Building industry veteran Gerald Hoggard was only months away from moving into the St Georges Road property in the affluent suburb of Toorak when it was set alight.
Several neighbours called emergency services after noticing flames coming from the two-storey brick mansion on the corner of Ultimo Court just after midnight.
About 30 firefighters spent almost an hour battling the blaze from the outside, but it was completely destroyed by the inferno, according to Fire Rescue Victoria (FRV).
“The initial focus was on protecting the surrounding properties which were threatened by the heat and also by significant embers,” FRV commander Arran Dixon said.
“The crews have done a fantastic job.”
Hoggard is the founder of construction groups Extension Factory and Sperway Homes.
The house was undergoing renovation and nobody was home at the time, according to police.
Hoggard has spent the past three years building the property and was planning to move in with his family by Christmas. 
The building industry veteran told 9News he doesn’t believe it was a random attack, but does not know why his home would be deliberately targeted.
Arson chemists examined the charred remains of the mansion today, as FRV specialists and Victoria Police continue to investigate the cause of the fire.
The property was sold for more than $7 million in 2021, but renovations could have boosted its value to more than $15 million.
