In total, there were 18 firemen on site - eight used breathing apparatus - and four fire trucks.
Mr Blunt said the fire damaged the majority of the top floor, while the bottom floor received water damage.
He said firefighters could not go through the roof to dampen down the hot spots, because the "steep pitched roof was severely burnt" and they couldn't take the roof off because "there was not much structure left underneath".
A firefighter from Greerton station said there was no one inside the house when firefighters arrived.
Firefighters left the scene about 8pm.
Tauranga Fire Safety Officer Ken McKeagg was called to the scene to investigate the cause of the fire.