diff --git a/datatypes/epc/domain/tests/test_from_sap_schema.py b/datatypes/epc/domain/tests/test_from_sap_schema.py
index 5eb64a6ab..0e9c5bc92 100644
--- a/datatypes/epc/domain/tests/test_from_sap_schema.py
+++ b/datatypes/epc/domain/tests/test_from_sap_schema.py
@@ -106,6 +106,16 @@ class TestFromSapSchema17_1RebaselineFields:
 
         assert result.property_type == "2"
 
+    def test_maps_built_form_as_gov_code_string(self) -> None:
+        # built_form (gov code 1 in the fixture) → str, mirroring
+        # from_rdsap_schema_17_1; carried for the calculator's exposed-side /
+        # sheltered handling and the property-details panel.
+        schema = from_dict(SapSchema17_1, load("sap_17_1.json"))
+
+        result = EpcPropertyDataMapper.from_sap_schema_17_1(schema)
+
+        assert result.built_form == "1"
+
 
 class TestFullSapHasHotWaterCylinderFallback:
     """Some full-SAP certs (e.g. SAP-Schema-17.0 cert 8265-7433-3220-9736-7902)