Amongst all notions of what it means to be Australian, few are etched as strongly into the national psyche as getting married, having children and buying your own home on a quarter acre block.

First conceived during the baby boomer period after the Second World War amid a desire to establish a sense of security and belonging following a period of hardship and uncertainty, the notion of the Great Australian Dream has evolved over time and in recent decades has been encapsulated in television series such as “Neighbours.”

Yet the nature of housing being provided is changing. Despite having eased back since the global financial crisis, the average floor area of new detached housing rose by 48.5 per cent from 162.4 square metres in 1984/85 to 241.1 square metres in 2012/13, according to ABS figures. Even as average household sizes dropped from 3.1 to 2.6, the average number of bedrooms per dwelling in Australia increased from 2.8 in 1976 to 3.1 in 2009-10, whilst the number of dwellings with four or more bedrooms rose from 17 per cent to more than three in 10.

Indeed, as of 2009/10, a quick spreadsheet calculation indicates that Australia had at least 25.6 million bedrooms even though we only had 22 million people, meaning that even if all parents and children slept in completely separate rooms, the nation would have had more than three million bedrooms lying empty each night.

Simultaneously, median lot sizes fell 29 per cent in the decade to 2014 and contracted by a further 3.6 per cent last year, according to data from the Urban Development Institute of Australia. Bottom line: even as household sizes contract and affordability challenges grow, Australia is building larger houses on smaller blocks.

On the positive side, this has benefits not only from the point of view of developers in terms of squeezing greater profit out of a given area of land holding but also more broadly in terms of lower costs associated with the land component of new housing and a lesser impact in terms of land usage and urban sprawl. Also, smaller backyards may be suitable for families who would rather spend more time with children than doing yardwork.

On the flip side, however, larger house sizes add to the actual cost of construction. Take for example, your standard single level, brick veneer home with an off-the-shelf design on a level block. According to a table on the BMT quantity surveying web site, average construction costs per square metre on a gross floor area basis would amount to around $1,290. Adding in an extra floor (same number of bedrooms) would add $50 per square metre, whilst the addition of an extra bedroom and a ‘unique’ design would see costs blow out to $1,835/$1,980 for a single/double storey home.

In a recent research project, RMIT research fellow Travis Moore, University College research fellow John Edward Morrissey and Lancaster University senior lecturer in sustainable design Stephen Clune noted that if you reduced the size of an average 6-star 250 square metre home in Victoria by between five and 10 per cent, you would knock around $20,000 off the $195,000 cost of building (excluding land). In an environment of housing affordability challenges, larger house sizes are surely adding needlessly to costs.

Smaller backyards, meanwhile, restrict the amount of space available in which outdoor activities can occur in a safe environment. That – combined with increasing number of rooms inside – may potentially see children progressively spend greater amounts of time indoors. In addition, higher numbers of double storey dwellings have obvious impacts for accessibility and create overshadowing, whilst modern double garage arrangements reduce the number of opportunities for serendipitous interaction with neighbours.

Does this matter? Speaking primarily about the social impacts of what he calls “McMansions,” University of Technology Sydney associate dean (research) Peter McNeill argues that it does. In an article on The Conversation in 2013, McNeill complained about the “horrible waste of space and resources consumed by the ever-expanding house on the large suburban block.” Much of the move toward greater house size, McNeill argued, was more a function of evolution toward a consumer-oriented society and a symbol of status as much as a reflection of need. He added that many of the houses going up bore no relation to the scale or context of the surrounding environment. Moreover, McNeill argued, a ‘retreat’ into the indoor areas of our homes could precipitate a more ‘atomised’ existence where we become withdrawn from neighbors and local communities.

Moore, meanwhile, says there is a mismatch between the type of product on offer and the need of young families starting out on the housing market.

“There is definitely a mismatch between the product on offer and the people that are starting new families,” he said. “Either they have to have a three, four or five bedroom house or there is not going to be anything else for them other than a tiny kind of apartment. We need to try to provide a range of options for different families’ requirements and needs.”

Moore says the phenomenon of larger houses on smaller blocks brings with it a number of drawbacks. At a localised level, residents in some outer urban areas were finding unexpected problems with localised traffic congestion, he said, whilst greater use of double storey layouts was not only adding cost but impacting usability and livability, especially as upstairs bedrooms are generally hotter in summer.

Nevertheless, he says, some of the challenges can be addressed. Issues surrounding child exercise and community interaction can largely be dealt with through well designed communities with sufficient access to shared facilities such as parks, he said, whilst there are opportunities for cost to be addressed through innovative construction methods such as 3D printing and prefabrication.

Whilst acknowledging that a large part of the push toward larger houses is being driven by developers, Moore says consumers also need to think carefully about what they really need and want from their home.

“It’s about consumers trying to understand a bit more about what they actually need and want and what that means in terms of impact for them,” he said.

“So if you buy a large house, it’s going to cost a certain amount to clean, maintain and all these types of things whereas perhaps in a smaller house, you might not have that extra bedroom or the second living area or what have you and so it’s likely to be more affordable.

“I think it’s a little bit about consumers understanding some of those through-life impacts of their housing choice a little bit better.”

Australian developers are building larger houses on smaller blocks.

Whether or not this is beneficial is open to debate.