This week Apollo House, a vacant Nama-owned property on Tara Street, in Dublin 2, was taken over by “concerned citizens” who want to use it to house homeless people. Their response to the widespread homelessness problem highlights a paradox of the current housing crisis.

While more than 6,000 people in Ireland are officially homeless, while a frenzy of building activity struggles to meet housing demand, and while arguments about rising rents convulse Dáil Éireann, numerous buildings in the capital sit empty. Naturally, concerned citizens must wonder why they cannot be used as homes.

Would filling these empty buildings alleviate the crisis?

In theory, yes. Nine per cent of Dublin dwellings – almost 21,000 units, excluding holiday homes, in the city and suburbs – are vacant. (The national rate is even worse, at 13 per cent.)

Many of the city’s buildings date from the 18th and 19th centuries. A large proportion of them, even those originally built as housing, have been converted to commercial use over time. But their desirability as office or other commercial space has been waning for many years.

Businesses increasingly favour purpose-built schemes, often far from the city centre. As a result many of these older properties in the city lie empty.

Some older public-housing schemes are also vacant. In most cases these no longer meet modern living standards, and the trend has been to build anew rather than to renew.

The Celtic Tiger boom did surprisingly little to reduce the number of vacant older buildings. Although lots of new apartments were built and the city centre population grew – from 84,000 in 1991 to 136,000 in 2011 – many older buildings bought up in large batches were left empty and deteriorating after their redevelopment plans fell victim to the crash.

With the current shortage of housing, the vacancy level in the city has moved from being merely a visual blight to being an affront to those in need of homes.

New policies have been introduced to bring older buildings back into use, but they have yet to produce significant results. One such scheme is the Living City Initiative. This tax incentive allows owners of old city houses to claim relief for refurbishment at a rate of 10 per cent a year for 10 years. It came into effect in April 2015, but the response has been disappointing. In the recent budget some of the scheme’s rules were relaxed in an attempt to increase take-up.

“We’ve had 26 applications and we’ve processed four so far,” Paul Clegg of Dublin City Council’s planning department says. “But we’re hoping the changes in the budget will see an increase.”

Applications have mainly been for the restoration and reuse of whole houses, but the council is hoping that more people will apply for the conversion of the upper floors of buildings.

“Studies on Capel Street and South Great George’s Street done at the time of the Living over the Shop scheme” – the forerunner of the Living City Initiative – “showed a large amount of vacant upper-floor space that is being unused,” Helen McNamara, of the council’s active land management unit, says.

“It requires serious marketing, because mostly the retailer is only interested in his own shop and not the space above. But Thomas Street, D’Olier Street and O’Connell Street all have vacant upper floors which, in another city, would be the most attractive places to live.”

The council also plans to start buying derelict and empty properties and has set aside €15 million to do so over the next three years. The council has always had the power to compulsorily purchase properties from the derelict-sites register, but it has done so only rarely.

“It’s so long since we’re acquired property that we’re relearning the process. But we have 10 ready to go, one where we’ve reached terms by agreement and a couple in negotiation with the housing department,” McNamara says.

In many cases just contacting the owners and telling them of an intention to compulsorily purchase the building has had the desired effect, according to Clegg.

“A lot of people came back very smartly, and either rendered the building nonderelict or put it on the market, but there were others where there was no engagement. We contact the reputed owners, but there can be title difficulties, or owners out of the country, or in nursing homes. There’s almost always a human side to these cases.”

The €15 million fund will be a rolling one, and as buildings are sold on it will be replenished. The council has initially concentrated on easy wins – buildings that don’t cost too much and are quick to shift – but it plans to tackle more ambitious projects if the fund is successful, Clegg says.

“We would like to buy more historic buildings, but we need to be prudent: you could blow the entire city budget acquiring these properties.”

Fears about the regulatory burden associated with listed buildings deters buyers from taking them on, particularly when it seems that complying with standards – such as disability access – can conflict with conservation requirements.

Recognising this, the council cut some of the costs of bringing listed buildings back into use three years ago. Where an owner is making an application for the change of use of a building – often the case when a vacant protected structure is being brought back into occupation – they are exempt from development levies. An owner extending a protected structure will pay only half the standard development contribution.

But are the incentives sufficient? The low uptake of schemes seems to indicate that buyers are still cautious.

