diff --git a/city_model_structure/building_demand/material.py b/city_model_structure/building_demand/material.py
index fa5033d3..3cd22965 100644
--- a/city_model_structure/building_demand/material.py
+++ b/city_model_structure/building_demand/material.py
@@ -12,8 +12,9 @@ class Material:
   """
   Material class
   """
-  def __init__(self, type, material_id, material_name, density, density_unit, embodied_carbon, embodied_carbon_unit, recycling_ratio,
-               onsite_recycling_ratio, company_recycling_ratio, landfilling_ratio, cost, cost_unit):
+  def __init__(self, type=None, material_id=None, material_name=None, density=None, density_unit=None,
+               embodied_carbon=None, embodied_carbon_unit=None, recycling_ratio=None, onsite_recycling_ratio=None,
+               company_recycling_ratio=None, landfilling_ratio=None, cost=None, cost_unit=None):
     self._type = type
     self._id = material_id
     self._name = material_name