diff --git a/hub/city_model_structure/building.py b/hub/city_model_structure/building.py
index b3d45617..a5650013 100644
--- a/hub/city_model_structure/building.py
+++ b/hub/city_model_structure/building.py
@@ -262,8 +262,8 @@ class Building(CityObject):
   @property
   def usages(self) -> Union[None, list]:
     """
-    Get building function
-    :return: None or str
+    Get building usages, if none, assume useage is function
+    :return: None or list of functions
     """
     if self._usages is None and self._function is not None:
       self._usages = [{'usage': self._function, 'ratio': 1 }]
@@ -604,19 +604,6 @@ class Building(CityObject):
     """
     self._city = value
 
-  @property
-  def usages_percentage(self):
-    """
-    Get the usages and percentages for the building
-    """
-    _usage = ''
-    for internal_zone in self.internal_zones:
-      if internal_zone.usages is None:
-        continue
-      for usage in internal_zone.usages:
-        _usage = f'{_usage}{usage.name}_{usage.percentage} '
-    return _usage.rstrip()
-
   @property
   def energy_systems(self) -> Union[None, List[EnergySystem]]:
     """
diff --git a/hub/imports/usage/comnet_usage_parameters.py b/hub/imports/usage/comnet_usage_parameters.py
index adf65aed..343bd3df 100644
--- a/hub/imports/usage/comnet_usage_parameters.py
+++ b/hub/imports/usage/comnet_usage_parameters.py
@@ -78,7 +78,12 @@ class ComnetUsageParameters:
             logging.error('Building %s no number of storeys assigned, ACH cannot be calculated for usage %s. '
                           'NRCAN construction data for the year %s is used to calculated number of storeys above '
                           'ground', building.name,  usages, building.year_of_construction)
-            storeys_above_ground = self.average_storey_height_calculator(self._city, building)
+            try:
+              storeys_above_ground = self.average_storey_height_calculator(self._city, building)
+            except ValueError as e:
+              logging.error(e)
+              continue
+
           volume_per_area = building.volume / building.floor_area / storeys_above_ground
           for j, usage_type in enumerate(usages):
             usage = Usage()
@@ -90,6 +95,7 @@ class ComnetUsageParameters:
             internal_zone_usages.append(usage)
 
         internal_zone.usages = internal_zone_usages
+
   @staticmethod
   def _search_archetypes(comnet_catalog, usage_name):
     comnet_archetypes = comnet_catalog.entries('archetypes').usages
@@ -268,7 +274,7 @@ class ComnetUsageParameters:
     nrcan_catalog = ConstructionCatalogFactory('nrcan').catalog
 
     if building.function not in Dictionaries().hub_function_to_nrcan_construction_function:
-      logging.error('Building %s has an unknown building function %s', building.name, building.function)
+      raise ValueError('Building %s has an unknown building function %s', building.name, building.function)
 
     function = Dictionaries().hub_function_to_nrcan_construction_function[building.function]
     construction_archetype = None
@@ -281,7 +287,7 @@ class ComnetUsageParameters:
           construction_archetype = building_archetype
           average_storey_height = building_archetype.average_storey_height
     if construction_archetype is None:
-      logging.error('Building %s has unknown construction archetype for building function: %s '
+      raise ValueError('Building %s has unknown construction archetype for building function: %s '
                     '[%s], building year of construction: %s and climate zone %s', building.name, function,
                     building.function, building.year_of_construction, climate_zone)
 
diff --git a/hub/imports/usage/nrcan_usage_parameters.py b/hub/imports/usage/nrcan_usage_parameters.py
index f9cf5e63..a6825bbc 100644
--- a/hub/imports/usage/nrcan_usage_parameters.py
+++ b/hub/imports/usage/nrcan_usage_parameters.py
@@ -86,8 +86,12 @@ class NrcanUsageParameters:
             logging.error('Building %s no number of storeys assigned, ACH cannot be calculated for function %s. '
                           'NRCAN construction data for the year %s is used to calculated number of storeys above '
                           'ground', building.name,  building.function, building.year_of_construction)
-            storeys_above_ground = self.average_storey_height_calculator(self._city, building)
-            continue
+            try:
+              storeys_above_ground = self.average_storey_height_calculator(self._city, building)
+            except ValueError as e:
+              logging.error(e)
+              continue
+
           volume_per_area = building.volume / building.floor_area / storeys_above_ground
           for j, usage_type in enumerate(usages):
             usage = Usage()
@@ -224,7 +228,7 @@ class NrcanUsageParameters:
     nrcan_catalog = ConstructionCatalogFactory('nrcan').catalog
 
     if building.function not in Dictionaries().hub_function_to_nrcan_construction_function:
-      logging.error('Building %s has an unknown building function %s', building.name, building.function)
+      raise ValueError('Building %s has an unknown building function %s', building.name, building.function)
 
     function = Dictionaries().hub_function_to_nrcan_construction_function[building.function]
     construction_archetype = None
@@ -237,7 +241,7 @@ class NrcanUsageParameters:
           construction_archetype = building_archetype
           average_storey_height = building_archetype.average_storey_height
     if construction_archetype is None:
-      logging.error('Building %s has unknown construction archetype for building function: %s '
+      raise ValueError('Building %s has unknown construction archetype for building function: %s '
                     '[%s], building year of construction: %s and climate zone %s', building.name, function,
                     building.function, building.year_of_construction, climate_zone)