Anybody with an interest in design can name a great modernist building or a great piece of modernist furniture. But what about a public space? Or a work of landscape design?

In Toronto, the city’s most famous public space, Nathan Phillips Square, is a modernist classic that is much loved, indeed one of the best spaces of its kind in the world. But it’s far from perfect, and now it’s getting a renovation that sets an example for how such projects can be updated: with green roofs, ecologically sensitive planting, a better mix of functions and better connections with the city.

A rendering of the finished square, as seen from the southwest.

Some background: Nathan Phillips Square sits in front of Toronto’s City Hall (more info here). The products of an international competition in 1958 (beating an entry by I.M. Pei), they form a beautiful ensemble of curvaceous Scandinavian modern. City Hall’s two curved towers rise from a rectangular base, and wrap around a round council chamber. The concrete-paved square holds a pool that becomes a skating rink in winter, cradled by a set of flowing arches – and the square itself flows up a ramp to the top of City Hall’s first floor, and from there to an elevated walkway.

The square hasn’t survived as well as the building. The Finnish architect, Viljo Revell, died in 1964 before it could be completed. And though the square has become Toronto’s central gathering place since it opened in 1965, it was always a bit stark and poorly detailed. The elevated walkway was never that great an idea – a largely featureless concrete ribbon – and it was eventually closed. The square features a cheaply built pavilion, a peace garden added in the 1980s by city designers, a temporary stage, and an accumulated mishmash of furniture and service sheds.

Plant Architect, the principal designers of the new scheme, refer to all this stuff as “clutter.” And in a gesture of respect for the original design, they will basically clear the square – but instead of leaving a blank slate, they’ll add a set of subtle and eco-friendly interventions, along with better-quality pavilion buildings. It’s a sensible compromise between the formal purity of the original and the sort of plaza that’s actually comfortable to wander through and linger in. They won a competition that wound up in 2007.

Water features: view looking north, from the southeast corner.

In the square itself, a series of “disappearing fountains” will let visitors get their feet wet, and lighting built into the square will visual interest – all without disturbing the plane of the square.

Green roofs on top of the building’s podium will dramatically reduce the heat island effect and totally transform the elevated spaces. Those are clearly visible on these plans. And in fact the entire square is a green roof in itself, capping a giant parking garage; around the edges, Plant has called for denser plantings of trees that will add shade and green the site.

Also included in this $42-million (Cdn.) project will be new buildings: a new welcome pavilion with bike lockup and stair to underground; a new restaurant; a new pavilion to serve the skating rink; and a permanent theatre.

Info kiosk, southeast corner

Restaurant building, southwest corner

Theatre, looking southwest

Plant, a small firm whose practice produces high-quality architecture, landscape and urban design, will no doubt do a fine job of detailing these buildings. (Architects Shore Tilbe Irwin and Partners are also on the design team.) And the restaurant, in particular, will give more people a reason to linger here. I’m confident that it will be urbane as a city’s main square should be. (The eats will definitely add an alternative to the chip trucks and hot-dog carts that dominate there today.)

Landscape architecture has gone through a great deal of change in the past couple of generations: today’s most innovative parks playfully integrate the natural and the wild, and explicitly build on the urban, industrial and architectural history of their sites. (New York’s High Line is the most high-profile current example. See my piece about it in the Globe and Mail here.)

This project reflects those changes only in subtle ways: the greening of the site, the choice of trees and relatively wild plantings instead of more formal ones. But unlike in contemporary work by West 8, Michael van Valkenburgh Associates or James Corner Field Operations – all currently working in Toronto – there’s nothing radical here, which is a direct response to the city’s competition brief and I think the right attitude in this case. (One of the losing competition entries, by Rogers Marvel Architects, Ken Smith Landscape Architect and duToit Allsopp Hillier, shows how a more edgy approach might have played out here.) As it is, the square will remain a square, and maintain a clear division between the artificial (the plaza) and the natural (the gardens around the edges).

This project is primarily about basic urbanism and about preservation of an old idea – the plaza as a gathering place -  that’s worked well here for 45 years and has a long, proud history. Toronto does not take good care of its modern past, and too often it’s been hostile to the best of contemporary design. This should be a welcome exception.