An interesting and frustrating thing about the housing debate is that it’s between groups of people whose minds work very differently. 

Many talents are needed to make a city. You need an architect’s creative and careful eye; a banker’s cash flow projections; engineers to optimise traffic flows; planners to get designs working for the common good; economists to make sure space is used efficiently; developers’ appetite for risk and ability to drag a project over the line. 

Economists and developers think in quantities. Planners and architects think in qualities. A city designed entirely by economists would lack soul. One designed entirely by architects and planners wouldn’t work. A good system provides a framework for everyone to chip in.

The problem is that when a system breaks down, as it has in Ireland, all the stakeholders see the world very differently and they all talk across each other.

A flashpoint between the two camps is the question of density and tall buildings.

Architects and planners dislike modern tall buildings on mainly aesthetic and design grounds. Tall buildings are ugly, they cast long shadows, they don’t provide a sense of enclosure, they don’t let people have front doors — which helps build community, they don’t allow light in very well, and they use a lot of energy. For all these reasons and more, architects and planners prefer gentle density — buildings of 6-8 stories.

Economists are more receptive to tall buildings because they allow greater density in high-demand locations. Tall buildings in high-demand locations are an efficient use of land, and that makes the economists happy. Questions of design are secondary to them.

It’s fair to say Lorcan Sirr, a TUD lecturer, reflected the urban planner perspective in a recent letter to The Irish Times when he said: “Dublin compares favourably with several major cities often used as examples of appropriate urban population density.”

I am here to put forward the opposite view: Dublin needs to get much more dense, both in the city centre and the suburbs.

The city centre is not dense

Alasdair Rae, a researcher, put together a list of the densest square kilometres in every country in Europe.

What it shows isn’t the city as a whole, but the densest part of the city. It’s a useful number because it’s surprisingly difficult to compare city densities. There’s no accepted definition of a city, which means any attempt to compare city densities runs aground over the question of where the boundary of the city should be drawn.

The densest square kilometre is a good metric because it tells you about the densest part of urban core. Density usually drops away gradually from the core. So knowing the density of the centre of the core gives a strong hint of the overall density of the city centre.

(I wouldn’t over extrapolate though — the ‘densest km’ number on its own isn’t a reliable signal of the density of the entire city.)

Ranked by density, Ireland’s urban core is the 31st least dense of the 38 European countries I looked at (I left out the Caucuses nations, and micro nations like San Marino or Liechtenstein). To give a bit more context, I created a scatterplot showing density along with each country’s population. As the chart below shows, Ireland’s density is below what you’d expect for a country of its size (hover over the dots to examine the chart – Ireland is one of the ones around the five million population mark). The only countries with lower density than Ireland have much smaller populations. 

The metro area is not dense, either

That’s the core – what about the rest of the city? The following images give a sense of how Dublin’s density compares to peer cities across Europe. Each square is one square kilometre. The yellow squares are the densest, with populations of more than 10,000.

Comparing Dublin with the rest, two things stand out. One is that the core is much less dense than its peers. Dublin has four 1 km squares with a population greater than 10,000; the average number among the rest is 28.

Another point that stands out is that is that Dublin has a lot of low density suburbs of 1-5,000 per kilometre. 

Debates over population density usually run aground because each side wants to draw a boundary that suits their argument. But I think these density maps are fair and inarguable. Dublin is a good bit less dense than comparable European cities.

There is one group of cities Dublin looks a lot like — English cities like Leeds, Manchester and Sheffield. Dublin and English cities are similarly sprawling and car-dependent. 

The level of density is irrelevant, in any case

Having made the case that Dublin isn’t very dense, I will now say that Dublin’s level of density doesn’t really matter, anyway. 

The big problem we have in Dublin is affordability. The solution to affordability problems is to build more. It’s not about the level of density, it’s about the change. 

It doesn’t really matter whether the city is made up of bungalows or towers. If the problem is affordability, the solution is the same — build more. 

New York and Dublin are very different, but in one way they’re the same. Starting in the 1970s, New York strongly reduced the number of planning permissions it granted. For example, in 1960, it issued two-thirds as many planning permissions as it did in the entire decade of the 1990s. As well as that, it reduced the number of tall buildings it allowed. Not long after, prices started rising. Between 1984 and 2020, the price per square foot of an apartment in the city rose more than 300 per cent.

Whether in New York or Dublin, there are ultimately only two ways to improve affordability: either make buildings taller or cover more of the ground with them. Let’s fill the city with buildings.