding is to be expressed, as is the dominant material palette of brick. The light-touch interventions are to insert full height windows and doors into this façade, along with smaller windows to bedrooms. The former ribbon windows will be replaced with new windows and textured brick infill panels, which can be formed with simple cavity wall construction. The replacement windows will maximise daylighting and views, particularly along the river frontage.
The brick infill will contrast with the Mill building, with lighter colour that references context buildings throughout Horsham. The existing brick is to receive a paint wash that is easy to maintain and will harmonize with the new brick infill. This contrast in brick tone and texture will reinforce the Mill as the original building whilst providing a more contemporary, residential character overall. The extension building will benefit from the addition of bolt-on balconies to add value and reinforce the residential character.
Finalist: TDO architecture
Prewetts Mill, Horsham
Our proposals for Prewetts Mill draw on the building’s context to give the structure a renewed identity as a contemporary, contextual, residential building. The forms and materials of historic buildings in the market town of Horsham, and the South East generally, combine to create a powerful rhythm of horizontal banding with vertical interruptions. Roofscapes are characterful and complex.
The building’s renewed form is achieved with the new roof. The multi-gabled roof structure introduces vertical interruptions to the existing horizontal banding of the building. The proposed materials draw on their context and are to clad the existing horizontal bands. At ground floor glazed pewter tiles reference mathematical tiles, while the existing brickwork is painted and glazed at first floor. The blackened timber roof battens at second floor and above reference black shiplapped timber, used widely at high level in buildings in Horsham and the South East.
Black as a primary colour introduces building tolerances in the detailing, while emphasising depth and layering. Gold as a secondary colour lifts the building. The composite effect gives the building a contemporary rhythm and identity, linked it to its context.
Finalist: vPPR architects
Prewetts Mill, Horsham
vPPR’s design for Prewett’s Mill celebrates its important history as a mill, and its current-day location as a gateway between the commercial centre and residential south of Horsham. The proposal restores the historic mill to its original state, and focuses on creating a strong public presence for the extension. Our design breaks down the excessive horizontality of the existing extension through the superimposition of a circular geometry, inspired by mill stones, to recall the history of milling across the façade. The circles are constructed with reflective glazed tiles, fixed to the existing brick surface, which bring depth and movement to the long elevations. The strong geometry of circles appears and disappears as one moves around the building due to the light reflections, resulting in a beautiful shimmering façade, that is almost like water. This design creates maximum impact through the smallest of interventions, sustainably minimizing demolition. The colour red, and the use of brick and tiles are highly contextual and recall the town’s vernacular architecture. Significantly these materials are also robust and low-maintenance so the building will look good over time. The proposal includes a new public realm area beside the river with wildflower planting and stepped seating, contributing to a distinctive new identity for Prewett’s Mill that is both bold and sensitive.