diff --git a/plugins/ruby/building.rb b/plugins/ruby/building.rb
index d88bbfc69..0a48386c5 100644
--- a/plugins/ruby/building.rb
+++ b/plugins/ruby/building.rb
@@ -48,6 +48,7 @@ module DFHack
             bld.race = ui.race_id
             subtype = WorkshopType.int(subtype) if subtype.kind_of?(::Symbol) and type == :Workshop
             subtype = FurnaceType.int(subtype) if subtype.kind_of?(::Symbol) and type == :Furnace
+            subtype = CivzoneType.int(subtype) if subtype.kind_of?(::Symbol) and type == :Civzone
             bld.setSubtype(subtype)
             bld.setCustomType(custom)
             case type