he Whitworth is one of Manchester’s historic cultural institutions. It is a creative laboratory for ideas about art as well as a visual research library for students and researchers from all over the world. It is this mix of intellectual inquiry and quirky spirit which will characterise the Whitworth’s next 10 years in its newly-expanded building.

The Whitworth is an amalgamation of a number of separate stages of development that have been undertaken over the past 126 years.

McInnes Usher McKnight Architects (MUMA) was selected in November 2009 through an architectural competition run by RIBA, held following the Whitworth’s award of a Stage 1 pass from the Heritage Lottery Fund in February 2009. The completed design remains true to that submitted under the competition and is a response to the client’s aspirations and clear and considered requirements, the site, and the inherent potential of the existing gallery.

MUMA’s design responds to the existing characteristics of the site and building. The new extension encapsulates the unresolved west end, creating a new frontage to the park. The architectural hierarchy and scale has been considered carefully to ensure that the clarity of the principal entrance off Oxford Road is not undermined.

Two new wings of contrasting character extend into the park containing a garden court and new entrance – a setting for art and events, which can bring new life to this part of the park. To the south, the transparent, slender wing of the café and its south-facing terrace celebrate the park context and the avenue of mature trees. To the north, the more solid form of the Landscape Gallery and Study Centre provide an urban edge and a visual context and acoustic buffer that contains the garden. The north wing also houses new and much needed back-of-house facilities including a new loading bay, art handling facilities and a substantial goods lift that can deliver art to the three main levels of the existing building.

New openings have been created in the existing building at significant locations connecting the new extension and providing the heart of the building with a range of long views – each connecting the green space beyond.

A promenade gallery wraps the existing exhibition galleries and provides a vantage point to view the garden and park. This glazed link maximises the visual connections to and from the park, and connects the central exhibition gallery to the garden. Thus, artworks inside can connect with artworks outside. The promenade also provides an environmental buffer, critical to the passive approach to environmental control, additional display space most suited for sculpture and a more informal environment within which visitors can relax.

In plan, the promenade is repeated at lower ground floor – a space of a very different character, which turns the former windowless basement into a generous lower ground floor. This lower promenade engages with the Art Garden and creates a welcoming informal park entrance at the west of the Whitworth.

Located as a destination on the main gallery level promenade, the Landscape Gallery to the north can provide a calm environment for the enjoyment of art. For a gallery often displaying landscape drawings and paintings, natural light and a visual connection with the park were fundamental. The gallery is rooflit and has a view addressing a single tree and the park beyond. To allow for flexibility there are light control mechanisms to both the rooflight and the window.

The solid elements of the north wing and lower ground floor are formed out of red brickwork (a bespoke ‘Whitworth Blend’ developed with brick manufacturer Northcot) – this is often articulated, sometimes with handmade faience elements. The brick bond patterns draw inspiration from the Whitworth’s textile collection. The brick articulation at entrances and particular openings creates shelter and casts shade – the depth of the reveals emphasising the mass of these elements. By way of counterpoint, the structure of the transparent café and promenade has been reduced to a series of slender polished stainless steel mullions – triangular in plan, they reflect the trees beyond, such that structure dissolves, visually, amongst the leafy reflections.

The glazed west elevation is protected from solar gain by the depth of the brickwork at lower ground level, incorporating sculpted Purbeck stone seating facing the garden and oak seating in the lower promenade. A dedicated stainless steel brise soleil veil shades the ground level promenade. Designed to cast shade whilst also maintaining views, the fine stainless steel fins are engineered so that they may flex in the wind.

Internally the materials are influenced by the Bickerdike interior – self finished materials; brick, Purbeck stone, timber (oak and ash) and terrazzo. Exposed concrete (with a high GGBS content) and lime plaster, provide thermal mass and a hygroscopic buffer in the collection zones.

Layering and patterning is considered throughout – from the rhythm of structural and architectural elements such as the promenade mullions and brise soleil, to the detail of the striated glass frit and slatted timber screens – as are the qualities of light and the interplay of shadow, reflection and transparency. Together these are intended to enrich and enliven the building whilst the restrained material palette serves to retain a sense of calm that is appropriate as a background to the building’s function.

Minismising environmental impact was a clear aspect of the brief and the project has responded to this in the logical distribution and use of spaces, (both in the existing building and new extension), the specification of sustainable materials and a passive approach to environmental servicing. By these means the target carbon consumption reduction of 10% will be achieved for the whole building (against the emissions of the existing building), despite the building size having increased by one third. The assessment carried out by the BREEAM consultant to date has confirmed that the ‘building is on track to be awarded BREEAM Excellent’.