It will be one of Australia's most compelling dining venues when completed and offer some of the best views of Perth.
But right now, it is a logistical puzzle for the minds behind the Old Treasury Building redevelopment to solve.
A 470sqm glass box, which will eventually be fitted out as restaurant that can seat 100, will need to be transported from Maddington, where it sits in storage, and hoisted on to the roof of the St Georges Terrace property.
Kyle Jeavons, project senior development manager at FJM Property, said it would be a "tremendous" task, with little room for error and could take days to complete.
But the one-of-a-kind space will no doubt be worth all the trouble when it opens amid the city towers in April next year.
Mr Jeavons said the rooftop restaurant, among eight food and drink venues planned at the site, would not only offer views of the Swan River and surrounds but also allow patrons to appreciate fully some of the painstaking work undertaken to restore the 135-year-old building.
One of the biggest restoration works has been reinstating the slate and copper roof.
More than 60,000 pieces of Welsh slate were imported for the task and nailed in, piece by piece, over six months.
Mr Jeavons said the rooftop restaurant was an idea pushed by the project's construction manager, Chris Holdich from Built.
Mr Holdich was the project manager on the redevelopment of the highly acclaimed White Cube Gallery in Hoxton, London, where a similar structure was installed. "We are fortunate to have his expertise - he has been the champion of this project," Mr Jeavons said. "There was also a modular restaurant on top of the Le Palais De Tokyo in Paris, which was quite similar to ours, however, this only catered for 12 people.
"The Treasury project is lucky enough to have some incredibly interesting and intriguing spaces … the rooftop space will certainly be one of the most exciting due to the views and experiences it will afford."
The Old Treasury Building, the heart of the $584 million Treasury-Cathedral precinct, will be transformed into a premier hospitality centre, with restaurants, bars, shops and an exclusive hotel.