A white rose among the thorns

It's white and symmetrical, quite unlike any other building near it, and in that particular slice of Battersea in south London, it stands out like a block of vanilla ice-cream on a plate of pie and mash. The minimally detailed post-modern building surely has nothing to do with the light-industrial units along Gwynne Road or the high-rise across the street.

It's white and symmetrical, quite unlike any other building near it, and in that particular slice of Battersea in south London, it stands out like a block of vanilla ice-cream on a plate of pie and mash. The minimally detailed post-modern building surely has nothing to do with the light-industrial units along Gwynne Road or the high-rise across the street.

Surely, number 2 Gwynne Road simply must be a building by architecture's Mr White, the minimalist John Pawson, for a rich client who wanted a posh little gaff down the old manor for his lovely Nan.

It isn't, and not by a long chalk. Number 2 was built for the Ujima housing association, which has a solid track record for innovation in the housing of so-called "problem" tenants and ethnic minorities. The building contains eight self-contained flats - six for special-needs tenants, two for private owners.

Walter Menteth's solution to Ujima's brief was good enough to pick up one of this year's seven Housing Design Awards for completed projects. That the Gwynne Road building did so reflected the award's central theme: sustainability and the ability to "meet the needs and aspirations of future generations as well as our own".

Designing a building to meet aspirations seems a quick-sandish idea. Developers and architects have always delivered aspirational buildings, but they are more often than not pattern-book efforts; off-the-peg rather than tailor-made. And even if individual solutions were available, how many architects have the skill to refract the aspirations of others through the mirror of design?

But the question of sustainable architecture - a ubiquitous but specious expression - can be looked at in a more useful way at Gwynne Road. If anything can be gleaned from Menteth's methods, it is that there can be no off-the-shelf approach to building in an environmentally sensitive manner. Gwynne Road proves something else too: that innovation and reduced building costs - eight well set-out flats for £460,000 - are not mutually exclusive. Menteth and his team have established a reputation for solving problems, and for working from first principles in deciding how best to use building materials.

"We used Gwynne Road as a prototype for a spectrum of materials for the housing association," says Menteth, "so quite a lot of research went into that project. In public housing, budgets are appallingly tight and the restriction in the internal layouts is quite onerous. So the only thing you can do is play with the room volumes. It's a question of jiggling around with the floor-plate."

He also went for a specific ground-plan for the building, and for a particular reason: "The basic form is a rectangle, therefore low surface area to internal volume - plus, it gives the building an identifiable mass." The practical result: sharply reduced heating costs.

In terms of materials and building methods, nothing was ruled out. At Gwynne Road, the site's thick boundary walls are made of caged dry-stone fragments which give an attractively rugged bottom layer to the building's pure elevations; the external walls of the building are dense dry-pressed concrete with an 80mm polystyrene layer glued to the external face, which is then coated with a highly flexible and steam-cleanable acrylic render. Very unusually in new-build housing, the walls are solid and without cavities.

"That thickness and density gives us a seven-hour time-lag in the thermal cycle of the structure," says Menteth. "Once the walls heat up during the day, much of the heat is retained and released overnight."

With the exception of the projecting square corner windows, he has looked for simplicity at almost every turn. The building delivers a distinct graphic impact based on its whiteness, scale and contrasting textures: the gleam of metal-framed windows set into the matt white walls; the flat roofline contrasting sharply with the chunky shards of stone in the wall.

"We also wanted to give the building some scale," says Menteth. "It doesn't look like eight separate properties. It's rather like a Georgian pavilion." The remark is rather tentative, but there's no doubt that Menteth has an ability to deliver a bit of a looker on an apparently dud site. His block of four private flats in London Fields in Hackney, east London, is brilliantly decisive despite a site width of only 3.2m.

Menteth's innovations reflect the fact that he's is a doer who takes nothing for granted, and a thinker whose take on "sustainable" architecture is loosely organic rather than systematically tally-ho.

"Whatever one builds and however one builds, it cannot be sustainable because situations are changing too quickly," he insists. "I believe that the most sustainable way to build is like village architecture - like they used to clear the fields of loose stone to build the habitations. The concrete blocks for Gwynne Road are from Essex, the dry stone came from Oxfordshire.

"At the moment the sustainability debate is led by the belief that, as timber is a crop, it's sustainable. That's all very well, but it's reliant on an international economy where the environmental costs of transport doesn't come into the way people evaluate the issue. Our timber comes from Canada and Scandinavia, but I've never had sufficient data provided to me that builds in the transport costs of structural timber from around the world."

Menteth's views on timber sourcing are debatable. But his quest for singular and sometimes unexpected solutions is beyond criticism. Another project, due to go on site next year in Harringay, is taking re-use of materials to an interesting level - around 30 feet, to be precise.

Ujima's mixed-use development for a large site next to the busy Monument Way in Tottenham Hale in north London will be bounded on two sides by a sound and pollution-absorbing berm with a steep 65-degree slope. The 3-metre thick barrier of demolition rubble will be held in place by metal mesh and overlaid with grass - "almost like putting the rural ethos into the urban fabric, and better than having to pay landfill tax on demolition spoil".

Such grubby matters probably don't intrude on the minds of those architects who derided Gwynne Road: its classical virtues were deemed inappropriate for the location. Perhaps they felt such a building might have been better closer to the river. Somewhere within ambling distance of the funky cafés in Battersea Bridge Road, where aspirations are so much more clear cut.