The difficulty in getting old vacant buildings back into use shows just how intractable the housing shortage is. Here are five Dublin buildings – some in public ownership, others private – whose stories illustrate the often achingly slow process of making old buildings habitable.

Podcast: Olivia Kelly on Dublin's empty houses

Last residents left in 1958

What a lovely residential road Blessington Street should be. The early-19th-century houses from its junction with Berkeley Street are, unusually, almost entirely intact. And this broad, tree-lined road leads to the old Royal Canal basin, which is now a pretty little park.

Unfortunately, though, Blessington Street has a face only a mother could love. Its houses are full of bedsits, with plenty of uPVC window frames and, bizarrely, some ceramic faux-brick covering real brickwork. The street has come down in the world since it was built, around 1810, mostly for members of the legal profession.

Of all the houses on the street number 28 has probably had the roughest time, having been used as a motorcycle-repair shop for 50 years, but it is this house that Daniel MacAuliff, along with his architect Caomhán Murphy, has chosen to turn back into a home.

“When Daniel bought it, in 2013, it had been vacant for quite a long time. There was water penetration at roof level, with trees growing out of it. The upper levels had been left abandoned because they were surplus to the commercial use,” Murphy says.

The house had been in residential use until 1958, when it was sold to Mountjoy Motorcycles. That company stayed until 2008. Then the building was bought by an investment company but left vacant. It slid into further dereliction before being bought by MacAuliff.

The building is one of only four so far that will benefit from the Living City Initiative, a tax-incentive scheme designed to encourage the renovation and reuse of pre-1915 properties.

Returning number 28 to residential use after so long as a commercial enterprise was a painstaking process that cost about €400,000. “It is a listed building, so there can be no short cuts,” Murphy says. Despite being unloved internally during its commercial years, the house still had two sash windows in the basement; wooden replicas have been made from them for the rest of the house.

The Living City Initiative could make a real impact in this part of Dublin, Murphy says. “Maybe we’re a bit ahead of ourselves, but, with the basin, with the proximity to town, I think this is an area that’s just waiting to happen.”

Work on the building was completed this year, and it will soon be available for residential use again, after almost 60 uninhabited years. It’s a rare positive outcome in this sector.

Could be derelict for many more years

Standing on North Frederick Street and looking down the hill towards Parnell Square and Abbey Presbyterian Church – aka Findlater’s Church – it’s just about possible to imagine the street in its Georgian glory. Laid out in 1780, and built over the following 20 or so years, it was an elegant series of mostly four-storey-over-basement homes.

The Georgian houses that survive are mostly occupied, but not number 30, which is a protected structure with a significant history. The house was bought in the late 19th century by Cathal McGarvey, who wrote the ballad Star of the County Down. He ran it as a guest house and social club, An Stad. (The sign was later moved to another building.) James Joyce, John MacBride, Oliver St John Gogarty, Michael Cusack and Michael Collins were recorded among its visitors.

The house has been empty for decades, during which time it has been sliding into dereliction. Last year Dublin City Council moved in to stabilise the building, after large sections of its back wall fell away. The council installed steel supports – none of the floors was safe, and the roof was no longer watertight – then sealed every window and door, and went away to determine what to do next. That was 20 months ago.

The council has removed the house from its derelict-sites register – which allows the council to fine owners who allow their property to fall into dereliction – on the basis that its intervention last year has rendered the building “nonderelict” – although you’d never guess from looking at it. And imposing fines would be pointless in terms of securing restoration of the house, the council says. Its owners are elderly, and one is a ward of court.

The council’s other option is to spend some of the €15 million in its new compulsory-purchase fund. The council is reluctant, however. It would take a long time and a lot of money to acquire, and, given its poor state of repair and protected status, it would be difficult to sell on.

There is no clear plan for the building, which could remain vacant and derelict for many more years.

Frawley’s, Thomas Street, Dublin 8

Housing for 244 students after lying vacant for 10 years

It may not have had the impact of the Clerys closure, but when Frawley’s department store, on Thomas Street, shut down in 2007, after 115 years, it was a blow to the Liberties area.

The developer Liam Carroll bought the shop and some surrounding buildings, reputedly for about €10 million, and set about plans to raze the lot. Although all but two of the buildings dated from the 18th century, he got permission in 2008 to demolish the row of six buildings centring on Frawley’s and to replace them with an office block.

