Bought 4 of these Kibri kits on Ebay, will kitbash them to 1 large factory building.
The walls are made up of pieces like this.
Ground floor without changes.
Cut the coloms of both sides in the middle.
Also cut off one layer of the bottom ledger. Used a Proxxon mini table saw for this.
Left ground floor with the coloms cut.
Put the walls together, will have to fill up some gaps or disguise/hide them.
Pinted with Pollyscale Grimy Black and Dirt, then several washes of Artists Oil paint mixed with white spirit.
Close up of one of the deatils.