Ms Trevanion, along with fellow antiques expert Aaron Dean, has given a new lease of life to the former J B Joyce and Co factory building on Station Road in Whitchurch.
For the last couple of months they have overseen the revamp of the building, which has seen it undergo a thorough clean, repairs to the roof and improvements to the reception area.
The pair, who reopened the building on Monday, are now preparing to host their first auction on Saturday, which will start at 11am.
A host of jobs have been created as a result of the venture, including five members of viewing staff and a receptionist.
Ms Trevanion, who has appeared on TV shows such as Antiques Road Trip, Bargain Hunt and Flog It, said she was excited about the project.
"We are really excited. It's been hard work but we are pleased with what we achieved so far, she said.
"It has been used as a factory so we have had to clear away more than 100 years of industrial grime. We have given it lots of TLC.
"We have also had to replace the ceilings, repair the roof and had a new internal staircase installed.
"The support from people has been phenomenal. I think people are happy with what we have done to the building."
Ms Trevanion said the pair were keen to preserve as much as the historic building as possible.
"It is a fantastic building. One of the main things that attracted us to the building was how light it is on the first floor. To have so much natural light is fantastic," she said.
"We want it to become very much a part of Whitchurch – a place which will be open for people to come and see us, where they will receive a warm welcome and where the kettle will always be on."
The building, which has been empty for about two years, dates back to the early 1900s when the building was built, owned and occupied by J B Joyce and Co.
Among the items to be auctioned at the first sale are jewellery, books, furniture and ornaments.
Mr Dean said the support the pair have received for the venture has been overwhelming.
"It has been nice to get people say how pleased they are with what we have done, wish us luck and ask can if they can look inside the building," he said.
"Our aim is to be a good, if not the best auction house around here.
"We want people to have fun and enjoy the experience. We also want the community to feel a part of it."
The building has undergone a through clean, while improvements have been made to the roof and reception area.
"We have to keep looking back at what it was like before we started to realise how much we have achieved and how far we have come," Mr Dean added.
Ms Trevanion said: "It is a lifetime project and there are still things we want to achieve."
The building was purchased last year and the pair were granted planning permission from Shropshire Council to transform it in October.
During public consultation, the council received 15 letters of support for the scheme and two against.
Those in support believe it will help preserve the "iconic" building and welcomed the creation of jobs.
But those against it fear it will increase the existing parking problems in the area.
Councillor Rob Hewson, mayor of Whitchurch, said: "I think it is a great idea and a great venture. It is another thing that will help put Whitchurch on the map.
"She is a lovely lady and anything I can help with, I am willing to do."
The building, which has been empty for two years, dates back to the early 1900s when the building was built, owned and occupied by J B Joyce and Co – one of the oldest continuous clock makers in the world.
The clock-making firm has been embedded in Shropshire history since 1690 when William Joyce began making long case clocks in Cockshutt. The family business was handed down from father to son and in 1790 moved to High Street, Whitchurch, before moving to Station Road in 1904.
Auctions will take place on February 14, March 14, May 9, June 13, July 11, August 8, September 12, October 10, November 7 and December 12.
People can view the auction in person on the Thursday before, from 9am to 7pm and on the Friday before, from 9am to 5pm.
A cafe serving light refreshments will also be available.
For more details visit www.trevanionanddean.co.uk or call (01948) 800202.