The old Raupunga store burnt to the ground on Thursday morning.
Wairoa chief fire officer Grant Duley said they were called to property at seven minutes past midnight but by the time they arrived the house was completely gone.
"I arrived 10 minutes after the first crew and the house, which use to be the old dairy, no longer existed."
He said the fire appeared to have started in one of the bedrooms but everyone got out safely.
"The young fella who was in the house woke to smoke and got his grandmother out."
Mr Duley said they received multiple calls that the old garage next to the house had also caught fire but luckily there was a concrete barrier between the two.
"It started to get into the eaves of the old garage but it did not catch alight."
Mr Duley said firefighters spent about three hours dampening down the remains of the house.
"All that was left was a tin. It was a shame it was such a hot fire."
Police attended and carried out an inquiry into the cause of the fire.
Mr Duley said police spoke to the young boy who had escaped the fire but found nothing suspicious.
This is the second tragedy to hit the area in two days after the shooting on Wednesday.
A man has been charged with the murder of his son Blair Philip Herbert Cole and appeared in the Gisborne District Court Thursday morning. He was remanded in custody.