Additions such as plastic boxes can be slotted inside the frames to store and display different items.
Sebton said that she aimed to design "one frame that could include different functions and still be a part of the decoration in the room."
Plastic boxes have been designed specifically to display plants and perforated iron boxes were created to hold magazines, books or brochures. Closed iron boxes can also be added for hiding contents away.
By fixing on an aluminium rail and hooks, the frame becomes an open clothes rack. An umbrella stand can also be clipped to the outside.
Sebton suggested that Add could be used to improve a workspace. She mentioned that the clothes on the rack could function as a sound absorber, while foliage might improve oxygen levels in the room.
Each frame sits on a circular cast-iron foot plate, with the option for a swivel version. The frames can be linked together to form room dividers or stand alone.
Available in two sizes, one wide and one narrow, the designs come powder-coated or finished in chrome.
Add was launched during Stockholm Design Week earlier this month, where Lammhults also presented sofas and armchairs that balance chunky upholstered seats on thin tubular steel frames.