During an appeal to An Bord Pleanála the plans were altered to retain the Thomas Street frontage of the historic buildings. But the economy crashed before Carroll could get busy with the wrecking ball, and his properties fell into the hands of Nama.

In 2013 Hattington Capital bought the buildings from receivership for about €2 million. The company sought and was granted an extension of Carroll’s planning permission, but in 2015 it applied for a new scheme. Earlier this year it was granted permission to refurbish the old buildings and build a new block at the rear, which together would provide accommodation for 244 students.

Most of the original internal features of the buildings had been stripped out years ago, according to John Harrington of Hattington Capital. “Conservation wasn’t high on the agenda back then.” It would, he says, be easier to level the lot and start again. “Dealing with a period building doesn’t make things easier, and it certainly doesn’t make things cheaper, but, ultimately, we think it will be worth it. People like living in refurbished period buildings.”

Thomas Street itself was a draw for the company, which it sees as a lively street attractive to students. It has a certain gritty charm, and a number of businesses have opened recently, but it also suffers from much dereliction, which the reuse of the Frawley’s terrace should go some way to addressing.

Work on the building began in recent weeks. When complete it will house more than 200 students after a decade of vacancy.

181-187 Townsend Street, Dublin 2

Tenants moving into 18 apartments in 2018

Despite being a stone’s throw from College Green, Townsend Street lives up to its name. Characterised by the back ends of buildings – and by some of the worst office blocks constructed in the city between the 1960s and the 1990s – the street gives the strong impression that the town has suddenly ended.

Just past the corner where Townsend Street meets Hawkins Street, near the back of Pearse Street Garda station and opposite the grim College House, a 100-year-old housing development lies empty. It’s not obvious, as shops remain open on the ground floor of the building, but its three upper floors of 18 flats have not had tenants for at least six years.

Built in about 1920 by Dublin Corporation – they were some of the earlier social housing in the city – the flats were in use continuously until the end of the century. They were some of the best-located flats in Dublin, right in the middle of town, and opposite the Theatre Royal (which was demolished in the 1960s to make way for Hawkins House).

By the later years of the 20th century they were showing their age, and problems with the roof and plumbing had developed. Around 2000 the council stopped allocating flats in the block and began moving its mostly elderly residents to new accommodation. The last resident left about six years ago.

The council never developed firm plans for the building, although it did consider selling to developers and using the money to fund other social housing in the area.

In 2015 the Peter McVerry Trust identified the vacant building as having potential for renewal as permanent housing for homeless adults. It plans to refurbish and enlarge the existing one-bedroom apartments and to build ground-floor extensions. The 18 final units will be allocated to couples and individuals.

The trust, which has commissioned Darmody Architecture to develop design proposals for building, has been given State funding of €1.7 million for the project. It hopes to seek planning permission early next year and start work in the autumn, so that tenants can move in in 2018.

Moss Street, Dublin 2

Council is “considering the building’s future”

Just down the road from Townsend Street another old corporation block hasn’t fared so well. The Moss Street flats, completed in 1917, were commissioned in response to conditions in tenement slums that were threatening not only the health but also the lives of the city’s poorest people. The low point of that crisis came in 1913, when the collapse of two houses on Church Street killed several tenants.

The Moss Street flats, along with identical blocks on Luke Street and Townsend Street, were among the earliest social housing constructed after the slum clearances.

The red-brick building has been derelict for more than a decade; the council decided it had to move tenants out of such poor conditions.

An independent building survey it commissioned in 2007 said the complex could be reused after a significant upgrade. No progress was made.

In 2013 the National Association of Building Co-operatives, or Nabco, said it would be willing to take on the refurbishment. Preliminary plans were drawn up that would see the flats retain their original facade; an extension to the rear would provide 30 new apartments for people on the council’s social-housing waiting list.

The cost of the work was estimated at €2.2 million. This turned out to be extremely optimistic: the flats had deteriorated significantly since the 2007 survey. The project appeared to have been shelved, but it reappeared last year with a budget of €5.5 million for 19 apartments, as part of a social-housing funding plan announced by Alan Kelly when he was minister for the environment.

Nabco, now renamed Co-operative Housing Ireland, had hoped to submit an application this year, but it says further assessment of the project is now needed. It still hopes to be involved, having secured the funding commitment.

The council says it is considering the future of the building in the context of surrounding vacant sites and their potential for redevelopment.

It is unclear if, or when, this building could play a role in alleviating Dublin’s chronic housing crisis.