It is unknown what caused the incidents.
Donations and offers of help have flooded in for Bruce and Jocelyn Buchanan and their two young grandsons, 9-year-old William and 10-year-old Hunter.
A Givealittle page set up for the family had raised more than $1500 by last night. Hawke's Bay Today also received a donation of $50 for the family.
Family friend Karen Watson said a working bee had been set up yesterday, with several people lending a helping hand to empty the family's garage and make it suitable to sleep in.
The story of the Buchanans' plight had been shared on Facebook and, within an hour, their dining table was "chocka" with clothes, Watson said.
"I've had all sorts of people come to my door who don't know the family but want to help. It's amazing what people can do."
William has cerebral palsy and recently had an operation which meant he had casts on both legs and was wheelchair-bound. Unfortunately, his wheelchair and Bruce's wheelchair were destroyed in the fire.
To donate money to the Buchanan family, visit: https://givealittle.co.nz/cause/help-for-the-buchanan-family-after-fire-destroys