Compound fenestration assembly mull joints, compound fenestration assemblies using those mull joints, and methods of making and using the same are described herein. The mull joints in compound fenestration assemblies as described herein use universal joining strips to form both sides of a mull joint, as well as other universal components such as, e.g., corner gussets, locator plates, end plugs, seal members, etc. that may be used as needed to form mull joints as required in a compound fenestration assembly.

An exemplary demountable barrier system includes a panel, a frame structure having a channel to receive the panel, and a seal compressing against the panel to hold the panel. The seal is slideably attached to the frame structure.

Window lite assemblies and methods for installing the assemblies are provided herein. The assemblies described herein are configured to be installed in new and existing buildings, especially in building corners, while leaving some or all of the horizontal structural members such as headers and sills in place.