Brian Cairns, the owner of the property on Bede Burn Road in Jarrow, has said he has lost Â£50,000 worth of stock in the fire which started around 2am this morning.
An investigation is set to be launched later today following the blaze, which saw more than 40 firefighters and twelve appliances battling for hours to get the fire under control.
Some firefighters remain on scene to tackle the remaining hot spots, but now Mr Cairns is left waiting to see what will happen to the business he has invested more than Â£100,000 in over the last three years.
He said: "Everything is gone - there was Â£50,000 worth of stuff in the building - which is two storeys high and has a basement.
"There were furnishings and wood carvings, cast iron signs - which may still be there - and lots of brick-a-brac.
"At 2am this morning I got a call from one of my neighbours telling me that the rood was on fire, but by the time I got there there were a lot of appliances there and 40 plus firefighters.
"I stayed until 6am waiting for people to talk to us and then we just shot off and came back for 9am.
"I have been speaking to different customers to assure them we will pay for the stuff they have lost, as I have got to make sure everybody is paid.
"I have been in touch with the insurance company and an assessor is coming out to do a visit.
"It is down to them whether they decide to knock the building down or repair it.
"In the short term I am going to try and rent a warehouse for 12 months and to see we can get another location and try and keep on going."
And his determination has been met with overwhelming support from members of the public who have rallied round on social media offering to help raise money to keep the business going.
Mr Cairns added: "The public have been fantastic - I have had 400 to 500 messages on Facebook offering support and a couple of pages have been set up for people to donate."
Ten appliances and two special appliances were called to the fire around 2:30am today, with 44 firefighters spending hours bringing the fire under control.
The road was closed while emergency services worked however Northumbria Police has confirmed it has now reopened.
Thankfully no one was injured in the incident.
A statement on the Jarrow Auction Rooms Facebook page said: "Am gutted to say the least.
"Am devastated for the church as it is irreplaceable., but everybody is safe and well which is the important thing.
"We will be back."