diff --git a/backend/onboarders/epc_descriptions.py b/backend/onboarders/epc_descriptions.py
index 7f1d04e9..36e9a4f8 100644
--- a/backend/onboarders/epc_descriptions.py
+++ b/backend/onboarders/epc_descriptions.py
@@ -122,8 +122,8 @@ class EpcRoofDescriptions(Enum):
     # Loft
     # Assumed options
     pitched_insulated_assumed = "Pitched, insulated (assumed)"
-    # Known insulation at joists - we have 12, 25, 50, 75, 100, 125, 150, 175, 200, 225, 250, 270, 300, 350,
-    # 400+ as options
+    pitched_no_insulation = "Pitched, no insulation"
+    # Insulation thickness options
     loft_12mm_insulation: str = "Pitched, 12 mm loft insulation"
     loft_25mm_insulation: str = "Pitched, 25 mm loft insulation"
     loft_50mm_insulation: str = "Pitched, 50 mm loft insulation"
@@ -182,7 +182,7 @@ class EpcRoofDescriptions(Enum):
 
     # Sloping ceiling
     # For sloping ceiling tags, we don't use any (assumed) tags so that it's unambiguous that the roof is sloped
-    sloping_pitched_no_insulation: str = "Pithced, no insulation"
+    sloping_pitched_no_insulation: str = "Pitched, no insulation"
     sloping_pitched_limited_insulation: str = "Pitched, limited insulation"
     sloping_pitched_insulated: str = "Pitched, insulated"
 
@@ -372,6 +372,33 @@ def flat_insulated_efficiency(age_band: EpcConstructionAgeBand) -> EpcEfficiency
     pass
 
 
+def loft_insulated_efficiency(age_band: EpcConstructionAgeBand) -> EpcEfficiency:
+    """
+    2023 onwards -> Very Good
+    2012-2022 -> Very Good
+    2007-2011 -> Very Good
+    2003-2006 -> Very Good
+    1996-2002 -> Good
+    1991-1995 -> Good
+    1983-1990 -> Average
+    1976-1982 -> Average
+    1967-1975 -> Average
+    1950-1966 -> Average
+    1930-1949 -> Average
+    1900-1929 -> Average
+    before 1900 -> Average
+    :param age_band: Input age band, EpcConstructionAgeBand
+    :return: EpcEfficiency
+    """
+    year = age_band.start_year()
+    if year >= 2003:
+        return EpcEfficiency.VERY_GOOD
+    if year >= 1991:
+        return EpcEfficiency.GOOD
+
+    return EpcEfficiency.AVERAGE
+
+
 def flat_limited_efficiency(
     age_band: EpcConstructionAgeBand,
     insulation_thickness: int | None,
@@ -407,6 +434,7 @@ ROOF_DESCRIPTION_EFFICIENCIES: Mapping[EpcRoofDescriptions, RoofEfficiencyRule]
     EpcRoofDescriptions.flat_insulated: flat_insulated_efficiency,
 
     # Loft:
+    # value mappings
     EpcRoofDescriptions.loft_12mm_insulation: EpcEfficiency.VERY_POOR,
     EpcRoofDescriptions.loft_25mm_insulation: EpcEfficiency.POOR,
     EpcRoofDescriptions.loft_50mm_insulation: EpcEfficiency.POOR,
@@ -421,4 +449,8 @@ ROOF_DESCRIPTION_EFFICIENCIES: Mapping[EpcRoofDescriptions, RoofEfficiencyRule]
     EpcRoofDescriptions.loft_300mm_insulation: EpcEfficiency.VERY_GOOD,
     EpcRoofDescriptions.loft_350mm_insulation: EpcEfficiency.VERY_GOOD,
     EpcRoofDescriptions.loft_400mm_plus_insulation: EpcEfficiency.VERY_GOOD,
+    EpcRoofDescriptions.pitched_no_insulation: EpcEfficiency.VERY_POOR,
+    # function mappings
+    EpcRoofDescriptions.pitched_insulated_assumed: loft_insulated_efficiency,
+
 }
diff --git a/backend/onboarders/parity.py b/backend/onboarders/parity.py
index f7553617..c3b4184d 100644
--- a/backend/onboarders/parity.py
+++ b/backend/onboarders/parity.py
@@ -438,7 +438,6 @@ ROOF_UNKNOWN_AGE_FALLBACK = {
     "PitchedThatched": EpcRoofDescriptions.thatched_as_built_unknown,
     "PitchedNormalLoftAccess": EpcRoofDescriptions.loft_as_built_unknown,
     "PitchedNormalNoLoftAccess": EpcRoofDescriptions.loft_as_built_unknown,
-    
 }
 
 
@@ -454,9 +453,7 @@ def fill_roof_as_built(row):
         raise NotImplementedError(f"No roof classifier for roof type '{roof_type}'")
 
     if pd.isnull(row.construction_age_band):
-        raise NotImplementedError(
-            f"Missing age band for roof classification ({roof_type})"
-        )
+        return ROOF_UNKNOWN_AGE_FALLBACK.get(roof_type)
 
     output = classifier(row.construction_age_band)
     if output is None:
@@ -477,9 +474,12 @@ data["landlord_roof_description"] = data.progress_apply(
     fill_roof_as_built,
     axis=1,
 )
-
-for _, row in data.iterrows():
-    fill_roof_as_built(row)
+# Sanity check
+assert data["landlord_roof_description"].isnull().sum() == 0, (
+    "Some roof descriptions could not be resolved"
+)
+# TODO: 1) Map energy efficiency
+# TODO: 2) Flag sloped ceilings
 
 # Variables we want to map
 # 'Org Ref', 'Address 1', 'Address 2', 'Address 3', 'Postcode', 'Type',