Housing crisis will force more families into private renting
One in four households in Wales could be living in rented accommodation by 2025, it is predicted.
Hundreds of thousands of young families who cannot afford to become homeowners face an insecure future, says independent housing consultant Tamsin Stirling.
She examined the issue for BBC Wales' Week In Week Out programme.
Figures reveal the percentage of people renting has doubled in recent years from 7% to 14%.
Ms Stirling said: "There are number of predictions which say by 2020 we are looking possibly at an average of 20% of households renting in the private sector and that's an average across Wales.
"So for different areas you could be looking at more than that. Cardiff is probably already around 20%."
If current trends continued, around 25% of households will be renting by the middle of the next decade, with 30% renting in Cardiff.
The programme focused on people living in Tintern Street, Canton, Cardiff, where 30% are now renting - 20 years ago most would have been homeowners.
Young families told the programme almost half their income is spent on rent.
Resident Sallie Morse, who lives in Tintern Street with her two children, has been struggling to pay her rent.
"Basically, it's been rent and not much food and with my job as a care worker I need petrol money. I've got a court case to see how I can repay my debts to the landlord," the care worker said.
"He's applied for us to be evicted as well as the rent arrears."
Ms Stirling said rent has soared because of increased demand.
"There is a general consensus that in order to be affordable, housing costs, be they mortgage or rent, shouldn't be more than 25% of gross income," she said.
"If you're on an average income in Wales you're already spending more than that. And if you're on a lower income again then you're moving up from a third to nearer 40% of your gross annual income."
The Welsh government plans to pass Wales' first housing act next year to tackle the housing crisis.
One solution is for more families to see renting as a long-term situation.
Housing Minister Huw Lewis said tenants' rights will be looked at in separate legislation but he accepts the housing crisis poses a challenge to the government.
"I don't think everyone really understands quite how serious this could become," he added.
"Pressures on people over the next few years are only going to grow, pressure on the sector is only going to grow. The whole question of affordability is going to be at the forefront of the minds of hundreds of thousands of families across Wales and we are moving to react to that."
Week In Week Out is broadcast on BBC One Wales 22:35 BST on Tuesday.