diff --git a/backend/Property.py b/backend/Property.py
index c320fdd8..09c1d8ed 100644
--- a/backend/Property.py
+++ b/backend/Property.py
@@ -576,7 +576,7 @@ class Property:
                 "solid_floor_insulation", "suspended_floor_insulation",
                 "windows_glazing", "solar_pv", "heating", "hot_water_tank_insulation",
                 "heating_control", "secondary_heating", "cylinder_thermostat", "mixed_glazing",
-                "extension_cavity_wall_insulation", "mechanical_ventilation",
+                "extension_cavity_wall_insulation", "mechanical_ventilation", "sloping_ceiling_insulation"
             ]:
                 raise NotImplementedError(
                     "Implement me, given type %s" % recommendation["type"]