Conferences: Development densities in urban areas must be increased if Ireland is to benefit from heavy investment in road and rail infrastructure.

Forcing low densities - as will arise from new planning guidelines - may also have the effect of further depressing house completions in the city, the annual conference of the Society of Chartered Surveyors has heard.

The society held its eighth national meeting last Thursday in Dublin, where its president Felix McKenna spoke about the need for more joined up thinking when it came to land and infrastructural development.

"The key issue to my mind in looking at urban development and sustainable land use is the relationship between planning, land use and public transportation," McKenna said.

The key was "to find a formula which enables the required level of development necessary to support the growing population and economy to continue, and to do so in a manner which optimises the limited resource of development land".

The conference was opened by the Minister for the Environment and Local Government John Gormley. He said the conference was "timely and relevant" given the slowdown experienced this year by the construction sector.

The value of construction output had peaked at €35.5 billion in 2006 and was forecast to decline modestly in real terms by 1.5 per cent in 2007 and by 6.2 per cent in 2008, with positive growth expected in 2009, Gormley said. "This does not portray an industry in crisis, it portrays an industry in transition to more sustainable levels of activity."

He said that development plans were the appropriate vehicle to find the balance between meeting the needs of the community while preserving environmental sustainability. "Housing and urban design must be approached in a planned and sustainable manner that is conducive to improving social integration and enhancing the built environment. It must also ensure the best use of the country's land resources by integrating housing provision with essential transport links, public utilities and the full range of social and community amenities," Gormley said.

He promised updated planning guidelines for residential development, saying he would "issue these for public consultation by the end of this year".

Relaxing density limits would have the twin effects of maintaining the throughput of housing units while also supporting state investment in infrastructure, McKenna said. "Public transport networks, which everyone agrees are desirable, rely on volumes of users, and those volumes can best be achieved through a more dense urban form," said McKenna, who directs property services at Eircom.

"We can either continue with the low-rise sprawling urban form which will not support the requisite investment in public transport, or we can adopt a more dense urban form, which supports investment, and a more sustainable form of land use."

This would become particularly important given changes brought through in Sustainable urban housing: design standards for apartments published by the Department of Environment, Heritage and Local Government in January. The guidelines are positive in that they require a more "family-friendly" housing unit in the city, but they will likely have a negative impact on development activity, McKenna warned.

"In practice, it is estimated that adherence to the guidelines could add as much as 20 per cent to the cost of the average two-bed apartment or townhouse, and applying current development plan site densities, the guidelines are likely to reduce the number of units permissible on a site by as much as 15 per cent," he said. "It may well be that a relaxation of development densities is an appropriate solution to deliver the quality of residential environment sought in accordance with the principles of sustainability."

He said that a similar relaxation of restrictions on "one-off"housing was also needed. Having been brought up in Monaghan he had experience of the importance of rural housing starts, he said.

"Vibrant rural communities require people, and in particular young people, to live in rural areas. So the challenge here is to find a planning model that strikes a balance between encouraging people to live in the countryside, and respects the toll that such living may place on natural resources."

Derry Scully, managing partner of Bruce Shaw Partnership, addressed delegates on the impact of sustainability on the cost of commercial and residential buildings.

While research had shown that modern sustainable buildings required an initial extra capital cost of 6 per cent, there were significant energy savings for occupiers. The savings in an "A" rated building compared to a conventional air-conditioned office "could be as much as €20 per sq m per year", Scully said. "For a 25,000sq m office this is a potential saving of €500,000 per year."

James Nugent, director of Lisney, discussed the economics of sustainable development, and the chairman of the London office agency department of DTZ, John Forrester, presented a paper on the impact of sustainability on commercial property.