The Crown Inn, West Street, will shut at midnight on Sunday, December 1, and reopen fully on Wednesday, December 11.
The revamp includes a new carpet, furniture, and upgraded bar equipment.
The kitchen will also get a complete overhaul, featuring a new walk-in fridge-freezer.
A new staff room and toilet facilities are also being added.
Pub manager Lucy Dempsey said: “The £300,000 investment highlights Wetherspoon’s commitment to the pub and its staff and customers, as well as to the local area itself.
“Myself and my team are looking forward to welcoming customers back into The Crown Inn and also welcome the upgraded pub facilities.”
The pub, which opened as a Wetherspoon in March 2009, will see its kitchen close earlier at 6pm on Sunday, December 1.
