ROBERT DALZIEL, a London-based architect, has always considered contemporary housing in Britain to be deficient. After years spent researching urban housing around the world with Sheila Qureshi-Cortale, a fellow architect, the pair collected their findings in a book. “A House in the City” evaluates the various examples, new and old, high-rise and low. Mr Dalziel was then inspired to design Rational House, a new concept for low-rise, high-density and sustainable city homes in Britain. According to Mr Dalziel, building low and compact but to a high standard is a feasible alternative to large-scale residential blocks and towers, which alienate inhabitants and integrate poorly into the surrounding urban environment. The first prototype was completed in West London last year; a sustainable, adaptable and fast solution; the shell of the house is prefabricated off-site from recycled materials and can be raised in two weeks. Mr Dalziel spoke with The Economist about his research and what makes successful urban housing. Why is there a common misconception that high-density means multi-storey tower blocks?

It’s a hangover from the post-war period when you had slum clearance. Do you know the Roehampton Estate in London? It’s that famous Greater London Council-designed estate, modelled on Le Corbusier’s concept building in Marseille known as Cité Radieuse. It’s made up of a series of long, linear high-rise blocks set in gardens. When this was built people thought it was high-density, but actually the density of Roehampton is about 350 habitable rooms per hectare, a third of the density of a typical residential street or neighbourhood in central Paris, where seven-storey blocks predominate. This is so striking.

You include 54 case studies in the book, and conclude that high-rise developments have many disadvantages such as consuming too much energy, costing a lot to maintain and not being very flexible.

In the chapter called “density in urban form” we draw attention to the fact that you can get very high densities with low-rise housing by using some of the clever tricks that have been used in some of the archetypes. The disadvantages with high rises are many and it’s not just about them being too costly to build and maintain. It’s more about the fact that as soon as you go high you lose a sense of community because you detach yourself from the street. I think the general conclusion was that there is still a presumption in design that to get high densities you need to go very tall. The rather surprising conclusion was that you don’t need to.

What are the most interesting examples that achieve low-rise, high-density design?

There is a very interesting housing type called the vecindades in Mexico City, where they build dwellings back-to-back and side-to-side with little courtyards and little mews streets. It’s this idea that you don’t need a back garden and a front garden but you can still stick with your two-storey format and produce a courtyard that gives you some private outdoor space.

Another very interesting type was the Lilong House, a Shanghai archetype. The Lilong house is different in that it tends to be organised in rows with quite narrow pedestrian lanes. So you put the backs of one set of houses next to the fronts of the next set of houses so you don’t have problems of overlooking and privacy. You get to the lanes by going from a busy street to a secondary street to a lane and then sometimes to a courtyard. So you have quiet and privacy and tranquillity and, yet again, you’ve got very high density but you are right in the middle of things.

In the book you talk about the importance of the threshold. Can you explain more about this? What we perceived is that there is this psychological need for detachment from the busy streets of the city. This is created in a variety of ways. One way you can create it is like the New York brownstones, which have a semi-basement and some steps up, so you have a gulf between the street and your house. That creates a detachment in a very effective way and it’s also the way it’s done in Georgian housing. But it means that the street becomes a very public space, it’s not used in any private way. With something like the "potato rows" houses in Copenhagen [terraced houses on narrow streets, filled with picnic tables, trees and benches that become shared spaces] the street is quiet enough that you don’t have to create this physical detachment from the street. And then people start to take over the street as part of their private space. The problem with most modern housing is that either it doesn’t create any detachment at all—it’s just doors on to the street—or alternatively it’s tall residential blocks which detach you from the street but then you have to get into a lift, and walk along several corridors before you reach your front door. So you’ve got all this weird anonymous space, which is neither public nor private. This is what you call "intermediate space" in the book.

Yes, and it’s universally disliked. What we found is that the people we interviewed living in high-rises all said without exception that it was a temporary situation, it was convenient and the view was good but what they really wanted was to get a place closer to the ground.

So individual access and a front door are really important?

Ideally. But if it’s a larger construction or house, then an element of subdivision, providing you are not going up beyond four or five stories, is inevitable. But at least you have a connection to the street which is between you and a few other family groupings, and you are not going through all these long corridors and anonymous staircases, lifts and so on.

Which housing types work best for bringing in light?

The cleverest way is the oriental way, a courtyard. It’s extraordinary the amount of light you get if you expose the sky. You don’t need to have a long view; you just need to expose the sky to a private area.

What other housing types are innovative or interesting?

There is something called Baugruppen, a new initiative in Berlin where a group of middle-class people get together and hire an architect, buy a site and build for themselves, cutting out the developer profit. This is a very interesting idea. It’s not uncommon in Austria and Germany and there’s a new government initiative in Britain called the Community Right to Build where the government is trying to encourage this to happen. It’s such a brilliant way of funding and building high-quality housing at low cost.

A House in the City: Home Truths in Urban Architecture. By Robert Dalziel and Sheila Qureshi-Cortale. RIBA Publishing; 176 pages; £29.99