Crews responded to the fire shortly after 3 a.m.
When crews arrived on scene, they found heavy smoke filling the building.
Firefighters entered the building from the front and called for reinforcements. They found the fire in the back of the building near the loading dock.
Fire investigator Rob Garrison said the fire started somewhere in the vinyl or foam lining of the loading dock pad.
Garrison said a triggered sprinkler head helped keep the fire contained before crews arrived.
The fire damage was confined to the back wall, the area where trucks load and unload, and a truck that was backed up to the door at the time of the fire.
No one was injured and no one was inside the building when the fire started.
Garrison is still investigating the cause of the fire.
The store is closed until further notice.