This Vancouver den for rent is so small the door won't close. It's also completely legal.

In Vancouver's notoriously expensive rental market an expert says the decision to rent out a den is largely driven by desperation.

It's not unusual for prospective renters searching out affordable options in Vancouver to come across listings where someone in search of a roommate has crammed a single bed into a windowless, downtown den. But are these arrangements legal?

In the latest example, a tiny space is advertised on Craigslist for $650 a month.

"(A) very private space with door for privacy and curtain," the listing reads, noting that it is located in a two-bedroom unit in a Yaletown high-rise that would be shared with two other people.

However, while there may be both a door and a curtain, only one of them can be closed because the mattress that dominates the space – despite its small size – leaves no room to close the door.

There is no closet or dresser but there is a narrow, free-standing shelf, along with several others mounted on the walls.

"Good for student/international student or someone with small luggage who needs a place to sleep," the ad continues.

No photos of the building are provided but the ad describes it as on an upper floor of an "upscale" tower with an onsite pool, sauna, steam room, gym and activity room. The ad also says the current tenants are looking for someone who is quiet, clean, respectful, with no pets, who does not drink or smoke and will not bring home any visitors.

IS THIS LEGAL?

While renting out diminutive digs like these might seem like it would violate regulations, one expert says these arrangements are actually legal.

Robert Patterson, a lawyer with the Tenant Resource Advisory Council, says situations where someone is seeking a roommate are not restricted by provincial legislation.

"Who uses what room for sleeping, or what have you -- however that's arranged -- doesn't run afoul of the Residential Tenancy Act. Unless there are so many people in the unit that it becomes an unreasonable number, and then the landlord has the right to end the tenancy for that," he explains.

As far as municipal by-laws that lay out things like building and fire codes, Patterson says those apply to developers or homeowners trying to get approval for the construction of new suites and he is unaware of any restrictions on how the space can be used once built and rented out.

"Generally speaking, if I'm someone living in a rental unit and I bring in roommates, I'm permitted to do that," he says.

While Patterson says there are examples of landlords "aggressively subdividing units into aggressively tiny, tiny spaces" as a way of "profiteering" off of the housing affordability crisis, he says listings like these illustrate an entirely different problem.

Both the people advertising these spaces and the people who may be considering renting them, Patterson says, are navigating a rental market where the average studio rents for $2,000 a month and the vacancy rate remains stubbornly low.

"There's simply nothing available at an affordable rate in their community, that's why people will turn to something like this," he says.

"People who are splitting rental units in all these ways, it's often because they can't afford the rents they have to pay. People, because they can't find anything affordable, they'll take something that's unaffordable and hope and try the best they can to get other people to split the cost with them."

While sharing accommodations is an option many people seek out in order to share the burden of sky-high rents, Patterson points out that it also comes with a built-in level of risk.

"Anytime you enter into a roommate relationship with someone, you open yourself up to potential liability to each other for things that might go wrong," he says.

"It just goes to show that people are so desperate for housing, so desperate and unable to pay their own rent that people on both sides of this equation are willing to take that risk."

CTV News Vancouver has reached out to the poster of the ad to get more information about this rental but did not receive a reply.

DESPERATION LIKELY DRIVING THESE LISTINGS: EXPERT

While the central location and amenities promised in the Craigslist ad may entice some renters to compromise on space and privacy, Patterson says this rental illustrates one of the biggest drivers of the housing crisis.

"If someone's seriously considering that small of a room for $650 they are not going to be able to afford the luxury supply units, which are the only things coming onto the market, the only things which are being built in any reasonable numbers," he says.

A substantial investment in co-op affordable and non-market options is, according to Patterson, the only strategy that will successfully drive down prices in Canada's most expensive market.