diff --git a/datatypes/epc/domain/mapper.py b/datatypes/epc/domain/mapper.py
index 24ee6d65e..3539fd0eb 100644
--- a/datatypes/epc/domain/mapper.py
+++ b/datatypes/epc/domain/mapper.py
@@ -738,6 +738,13 @@ class EpcPropertyDataMapper:
             # fires trigger (a) (sap_version < 10.2 → Effective = the SAP-10.2
             # calc) instead of keeping the lodged SAP-2012 score (ADR-0037).
             sap_version=schema.sap_version,
+            # gov property_type code → str, mirroring from_rdsap_schema_17_1.
+            # Feeds the calculator's house/flat heat-transmission split.
+            property_type=(
+                str(schema.property_type)
+                if schema.property_type is not None
+                else None
+            ),
             dwelling_type=(
                 schema.dwelling_type
                 if isinstance(schema.dwelling_type, str)
diff --git a/datatypes/epc/schema/sap_schema_17_1.py b/datatypes/epc/schema/sap_schema_17_1.py
index cbd58d72a..ab4a33fa3 100644
--- a/datatypes/epc/schema/sap_schema_17_1.py
+++ b/datatypes/epc/schema/sap_schema_17_1.py
@@ -202,6 +202,10 @@ class SapSchema17_1:
     # Drives Rebaselining trigger (a): sap_version < 10.2 → Effective = the
     # SAP-10.2 calc, not the lodged figure (ADR-0037). Optional defensively.
     sap_version: Optional[float] = None
+    # gov property_type code (0 house, 1 bungalow, 2 flat, 3 maisonette, 4 park
+    # home). Feeds the calculator's house/flat heat-transmission split; left
+    # absent the dwelling is classified as neither → mis-scored (ADR-0037).
+    property_type: Optional[int] = None
     # measured living-room area (m²); the engine consumes it via a back-solved
     # habitable_rooms_count (Table 27). Optional — 100% present in the corpus.
     living_area: Optional[Union[int, float]] = None