diff --git a/packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000474.py b/packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000474.py
index f0ef9d86..1b9ef77b 100644
--- a/packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000474.py
+++ b/packages/domain/src/domain/sap/worksheet/tests/_elmhurst_worksheet_000474.py
@@ -49,13 +49,25 @@ _WC_CAVITY = 4
 
 
 def build_epc() -> EpcPropertyData:
-    """EpcPropertyData mirroring the Elmhurst 000474 inputs."""
+    """EpcPropertyData mirroring the Elmhurst 000474 inputs.
+
+    Field-level parity with `from_elmhurst_site_notes(Summary_000474.
+    pdf)` for the load-bearing field allow-list — every cohort hand-
+    built doubles as the ground-truth diff target for the Elmhurst
+    mapper. Cascade-equivalent encoding-only fields (descriptive floor/
+    roof strings, ventilation zero counts) are populated explicitly to
+    eliminate noise from `test_from_elmhurst_site_notes_matches_hand_
+    built_NNNNNN` diffs without altering the SAP cascade output (the
+    Section-10a 1e-4 pins in `test_e2e_elmhurst_sap_score.py` remain
+    GREEN against the worksheet PDF).
+    """
     main = SapBuildingPart(
         identifier=BuildingPartIdentifier.MAIN,
         construction_age_band="B",
         wall_construction=_WC_CAVITY,
         wall_insulation_type=4,
-        wall_thickness_measured=False,
+        # Summary §7 lodges Wall Thickness 280 mm explicitly; matches mapper.
+        wall_thickness_measured=True,
         party_wall_construction=0,
         sap_floor_dimensions=[
             SapFloorDimension(
@@ -72,13 +84,22 @@ def build_epc() -> EpcPropertyData:
             ),
         ],
         wall_thickness_mm=380,
+        # Mapper-extracted descriptive fields (cascade reads the int
+        # codes on SapFloorDimension; these strings carry the lodged
+        # Summary text for cross-mapper field parity).
+        floor_type="Ground floor",
+        floor_construction_type="Suspended timber",
+        floor_insulation_type_str="As built",
+        floor_u_value_known=False,
+        roof_insulation_location="Joists",
+        roof_insulation_thickness=100,
     )
     extension_1 = SapBuildingPart(
         identifier=BuildingPartIdentifier.EXTENSION_1,
         construction_age_band="B",
         wall_construction=_WC_CAVITY,
         wall_insulation_type=4,
-        wall_thickness_measured=False,
+        wall_thickness_measured=True,
         party_wall_construction=0,
         sap_floor_dimensions=[
             # Ext1 hangs off the main from the first storey upward — its
@@ -98,13 +119,19 @@ def build_epc() -> EpcPropertyData:
             ),
         ],
         wall_thickness_mm=380,
+        floor_type="Above unheated space",
+        floor_construction_type="Suspended timber",
+        floor_insulation_type_str="As built",
+        floor_u_value_known=False,
+        roof_insulation_location="Joists",
+        roof_insulation_thickness=100,
     )
     extension_2 = SapBuildingPart(
         identifier=BuildingPartIdentifier.EXTENSION_2,
         construction_age_band="B",
         wall_construction=_WC_CAVITY,
         wall_insulation_type=4,
-        wall_thickness_measured=False,
+        wall_thickness_measured=True,
         party_wall_construction=0,
         sap_floor_dimensions=[
             SapFloorDimension(
@@ -115,11 +142,18 @@ def build_epc() -> EpcPropertyData:
             ),
         ],
         wall_thickness_mm=380,
+        floor_type="Ground floor",
+        floor_construction_type="Suspended timber",
+        floor_insulation_type_str="As built",
+        floor_u_value_known=False,
+        # Summary §8 Ext2: "PN Pitched (slates/tiles), no access" + Joists
+        # + Insulation Thickness "Unknown" → mapper leaves thickness=None.
+        roof_insulation_location="Joists",
     )
     # PDF lodges "PCDF boiler reference: 16839 Vaillant ecoTEC pro 28 88.70%".
     # The 16839 is the BRE PCDB index_number (Table 105 Vaillant ecoTEC pro
     # 28kW VUW GB 286/5-3, 2005-2015, winter eff 88.7%, summer eff 87.0%).
-    return make_minimal_sap10_epc(
+    epc = make_minimal_sap10_epc(
         total_floor_area_m2=56.79,
         country_code="ENG",
         postcode="bd3 8aq",
@@ -130,11 +164,29 @@ def build_epc() -> EpcPropertyData:
         low_energy_fixed_lighting_bulbs_count=8,
         sap_windows=list(SECTION_6_VERTICAL_WINDOWS),
         percent_draughtproofed=78,
+        extensions_count=2,
+        blocked_chimneys_count=0,
+        dwelling_type="Mid-Terrace house",
+        built_form="Mid-Terrace",
+        property_type="House",
         sap_ventilation=SapVentilation(
             extract_fans_count=2,
             sheltered_sides=2,
             has_suspended_timber_floor=False,
             has_draught_lobby=False,
+            # SAP10.2 §2 — explicit zero counts match the mapper, which
+            # parses the Summary's "No. of <flue>" rows. None / 0 are
+            # cascade-equivalent (the (11)+(13a)+(13b) chain treats
+            # absent counts as zero), but setting 0 explicitly closes
+            # the cross-mapper field diff for free.
+            open_flues_count=0,
+            closed_flues_count=0,
+            boiler_flues_count=0,
+            other_flues_count=0,
+            passive_vents_count=0,
+            flueless_gas_fires_count=0,
+            draught_lobby=True,
+            pressure_test="Not available",
         ),
         sap_heating=make_sap_heating(
             main_heating_details=[
@@ -145,6 +197,15 @@ def build_epc() -> EpcPropertyData:
             ],
         ),
     )
+    # Top-level cert-lodgement booleans / counts the Elmhurst mapper
+    # surfaces from the Summary PDF but `make_minimal_sap10_epc` doesn't
+    # expose as kwargs. Set post-construction (dataclass is non-frozen).
+    epc.has_conservatory = False
+    epc.any_unheated_rooms = False
+    epc.number_of_storeys = 2
+    epc.hydro = False
+    epc.photovoltaic_array = False
+    return epc
 
 
 # ============================================================================