Ths GGX (and also the similar GGZ) kits can be used to create a generic bus garage extension that can be adapted to your particular needs. Each kit will create a three sided square area of approximately 10" x 10", though you can reduce this if you wish, or you can add further kits.
The roof units can be left removable, but it is strongly suggested that the walls are permanently fixed to a base (MDF ?) to give strength to the structure.
The units can be used to extend another model in the range, or can be used to build a complex of your own design.
 
The GGX has a triplegable roof. It includes internal roof trusses and is available in red or yellow brick. The interior walls are finished in white brick with a black base.
In the photographs rooflight windows are shown. These are not included but may be made quite easily using clear plastic sheet and a frame from thin white card. The kit includes extra parts to enable extra exits in the side walls to be added if required.