The new structure, with a total floorspace of 42 square metres, was placed on the grounds of the The Body Barn, in Church Aston, earlier this year.
A retrospective planning application submitted by company director and personal trainer Danny Robb last month said it provided space for “personal training, refreshments, sign-in and storage”.
Telford and Wrekin Council granted permission for the containers and a further proposed extension on the north side of its main gym building, a converted former farm building.
Blueprints submitted to the council show the new building, off Moorfield Lane, to the north of the main gym, is formed from three metal containers arranged in a T shape.
It consists of an open-plan waiting area and refreshments shop, with separate closed-off rooms for storage and personal training.
In application documents, Mr Robb added that, in addition to the retrospective approval for the shipping containers, “permission is sought for a proposed small extension to the existing main barn to provide additional sheltered workout space to enable fitness classes to continue with greater social distancing”.
He also noted that the work to construct the annexe began in February.
Plans show this is proposed for the northeast side of the building with a floorspace of 59.5 square metres, extending its size by a fifth.
Parts of the new annexe have been clad in timber, and, application documents say, the same will be done to the barn extension