diff --git a/backend/onboarders/parity.py b/backend/onboarders/parity.py
index cb9b4f7f..f2f940ba 100644
--- a/backend/onboarders/parity.py
+++ b/backend/onboarders/parity.py
@@ -296,13 +296,6 @@ roof_aggs = data[["Roof Construction", "Roof Insulation"]].drop_duplicates().to_
     # Thatched
 
     # Sloping
-    {'Roof Construction': 'PitchedWithSlopingCeiling', 'Roof Insulation': 'AsBuilt'},
-    {'Roof Construction': 'PitchedWithSlopingCeiling', 'Roof Insulation': 'mm150'},
-    {'Roof Construction': 'PitchedWithSlopingCeiling', 'Roof Insulation': 'mm100'},
-    {'Roof Construction': 'PitchedWithSlopingCeiling', 'Roof Insulation': nan},
-    {'Roof Construction': 'PitchedWithSlopingCeiling', 'Roof Insulation': 'mm50'},
-    {'Roof Construction': 'PitchedWithSlopingCeiling', 'Roof Insulation': 'NoInsulation'},
-    {'Roof Construction': 'PitchedWithSlopingCeiling', 'Roof Insulation': 'Unknown'},
 
     # Sloping ceiling:
     # With measured insulation
@@ -391,6 +384,25 @@ roof_mapping = {
     ('PitchedThatched', 'mm300'): EpcRoofDescriptions.thatched_with_additional_insulation,
     ('PitchedThatched', 'Unknown'): EpcRoofDescriptions.thatched,  # efficiency classified based on age
 
+    # Sloping:
+    # Limited (12 very poor, 25-50 poor)
+    ('PitchedWithSlopingCeiling', 'mm12'): EpcRoofDescriptions.sloping_pitched_limited_insulation,
+    ('PitchedWithSlopingCeiling', 'mm25'): EpcRoofDescriptions.sloping_pitched_limited_insulation,
+    ('PitchedWithSlopingCeiling', 'mm50'): EpcRoofDescriptions.sloping_pitched_limited_insulation,
+    # Insulated 75mm+ (75 - 125 average, 150 - 250 good, 270+ very good)
+    ('PitchedWithSlopingCeiling', 'mm75'): EpcRoofDescriptions.sloping_pitched_insulated,
+    ('PitchedWithSlopingCeiling', 'mm100'): EpcRoofDescriptions.sloping_pitched_insulated,
+    ('PitchedWithSlopingCeiling', 'mm150'): EpcRoofDescriptions.sloping_pitched_insulated,
+    ('PitchedWithSlopingCeiling', 'mm200'): EpcRoofDescriptions.sloping_pitched_insulated,
+    ('PitchedWithSlopingCeiling', 'mm250'): EpcRoofDescriptions.sloping_pitched_insulated,
+    ('PitchedWithSlopingCeiling', 'mm270'): EpcRoofDescriptions.sloping_pitched_insulated,
+    ('PitchedWithSlopingCeiling', 'mm300'): EpcRoofDescriptions.sloping_pitched_insulated,
+    ('PitchedWithSlopingCeiling', 'mm350'): EpcRoofDescriptions.sloping_pitched_insulated,
+    ('PitchedWithSlopingCeiling', 'mm400'): EpcRoofDescriptions.sloping_pitched_insulated,
+    # As built/unknown
+    ('PitchedWithSlopingCeiling', 'AsBuilt'): None,  # To be classified
+    ('PitchedWithSlopingCeiling', nan): None,  # To be classified
+    ('PitchedWithSlopingCeiling', 'Unknown'): None,  #
 }
 
 
@@ -404,6 +416,8 @@ def classify_flat_roof(age_band: EpcConstructionAgeBand) -> EpcRoofDescriptions:
     1976–1982                  → Flat, limited insulation
     1967–1975                  → Flat, limited insulation
     1950–1966 and earlier      → Flat, no insulation
+    :param age_band: Input age band
+    :return: EpcRoofDescriptions
     """
 
     year = age_band.start_year()
@@ -417,17 +431,31 @@ def classify_flat_roof(age_band: EpcConstructionAgeBand) -> EpcRoofDescriptions:
     return EpcRoofDescriptions.flat_no_insulation
 
 
-def classify_thatched_roof(age_band: EpcConstructionAgeBand):
-    raise NotImplementedError("Thatched roof classification not implemented yet")
+def classify_sloping_ceiling_roof(age_band: EpcConstructionAgeBand) -> EpcRoofDescriptions:
+    """
+    For a sloping ceiling, as built roof, these are the breakdowns:
+    2023 onwards               → Sloping pitched, insulated
+    2003–2022                  → Sloping pitched, insulated
+    1983–2002                  → Sloping pitched, insulated
+    1976–1982                  → Sloping pitched, limited insulation
+    1967–1975 and earlier      → Sloping pitched, no insulation
+    :param age_band: Input age band
+    :return: EpcRoofDescriptions
+    """
+    year = age_band.start_year()
 
+    if year >= 1983:
+        return EpcRoofDescriptions.sloping_pitched_insulated
 
-def classify_sloping_ceiling_roof(age_band: EpcConstructionAgeBand):
-    raise NotImplementedError("Sloping ceiling roof classification not implemented yet")
+    if year >= 1976:
+        return EpcRoofDescriptions.sloping_pitched_limited_insulation
+
+    return EpcRoofDescriptions.sloping_pitched_no_insulation
 
 
 AS_BUILT_ROOF_CLASSIFIERS = {
+    # Only need to apply this to flat and sloping ceiling roofs
     "Flat": classify_flat_roof,
-    "PitchedThatched": classify_thatched_roof,
     "PitchedWithSlopingCeiling": classify_sloping_ceiling_roof,
 }