Inspiration

Moss House

Glenn Howells shows the versatility of a repeating structural grid, with a building designed to adapt to University College Birmingham’s ever-changing needs

As a relatively new institution in a competitive marketplace, University College Birmingham (UCB) asks a lot from its flagship buildings. They need the sharp looks to lure in prospective students, while also conveying the gravitas of an established university that plans to be around for a long time. 

But above all, they need spaces that can adapt to a curriculum that changes as fast as the 21st-century work environment. UCB mainly teaches vocational subjects, so its facilities range from training restaurants to flight simulators to financial trading suites. “Every summer they knock their existing buildings about to suit new courses,” says Simon Pearson, a director at Glenn Howells Architects. “Even during this project, we inherited a completely new medical services course.”

The project Pearson is referring to is Moss House, a three-storey teaching and sports facility in central Birmingham’s historic Jewellery Quarter. It houses a range of functions: teaching spaces, lecture theatres, a diner, a sports laboratory, even a running track. But with an intended lifespan of more than 100 years, it will inevitably see uses that the university hasn’t even begun to plan for.

The building is based around a simple repeating grid of in-situ concrete elements. Columns are placed at 7.5m intervals in both directions, with 300mm-deep floor slabs at 4m floor-to-floor heights. “I wanted to set up a grid that I could just play with in terms of the positioning of the functional spaces,” says Pearson. Everything aligns with the grid – even the 100-seat lecture theatres, notoriously inflexible due to their extra height and complex servicing needs, slot into a single storey.

Concrete’s robustness and acoustic performance lent itself to such an approach, Pearson adds, as it meant that most spaces can be put to a variety of social or study uses. “There’s no need for downstand beams or additional thickening of the slab, so we had complete flexibility as to where penetrations and services could go,” he says. “And it let us create stacked spaces with sensitive acoustic separation requirements without having to do any extra work. We knew the 300mm-deep concrete slabs were going to work acoustically whatever their use.”

This is best illustrated by the high-intensity fitness lab, gym and running track, located on the top floor of the building. Such a facility would normally be sealed off on a ground floor (“If you’ve got athletes picking up 200kg weights, you don’t want them being dropped on top of teaching spaces below,” points out Pearson), but the university was keen for the entrance to house more outward-facing spaces such as a cafĂ© and shop. “It forced us to put sports facilities at a higher level. You wouldn’t be able to do that in anything other than concrete.” He adds that the top-floor sports centre adds to the university’s sales pitch: “It’s a unique attribute and a fantastic draw for prospective students.”

The services, like the structural grid, are deceptively simple. Two rafts run neatly from a core on the east side of the building along either side of the atrium, branching off into a small ventilation bulkhead at the front of each room. The mixed-mode ventilation system includes openable louvres on both sides of the windows, with stale air extracted via the atrium. This reduced the need for ductwork by half, allowing more of the concrete soffits to remain exposed – an important part of the ventilation strategy, as it maximises the temperature-stabilising effects of the soffits’ thermal mass.

Because so much of the concrete in Moss House is exposed, the architects and concrete contractor spent about three months testing the specification with different suppliers and different formwork. Pearson’s team also designed all of the concrete joints and junctions, prototyping each of the connections with the contractor’s joiners.  

The chosen mix was a 55% GGBS concrete, light in tone, cast against a laminate-faced board. This left a smooth as-struck surface that required minimal improvements. The client’s clerk of works closely supervised all aspects of the concrete pour, Pearson adds, which was essential to getting a high-level repeatable finish. “He ensured it was rigorous, even down to making sure the same person used the poker to compact the concrete as the previous day.” Such exactitude was particularly important when it came to the 6m-high columns in the atrium, which were cast without intermediate joints – a process that involved sourcing 6m-high formwork boards from Germany.

Externally, Moss House is quite restrained for a high-profile university building. Even though the client wanted a “shouty” design to grab the attention of its teenage customer base, the architects successfully argued in favour of prioritising the historic context. “We spent a huge amount of time getting into the grain of the surrounding industrial buildings,” says Pearson. “A number of themes emerged that we used to develop the architecture of our building: the way the elevations are proportioned, fenestration patterns, the consistent rhythm of facade and structure.” 

The resulting facade is composed of English Bond bricks, terracotta sills and lintels and aluminium louvres, all fixed to 150mm-deep insulated precast-concrete panels – “precasting gave us the ability to control the quality of the installation to a very high degree,” says Pearson. The design team was able to stretch the budget to a high-quality brick – chosen to match the tones of a nearby 19th-century building – by specifying a slightly more expensive double-faced variety that could be cut in half and effectively used twice. This solution is also more robust and less prone to chipping than thinner, conventional brick slips.

But does it work as a sales pitch to prospective students? “We decided to invert the idea of a dramatic university building,” explains Pearson. “So instead of having a big, blingy box, the interior would create that drama.” The concrete grid may be repetitive in plan, but it conjures up some compelling vertical spaces. The atrium has been carved out of the centre of the structure, rising up the full three-storey height of the building. A staggered oak staircase, inhabited bridges and terraces all add to the sense of theatre.

These open spaces can also adapt to the unexpected, as Moss House’s eventful first year has shown. “This building lent itself from day one to being used in the pandemic,” says Pearson. “The way the frame has composed the spaces, they could have one-way traffic, with generous circulation zones around the building. The university has had to close other buildings, but this one has been able to operate under those extreme pressures.” It all bodes well for the next 100 years – however the curriculum changes.

PROJECT TEAM

Architect Glenn Howells Architects
Structural engineer Couch Consulting Engineers
Contractor Kier
Precast concrete facade FP McCann
Concrete frame Thames Formwork

Photos Rob Parrish