Both fuel pumps and the 24-hour Londis store are closed entirely until Saturday and after that the shop remains out of action until Monday, March 25.
The works are part of an extension to the forecourt building to include a 24-seat Subway sandwich shop, due to open this spring.
The existing plant room is also being demolished and replaced with a storage building and new access provided directly to the Subway at the east end of the garage.
A Shell spokeswoman said: “Shell Jedburgh is planned to be fully closed from March 4 to 9, for redevelopment. The service station will be fuel only from March 9 to 25, until the works are fully completed.”
“We are always looking to improve our service stations to provide our customers with the best quality of service and offering.”