As a national housing and homeless charity, one of Peter McVerry Trust’s central aims is to increase the supply of social housing and alleviate homelessness for the thousands of people currently experiencing it in Ireland.

When it comes to the concept of increasing housing supply, and doing so rapidly, a solution regularly visited is increasing building height restrictions, particularly in Dublin.

At a time when Dublin and Ireland as a whole has tens of thousands of vacant properties and sites (according to Census 2016), is building upwards really the best solution to boosting housing output, maintaining property prices at an affordable level and reducing the number of individuals experiencing homelessness?

Density v Height

When deciding the optimum way to introduce more housing stock and relieve pressure on the housing market, we believe it is vital to consider the existing, vacant properties and sites in areas with housing needs that could be brought back into use and rejuvenate their respective local community, rather than building from scratch.

During Census 2016 the rate of vacant properties per 1,000 inhabitants in Dublin’s four local authorities were recorded – South Dublin (13:1,000), Fingal (17:1,000), Dun Laoghaire/Rathdown (21:1,000), and Dublin City (33:1,000) – giving an average of 21 vacant properties per every 1,000 inhabitants county-wide.

To give those numbers a broader context, results from Census 2016 showed the population of Dublin’s four local authority areas increased by 5.7%, or 72,333 people, between 2011 and 2016, resulting in a total population of 1,345,402.

In addition to that, the CSO* estimates there will be 400,000 more people living in Dublin by 2030 and 600,000 more by 2050, thus creating a very tangible and urgent need to reintroduce existing properties.

Compare Dublin’s density to the likes of Copenhagen, where there are roughly 400,000 more people living in the equivalent of the area between Dublin’s canals, and an inefficient use of vacant space in the capital can be observed.

The approach for coping with density in Copenhagen is that they first put in the infrastructure, like transport, schools and supermarkets, which makes communities within the city more livable and sustainable.

Alongside this are high-density micro plans for areas within the city, which ensures that there will be the population to sustain the infrastructure and services introduced during the phase above.

Meanwhile, in 2018, there were 333 vacant units recorded in Copenhagen as Denmark has a system that encourages people to use property efficiently, mainly through taxation.

Given the population and development pressures predicted by the CSO, a greater focus is needed on bringing existing vacant properties back into use and making Dublin suitable for accommodating greater density, like Copenhagen, rather than height.

Rising Costs

It’s widely acknowledged that modern, high-rise developments are very expensive to both build and occupy.

When a building passes six storeys in height a number of additional costs start to pile up, including increased fire safety, structural requirements and the high cost of maintenance involved in service charges and sinking funds, to name a few.

Further to that, building expensive high-rise buildings also inflates the value of the land upon which it is built. When a modern high-rise is constructed, its premium sale value and rental yield per unit, land value and overall value of the development set a benchmark for similar buildings developed thereafter, thus becoming the rising tide that lifts all boats and creating greater price inequality and affordability issues in the housing market.

With the above costs considered, developments higher than six storeys are rendered ineffective in terms of creating more affordable and social housing.

Beyond the building itself, community facilities, emergency services and infrastructure around a high-rise building must also be taken into consideration. Again, Copenhagen’s approach to introducing infrastructure to cope with density sets a blueprint for Dublin to follow.

If hundreds of apartments are built and tenanted on a single site in the city centre, does Dublin have the transport, parking, green space and facilities such as schools and supermarkets to create a livable community, both for those already living in the area and those occupying the new building?

Further to that, how much will the likes of Dublin Fire Brigade need to reinvest in its fleet if they are to assure tenants of new high-rises that in the event of an emergency, their trucks can access the upper floors? Currently, this would not be possible.

Environmental Impact

With radical change required to hit Ireland’s climate targets over the coming decades, a more efficient approach to developing property will play an integral role in achieving these aims.

Specifically, these goals are to cut CO2 emissions by at least 80%, compared to 1990 levels, by 2050 from the building, electricity and transport sectors.

In terms of building new homes, a report titled “New Tricks with Old Bricks” by Empty Homes Agency in the UK found the construction of a new house generated 50 tonnes of CO2, but the renovation of an existing house emitted only 15 tonnes in comparison.

For newly built high-rises, the development’s embodied CO2 has a number of unique contributing factors which must be considered when contrasting their carbon footprint with reusing vacant, low or mid-rise building properties, according to Orla Hegarty, assistant professor in the UCD School of Architecture.

These include, (i) additional construction costs including weightier foundations and super-structure, (ii) heavier/higher specification facade due to wind-loading, (iii) higher specification lifts/extra lifts, stairs, water pumping equipment, higher spec. fire alarm, fire suppression and smoke venting systems, (iv) lower nett/gross floor area in high rise (due to loss of floor space for services/ water/ drainage runs to upper floors, additional lifts/ stairs, heavier facade etc., (v) additional running costs of high speed lifts, water pumping, and systems mentioned above, (vi) additional maintenance and repair costs (working at height/access problems), (vii) additional cleaning for more common areas etc.

Once constructed, high-rise buildings use more energy per square-metre than their low and mid-rise equivalents, as well as emitting twice as much carbon, according to University College London’s Energy Institute.

The same research found that electricity use is nearly two and a half times greater in buildings of 20 storeys or more, compared with buildings of six storeys or fewer. Furthermore, gas consumption is 40% greater.

With the current stock of vacant and under-used properties in Dublin, it is vital that we assess our existing resources, optimise it for sustainable, affordable and social housing, and develop liveable communities within the city. Until such a point is reached that our existing stock is used, then the approach to increasing Dublin’s skyline could be revisited.

Peter McVerry Trust’s Empty Homes Initiatives are attempting to secure properties under the Repair and Leasing Scheme and Buy and Renew Scheme as part of Rebuilding Ireland. However, we are equally happy to speak to owners about securing their properties through Long Term Social Leasing.

To get in touch email us at emptyhomes@pmvtrust.ie or call 01 823 0776.

* The CSO compiles a wide range of statistics to meet national, EU and other international requirements. Most of the information is collected directly by the CSO from households and businesses. The samples used for this purpose must be representative and a high response is necessary to ensure that the derived results are accurate and reliable, according to the CSO.