The blaze burned two bedrooms, Walker's shed, the garage and the carport. All contents of the house were ruined.
"I didn't have contents insurance. We couldn't afford it after we bought the house."
Rotorua Fire Station senior station officer Tony Kelly said when he and the fire crews arrived at the scene the fire was spreading from the garage to the house.
Kelly said it took firefighters 30 minutes to get the fire under control and another three hours to extinguish it completely.
"We stay as long as we can to make sure everything is completely out."
Kelly said Rotorua firefighters had been busy over the hot and dry summer, especially with structure fires in the city.
"A lot of the fires have come from overloaded plugs and sockets."
The Walker family are living with mother-of-four and neighbour Zoe McCartie while they get back on their feet. McCartie has also started a Givealittle page to raise funds for the family.
"It's definitely rocked their world," McCartie said.
McCartie has lived next to the Walker family for three years. McCartie and her children were at home when their neighbours' home went up in flames.
"I smelled some smoke and had a look outside but [didn't see anything] so I didn't think anything of it."
Then McCartie said she started to see the flames and called 111.
"By the time the firefighters got there the flames were leaping out the side of the building, one or two metres high.
"There were a few explosions. I thought the fire must have got to a gas bottle or something."
McCartie said she evacuated her family to another neighbour's house down the road while the fire was being put out.
Mamaku School principal Gary Veysi heard about the fire "straight away".
"We're a small community. There's lots of connections so news travels fast.
"Mamaku is quite an amazing place. When something like this happens everybody rallies around. People have offered [the family] clothing and you name it.
"In light of everything we've seen and the doom and gloom, we still have amazing people out there."
Veysi said one family had offered to buy school uniforms for Walker's 13-year-old son, a former Mamaku School student.
"He's a humble boy. A good citizen of the school who is kind and looks out for others."
Veysi said Walker's son played hockey well and hoped some of the funds raised by the Givealittle page could support his high school sporting goals.