There's nothing dry or academic about Rick Mather's university buildings: full of the sense of the outdoors - rooftop gardens, terraces and courtyards - they are the essence of his humane modernism.

By Eleanor Young

As Liverpool's year as capital of culture draws to a close, so will Rick Mather's regular visits to the city. His Art and Design Academy for Liverpool John Moores University will open to students in January. It is the latest in a line of distinguished university buildings from a practice that has never had more than 40 architects working for it.

Academic projects are woven into the history of Rick Mather Architects. Mather's first public project was the Architectural Association, which he was asked to replan in 1978. The bar - a subtly powerful composition of marble and mirrors - remains comfortably ensconced in the AA's first floor 30 years on. At the University of East Anglia, the recommendation of one Norman Foster secured him, from the late 80s, a series of student halls and academic schools alongside Denys Lasdun's ziggurat blocks. In the mid-90s he struck gold with a string of arts projects: the Dulwich Picture Gallery, the Wallace Collection and the National Maritime Museum (with BDP).

There has also been university work in Leicester, Lincoln, London, Oxford, Reading, Southampton and now Liverpool. In Oxford, Mather is working for three colleges, with projects including an entirely new quad for Keble College, and this has fed into work on the huge Ashmolean Museum extension.

Seated in his office on Camden High Street in north London, Mather is sipping hot Barley Cup. He seems nervously self-conscious, repeatedly glancing at my notebook as if to check what I am taking down. Normally his manner is easygoing, any directness softened by a mellow American accent. The thick white cotton shirt, tucked neatly into black jeans, is as precise and unshowy as his work. And eventually the smile always glinting behind his eyes breaks out and he explains he is just trying to see how I am managing to write while barely looking at the page.

Figuring things out is something Mather likes to do. Clients often appreciate the fact he has anticipated the need for a bar (the AA) or an additional new building (Keble College). Much of the practice's university work has been won in competition and his ability to fit more into a site than seemed possible is probably as strong a reason for his success as his other more subtle design skills.

Certain tropes emerge - particularly that of building on the perimeter while creating rather special slices of landscape in between buildings. At Keble College, while other shortlisted architects were stressing that only one building would fit into the centre of the old Fellows' Garden, Mather impressed the college with the possibilities of building to the edge of the site, creating space for future expansions (which he later built) and a modern quad to complement that within the William Butterfield buildings next door.

And when the ARCO building (93 study bedrooms plus conference facilities) had gone through planning and the college decided it needed to add more to the programme, Mather set about 'converting' the envelope, digging deep into the garden site with a skilful use of levels both inside and out. His winning competition entry for the college's latest acquisition, the Acland Hospital site, gave them 'more than they could dream of' (in Mather's words).

The inability of universities to look ahead and plan the way they will develop perplexes Mather, although he puts it more politely. 'We encourage people wherever possible to do a masterplan,' he says. Though known for his buildings, he has a strong interest in planning; it was the discipline that brought him over to the UK to study at the AA in 1964. He is painfully aware that masterplans are hidden works and takes care to remind me to mention the practice's South Bank masterplan which in effect released the undercrofts around the Royal Festival Hall from the drudgery of service access to create cafe and retail space for the complex even before Allies and Morrison was engaged for the refurbishment.

At the University of East Anglia, Mather was commissioned for a computer studies building, planned as the final addition to the campus. Shortly after the building was cancelled, then resurrected in another form, Mather drew up a 25-year masterplan for the campus on which he eventually built four buildings. 'This often happens in universities,' he says, 'though they think they don't need more buildings - and even say so.'

The practice's latest university building is a 16m² greenhouse at Corpus Christi College in Oxford. It is distilled essence of Mather: generous, stylish, strategic; beautiful. Simultaneously treasuring and enhancing its context, it features large plates of glass on a stone plinth and, fortunately, a gardener who clearly feels at home having his assortment of pots on display. Mather's details and materials are a refreshing and sympathetic counterpoint to the solid historic forms he often finds himself working next to. Glazing is not overused nor treated as invisible but introduced to add precision and light; vertically bonded brick at Keble plays around with Butterfield's polychromatic effect.

I suggest to Mather that he draws out the preciousness of his context, the Art and Design Academy in Liverpool wrapping itself devotedly around the precinct of the Metropolitan Cathedral; the cathedral co-opted into the School of Architecture at Lincoln. He laughs: 'Sounds a good remark, I'll agree with it.'

Mather admits he has been lucky to be working in a time when his sort of modernism has been increasingly accepted by clients. 'When I started to be a modern architect no one wanted that, they wanted reproductions,' he says. When he came into the university world he also discovered a new brand of client sitting on building committees. 'I quite like working with academics; you can debate with them and can talk to them from first principles,' he says. But it was the shift from restaurants and fit-outs that he felt most aware of all those years ago, the sense of longevity. 'I like to know the buildings are not ephemeral.'

Mather looks out onto the practice's little roof garden. The small group of architects who were lunching out there have now buried themselves in the busy offices upstairs. 'I missed the outdoor life when I came to the UK. I have always loved the idea of roof gardens and a nice cafe, but people didn't believe you could do terraces here.'

Since then Mather has created landscapes in restaurants, museums and galleries. The outdoor room, courtyard, roof garden, quad, are part of Mather's make-up, moulding his buildings as much as the functions within them. And somehow he has always managed to make them part of his university projects. A rooftop garden in Liverpool, a raised terrace at Corpus Christi, courtyards at UEA. Mather hates the idea of landscape as infill. 'Our buildings are always place-making buildings. It is important you think of every centimetre. I find how a building sits in a landscape as satisfying as the building itself.'

Mather seems of a younger generation than Norman Foster, or university stalwarts such as the partners at ABK, yet at 71 he is within an academic year or two of them. Perhaps it is because his most significant and celebrated projects have been in recent years rather than at the beginning of his career. Does he have any plans for retirement? Smilingly, with a firm shake of his head, he explains that he is now getting some of the most exciting projects of his career. In Virginia, there is a 9300m² extension to the Museum of Fine Arts, along with a sculpture garden; in Oxford the 10-year-long haul of the £47m Ashmolean extension is coming to completion and Keble's new quad is due for submission to planning shortly.

A whole generation of students will grow up through his buildings, and with two architecture schools under his belt he will exert a strong influence on the architecture of the future as well. For humane modernism they couldn't do better than learn from Rick Mather.

Eleanor Young