Developers and local authorities will have to fit more homes on to every acre of land if Dublin's housing and traffic crises are to be resolved, a conference heard yesterday.
Housing subsidies may also have to be introduced, the conference on the housing crisis, organised by the Royal Institute of the Architects of Ireland and the Irish Planning Institute, heard.
In Dublin the back-to-back, detached or semi-detached house design, which has dominated urban planning over the past 20 years, gives densities ranging from six to 10 houses per acre, Mr Peter Bacon, the author of the Bacon Report on House Prices, told the conference.
A survey prepared for the Dublin city and county managers in January identified space for 79,314 housing units at current density levels, he said. If this density was increased to 13 homes per acre, housing supply in the region could be increased to 91,225 units.
This would help to keep house prices stable, he said.
Mr Bacon said South Dublin County Council is now applying a density of 13 dwellings per acre.
Densities higher than that would require different dwelling types, including apartments, duplexes and single-frontage houses.
High density did not have to mean high rise, Mr Eoin O Cofaigh, president of the RIAI, told the conference.
In many areas of Dublin, people lived in terraced houses in "desirable" areas such as Terenure with a density of 20 houses to the acre. In Stoneybatter, the density was 40 houses to the acre.
High-density planning would reduce the city's traffic problems, he said.
The present relatively low numbers of houses per acre meant insufficient customers for public transport and other social facilities.
"Higher densities should mean shorter distances to shops, schools, churches and other social facilities as the numbers of people required to support them can be located in a smaller catchment area."
Making more public transport, facilities and jobs available locally would help Ireland to meet environmental standards.
"Ireland has already reached its carbon dioxide emissions allowances for the year 2012, as agreed at the Kyoto Conference," he said.
He suggested that some of the "windswept grazing spaces" around 1970s housing estates on the peripheries of towns and cities might also be built on.
As many as 50 per cent of Dublin households may need some form of housing subsidy in the future, the conference was told in a presentation by Mr James Pike, chairman of the RIAI Housing Taskforce and Mr Hendrik van der Kamp, immediate past president of the Irish Planning Institute.
"The issue of affordable housing has to be addressed," Mr Pike said. "A recent study in London showed that 50 per cent of households needed some form of subsidy.
"It seems very likely that this is going to be the case in Dublin also. In addition, the present system of public housing is much too divisive, neither can it meet the demand."