diff --git a/backend/documents_parser/tests/test_summary_pdf_mapper_chain.py b/backend/documents_parser/tests/test_summary_pdf_mapper_chain.py
index de8218cf..e8eda558 100644
--- a/backend/documents_parser/tests/test_summary_pdf_mapper_chain.py
+++ b/backend/documents_parser/tests/test_summary_pdf_mapper_chain.py
@@ -41,6 +41,7 @@ from domain.sap.rdsap.cert_to_inputs import SAP_10_2_SPEC_PRICES, cert_to_inputs
 from domain.sap.worksheet.tests import (
     _elmhurst_worksheet_000474 as _w000474,
     _elmhurst_worksheet_000477 as _w000477,
+    _elmhurst_worksheet_000480 as _w000480,
 )
 
 _FIXTURES = Path(__file__).parent / "fixtures"
@@ -597,3 +598,33 @@ def test_from_elmhurst_site_notes_matches_hand_built_000477() -> None:
         f"hand-built EpcPropertyData for cohort cert 000477:\n  " +
         "\n  ".join(diffs)
     )
+
+
+def test_from_elmhurst_site_notes_matches_hand_built_000480() -> None:
+    # Arrange — _elmhurst_worksheet_000480.build_epc() is the canonical
+    # hand-built EpcPropertyData for cert U985-0001-000480 (mid-terrace
+    # with main + 1 extension + 19.83 m² RIR, gas combi); it cascades
+    # to the worksheet PDF's `SAP value 61.2986` at 1e-4. Routing the
+    # Summary PDF through the Elmhurst mapper MUST produce a load-
+    # bearing-field-equivalent EpcPropertyData; any divergence is a
+    # mapper-coverage gap to close as its own slice.
+    pages = _summary_pdf_to_textract_style_pages(_SUMMARY_000480_PDF)
+    site_notes = ElmhurstSiteNotesExtractor(pages).extract()
+    mapped = EpcPropertyDataMapper.from_elmhurst_site_notes(site_notes)
+    hand_built = _w000480.build_epc()
+
+    # Act
+    diffs: list[str] = []
+    for field_name in _LOAD_BEARING_FIELDS:
+        diffs.extend(_diff_load_bearing(
+            getattr(mapped, field_name, None),
+            getattr(hand_built, field_name, None),
+            field_name,
+        ))
+
+    # Assert
+    assert not diffs, (
+        f"{len(diffs)} load-bearing divergence(s) between mapped and "
+        f"hand-built EpcPropertyData for cohort cert 000480:\n  " +
+        "\n  ".join(diffs)
+    )