A population boom is predicted for Perth's fringe suburbs, but what do you lose or gain by moving there?

While affordable housing, a backyard and the promise of infrastructure may seem attractive, long commutes, car costs and maintaining a large home can see the Australian dream become a nightmare.

Data from demography consultants .id forecasts Wanneroo's population will almost double by 2041 to 400,000, while Kwinana will grow at a similar rate to reach 80,000 in 2036.

By comparison, the city of Perth is predicted to grow at half the rate from 28,000 to just 41,000 in a similar time period.

Rise of the 'dormitory suburb'

Speaking on ABC Radio Perth's Focus, Curtin University's Head of Urban and Regional Planning Shane Greive said parts of outer Perth had become "dormitory suburbs".

"They've been left behind by those who went to work and really, they're places primarily for sleeping," Dr Greive said.

"There'll be some lawnmower activity on the weekend, but five days a week from 7am to 7pm, they've emptied out. They're almost like ghost towns."

Dr Grieve said while there was a "nappy valley" of mothers looking after young children in these areas, that presence ended once children reached school age and mothers started looking for work.

"Then mum's gone to work, dad's gone to work, kids have gone to school, it's empty," Dr Greive said.

"I'm not suggesting these places are unsafe, but for burglaries, risk is going to go up if there are no neighbours around."

Architect Arianne Prevost said she was concerned the lack of people and architectural diversity in some outer suburbs could also have an impact on people's mental health.

"They're all the same in their connectivity together, they've all got the same 17-degree pitched roofs, they've got that look in there, and I wonder how [people] feel in those houses," she said.

"There's no individuality or personality that necessarily belongs to that person … where is the love in the house itself?

"You don't need a backyard if you've got an alternative like a park down the road or a cul-de-sac."

Affordable housing vs affordable living

Dr Greive said people may choose house and land packages because they are priced out of inner-city suburbs, but the costs of living there, such as commuting, could add up.

"If it's an hour-and-a-half one way, that's three hours gone [a day], that's 15 hours [a week]," Dr Grieve said.

Experts say long commutes and the cost of running a car can outweigh the affordable housing. ( ABC )

"Being far away from employment parts is actually quite difficult for part-time workers because you're doing the same work in a different way.

"A little bit of proximity to where you can work and live can help with family economies."

Dr Greive said when weighing up affordability, the cost of running a car was significant.

He also encouraged people to think about what stage of life their children were at, citing the "live-in" boyfriends or girlfriends than can appear as teenagers grow older.

Ms Prevost said the lack of services or housing types in some outer areas could exclude certain types of people from living there.

"The affordability, the demographic of the type of person who's actually going out to these areas is all the same," Ms Prevost said.

"You get young people who are starting off in life, they have young children, they all go to the same place, the place is full of them so they don't have neighbour next to them who's elderly.

"You need a variation of the demographics — so you've got the elderly, you've got the young, the adolescents — to make actually make a proper city and a community."

Embracing the tiny house movement

Tony Pennells moved from a 350 square metre double-story house in Dianella to an apartment in Claremont four years ago with his wife and two children, then aged 15 and 17.

He had been following the tiny house movement in the United States for years and decided to downsize after a frightening home invasion.

Mr Pennells said apart from the occasional lack of living space for entertaining, life was now far better and far simpler.

Apartment-dweller Tony Pennells, architect Arianne Prevost and Curtin University's Dr Shane Greive. ( ABC Radio Perth: Jo Trilling )

"We've got neighbours around us, we've got people around us who we know and that makes a large difference," Mr Pennells said.

"Tighter community, use of public transport increased, [it's] definitely a nicer way to live."

Mr Pennells pointed out Perth's version of "normal" had shifted.

"The average Perth house in 1980 was 140 square metres and our families were bigger back then … now normal is 245 square metres," Mr Penells said.

Community does exist on fringes: mayor

The Mayor of Wanneroo, Tracey Roberts, said the city has been planning for population growth up to the Two Rocks area for decades.

She rejected that residents in fringe suburbs were lonely or isolated.

"People really do feel that sense of place and sense of belonging and they can reach out to people," Ms Roberts said.

"They have the facilities and services … that's what we're prioritising from a city perspective."

Ms Roberts said she was pleased the State Government had committed to extending the Joondalup trainline to Yanchep, but she wanted to see the Mitchell Freeway reach further north.

"[Improved transport] would give confidence for businesses to invest in the area," Ms Roberts said.

However Dr Greive said he had not seen any example of decentralisation succeeding, citing moves out of the city from agencies including Landgate and the ATO which were then reversed.

"Local employment does not actually mean the residents get those jobs, it means someone else travels in to get them as well," he said.

"The [Australian Taxation Office] moved to Cannington, they came back to the city — these things have been trialled and people come back with their tail between their legs."