Instead of letting carts through, the 18th century Cotswold stone building will form a grand entrance to the Gloucestershire company's auctions, starting with their sporting sale on September 5.
Fortnightly auctions will continue to take place in a converted grain store at Norcote Farm, on the outskirts of Cirencester. But visitors will enter the building through those huge cart doors of the barn next door and the two buildings will be joined by a modern glazed walkway.
The barn has been converted to provide "extra accommodation for an expanding team, and a more welcoming environment for buyers and sellers", say the saleroom.
Mr Allwood said: "When we came to Norcote in 1999 we had three full-time members of staff. Now we have seven people here full time and as many part time. The availability of the stone barn gave us the opportunity to provide extra office accommodation for our team, a welcoming new reception away from the hustle-bustle of the saleroom, and private spaces where we can offer valuations."