The blaze caused an estimated $12 million damage when it enveloped Fiesta Foods on Finlay Place about 10.20am on August 22.
Michael Sikaloski, who owns the building and the land, described the incident as shocking and devastating.
�I�ve been at the game since I was 17,� he said. �To see it go in a couple of hours was just a very numbing experience.
�We�re devastated, but what can you do? At the end of the day you�ve got to pick yourself up and carry on.�
Mr Sikaloski was inside the building when a flue system caught fire, sending flames to the ceiling.
He said a fire crew arrived but a truck equipped with a boom was needed to reach the roof.
By the time that unit arrived it was too late.
Mr Sikaloski emphasised he did not blame the fire service, saying �it was just one of those things�.
He explained the building was not insured because insurance companies refused to cover it.
He said they thought cooling panels he used for the business to meet food safety regulations were too much of a fire risk.
But Mr Sikaloski considered it fire safe.
�You�ve got safety switches and all sorts of contraptions that safeguard from fire catching on� I don�t know what happened,� he said.
�We demolish and start again; I don�t want to give up 30 years of my hard work.
�As hard as it is to get back into it, I�ve just got to do it.�
He was overwhelmed by the support he had received from the community, including fire crews and the City of Wanneroo.
�It�s kept me going, I�ve had so many well wishes,� he said.
�So many customers have vowed to keep (us) open.
�The local church next to us have been fabulous.
�I can�t thank people enough.�
Firefighters were monitoring the collapsed building for hot spots until Tuesday.
Two fire trucks with aerial apparatus and more than 80 firefighters from 13 stations were needed to control the blaze.
A Department of Fire and Emergency Services spokesman said children from a nearby performing arts centre and people inside a funeral parlour were among those evacuated as toxic smoke billowed from the structure.