diff --git a/datatypes/epc/domain/mapper.py b/datatypes/epc/domain/mapper.py
index 10ec411d..ed91551d 100644
--- a/datatypes/epc/domain/mapper.py
+++ b/datatypes/epc/domain/mapper.py
@@ -1568,8 +1568,14 @@ class EpcPropertyDataMapper:
                         else None
                     ),
                 )
+                # RdSAP 10 §6.1 — exclude the glazed conservatory BP from the
+                # fabric loop; it is carried as `sap_conservatory` below and
+                # billed by the §6.1 cascade (window/rooflight/floor), not as
+                # a dwelling building part. Mirrors the 21.0.1 path.
                 for bp in schema.sap_building_parts
+                if getattr(bp, "glazed_perimeter", None) is None
             ],
+            sap_conservatory=_api_sap_conservatory(schema.sap_building_parts),
         )
 
     @staticmethod
diff --git a/datatypes/epc/domain/tests/test_from_rdsap_schema.py b/datatypes/epc/domain/tests/test_from_rdsap_schema.py
index a2463eae..070b100c 100644
--- a/datatypes/epc/domain/tests/test_from_rdsap_schema.py
+++ b/datatypes/epc/domain/tests/test_from_rdsap_schema.py
@@ -2433,3 +2433,76 @@ class TestNonSeparatedConservatoryApiMirror:
         # Assert — §6.2: disregarded; no conservatory geometry.
         assert epc.sap_conservatory is None
         assert conservatory_geometry(epc) is None
+
+
+class TestNonSeparatedConservatoryApiMirror19_0:
+    """RdSAP 10 §6.1 — the same glazed-BP conservatory the 21.0.1 mapper
+    handles is also lodged on RdSAP-Schema-19.0 (repro cert 718138). The four
+    glazed fields were undeclared on the 19.0 `SapBuildingPart`, so `from_dict`
+    dropped them: the conservatory mapped to a fabric-less building part that
+    mis-scored and could not persist (NOT-NULL `construction_age_band`). The
+    19.0 mapper now mirrors the 21.0.1 split.
+
+    Unlike 21.0.1, the 19.0 mapper keeps the **lodged** `total_floor_area`
+    scalar (a real 19.0 cert already lodges the non-separated conservatory in
+    it — 718138: dwelling 140.23 + conservatory 9.71 = 149.94 → lodged 150), so
+    appending a conservatory does NOT change `total_floor_area_m2`. The §6.1
+    floor-area fold reaches the score through the calculator's dimensions, not
+    through the scalar."""
+
+    def test_from_api_response_splits_out_conservatory_building_part(
+        self,
+    ) -> None:
+        # Arrange — the 19.0 dwelling plus a non-separated double-glazed
+        # conservatory glazed BP.
+        from datatypes.epc.domain.epc_property_data import SapConservatory
+        from domain.sap10_calculator.worksheet.conservatory import (
+            conservatory_geometry,
+        )
+
+        dwelling_part_count = len(
+            EpcPropertyDataMapper.from_api_response(load("19_0.json")).sap_building_parts
+        )
+
+        cert = load("19_0.json")
+        cert["conservatory_type"] = 4
+        cert["sap_building_parts"].append(
+            {
+                "floor_area": 12.0,
+                "room_height": 1,
+                "double_glazed": "Y",
+                "glazed_perimeter": 9.0,
+            }
+        )
+
+        # Act
+        epc = EpcPropertyDataMapper.from_api_response(cert)
+
+        # Assert — conservatory split out; the glazed BP is NOT a fabric part.
+        assert epc.sap_conservatory == SapConservatory(
+            floor_area_m2=12.0,
+            glazed_perimeter_m=9.0,
+            double_glazed=True,
+            thermally_separated=False,
+            room_height_storeys=1.0,
+        )
+        assert len(epc.sap_building_parts) == dwelling_part_count
+        # §6.1 fold is active (surfaces derived by the shared cascade).
+        assert conservatory_geometry(epc) is not None
+
+    def test_separated_conservatory_lodges_no_glazed_building_part(self) -> None:
+        # Arrange — a separated conservatory (type 2/3) lodges NO glazed BP;
+        # the dwelling is unchanged.
+        from domain.sap10_calculator.worksheet.conservatory import (
+            conservatory_geometry,
+        )
+
+        cert = load("19_0.json")
+        cert["conservatory_type"] = 2
+
+        # Act
+        epc = EpcPropertyDataMapper.from_api_response(cert)
+
+        # Assert — §6.2: disregarded; no conservatory geometry.
+        assert epc.sap_conservatory is None
+        assert conservatory_geometry(epc) is None
diff --git a/datatypes/epc/schema/rdsap_schema_19_0.py b/datatypes/epc/schema/rdsap_schema_19_0.py
index b91dff35..2ba0f3cb 100644
--- a/datatypes/epc/schema/rdsap_schema_19_0.py
+++ b/datatypes/epc/schema/rdsap_schema_19_0.py
@@ -122,6 +122,16 @@ class SapBuildingPart:
     wall_insulation_thickness: Optional[str] = None
     floor_insulation_thickness: Optional[str] = None
     flat_roof_insulation_thickness: Optional[Union[str, int]] = None
+    # RdSAP 10 §6.1 — a NON-SEPARATED conservatory (`conservatory_type == 4`) is
+    # lodged by the gov API as a glazed "building part" carrying ONLY these four
+    # fields (no fabric, no floor dimensions). Previously undeclared → dropped by
+    # `from_dict`, so the conservatory was silently lost on the 19.0 path. The
+    # mapper splits this BP out into `EpcPropertyData.sap_conservatory`. Mirrors
+    # the 21.0.1 schema declaration.
+    floor_area: Optional[Union[Measurement, int, float]] = None
+    room_height: Optional[Union[Measurement, int, float]] = None
+    double_glazed: Optional[str] = None
+    glazed_perimeter: Optional[Union[Measurement, int, float]] = None
 
 
 @dataclass