The developer of the former Pavilion Market site — which has been the focus of a heritage-versus-density debate — claims he is saving Subiaco’s old streets.

A 24-storey tower in the $280 million development, which is believed to be the most expensive apartment project ever in WA, has been subject to some of the western suburbs’ well-publicised resistance to density.

While critics say the tall building will destroy the village and heritage atmosphere, and potentially damage heritage homes during construction, Paul Blackburne said it was a case of density done right.

“Density’s got to happen anyway, right? The way you save the backstreets, and you save Subi, is to put the height in the right locations,” he said.

“It’s about putting density in the right spots, and then not being too worried about exactly how high it is.

“We actually realised when we bought the site that we are going to be the ones to save the heritage, character backstreets of Subi because if you don’t put height in spots like this, in the town centre, then the population growth is going to go further out, into the backstreets.”

The words may well rankle the owners of heritage terrace homes on nearby Catherine Street, who fear the construction work will destroy their houses.

The Development Assessment Panel, which approved the project, noted the potential for damage, and ordered dilapidation reports for the homes.

But the reports are reportedly flawed, and have exposed local heritage laws as too weak to protect even the Sistine Chapel from neighbouring excavation and vibrations.

No doubt all eyes will be on the project to consider the extent to which Mr Blackburne helps save — or damage — Subiaco’s heritage. Known as One Subiaco, the project is extreme in every sense. It is WA’s most expensive complex, with the most costly penthouse, built on one the Perth’s most iconic sites, and is one of the State’s most controversial developments yet.

With 1000 pre-registrations before the sales campaign has started, it may also prove to be one of the most popular developments too. Which is why it is so astounding that it is not being done by a billion-dollar publicly listed company, but by a 43-year old local developer.

Mr Blackburne said his approach to apartments has been shaped by living in them.

“I have lived in apartments most of the past 20 years and was so often disappointed with average design quality and high prices,” he said.

He said the previous planned 16-storey tower with 299 apartments, which he inherited when he bought it a year ago, would have created similarly small and overpriced apartments. Mr Blackburne said he could not make the sums work on the inherited design.

First, the design included 70 apartments without a car bay, which he said would have been difficult to sell in WA, holding up construction and reducing the annual return on equity.

“The project could not proceed unless we have all apartments with two bays, and mostly side by side,” he said. He had the apartment complex redesigned to add an extra eight storeys to one building.

With the expansive views on the upper levels set to sell at a higher sale price, the lower-level apartments became cheaper and easier to sell, and the project was suddenly viable.

The new design was approved by the Joint DAP with 24 public responses, 16 in favour and eight against.

Interestingly, in the redesign — approved three months ago — the number of apartments fell from 299 to 242.

Mr Blackburne concedes it is still a sizeable number of apartments, and claims the economies of scale were key in feeding into the affordability of the apartments, by reducing the individual share of the costs for common areas (such as the rooftop resort) across a substantial number of owners.

He said the redesign moved the Seddon tower from a shorter, fatter building to a taller, more slender one, allowing a greater amount of natural light.

Speaking ahead of the public launch next month, Mr Blackburne revealed details of the three buildings in ONE Subiaco — called Rokeby, Roberts and Seddon — explaining apartments will range in size from one to six bedrooms.

The Rokeby building on the corner of Rokeby and Roberts Road will have 22 residences, and the Roberts building will include 90 apartments. The Seddon building has 125 residences with views from Rottnest to Fremantle, Kings Park and the Perth Hills.

Mr Blackburne said he had four expressions of interest for the penthouses, including a full floor for $17 million, with one potential buyer discussing a double penthouse for about $43 million.

The hefty price tag has raised eyebrows, with some amused the penthouse could seek more than the asking price on The Towers, at Elizabeth Quay, which is on the market for $12.8 million. Time will tell if Mr Blackburne is a visionary or a dreamer.