A wall module for defining one or more individual work spaces within a building, the wall module comprising: an upper section having at least two first vertical supports (130a', 130a") and one or more first horizontal supports connected to at least one of the at least two first vertical supports (130a', 130a"), each of the first vertical supports (130a', 130a") of the at least two first vertical supports including a first channel therein; a lower section having at least two second vertical supports (130b', 130b") and one or more second horizontal supports connected to at least one of the at least two second vertical supports (130b', 130b"), each of the second vertical supports (130b', 130b") of the at least two second vertical supports (130b', 130b") including a second channel therein, the first and second channels being aligned with each other; a plurality of mounting supports (140', 140") connected to the lower section, the plurality of mounting supports including third channels aligned with the second channels; and one or more splines (190', 190") coupling the upper section to the lower section, the one or more splines (190', 190") being slidable within the first, second, and third channels, the slidable splines allowing the upper section to be decoupled from the lower section by removing the one or more splines (190', 190") from the first channel and positioning the one or more splines (190', 190") within one or more of the second and third channels ; characterized in that the at least two second vertical supports (130b', 130") include a left second vertical support (130b") and a right second vertical support ; and one horizontal support of the one or more second horizontal supports is rigidly connected to the left second vertical support, and movably connected to the right second vertical support. an upper section having at least two first vertical supports (130a', 130a") and one or more first horizontal supports connected to at least one of the at least two first vertical supports (130a', 130a"), each of the first vertical supports (130a', 130a") of the at least two first vertical supports including a first channel therein; a lower section having at least two second vertical supports (130b', 130b") and one or more second horizontal supports connected to at least one of the at least two second vertical supports (130b', 130b"), each of the second vertical supports (130b', 130b") of the at least two second vertical supports (130b', 130b") including a second channel therein, the first and second channels being aligned with each other; a plurality of mounting supports (140', 140") connected to the lower section, the plurality of mounting supports including third channels aligned with the second channels; and one or more splines (190', 190") coupling the upper section to the lower section, the one or more splines (190', 190") being slidable within the first, second, and third channels, the slidable splines allowing the upper section to be decoupled from the lower section by removing the one or more splines (190', 190") from the first channel and positioning the one or more splines (190', 190") within one or more of the second and third channels ; characterized in that the at least two second vertical supports (130b', 130") include a left second vertical support (130b") and a right second vertical support ; and one horizontal support of the one or more second horizontal supports is rigidly connected to the left second vertical support, and movably connected to the right second vertical support. <EOS>