diff --git a/tests/domain/modelling/test_roof_recommendation.py b/tests/domain/modelling/test_roof_recommendation.py
index 9e36b25f8..defc239cd 100644
--- a/tests/domain/modelling/test_roof_recommendation.py
+++ b/tests/domain/modelling/test_roof_recommendation.py
@@ -111,6 +111,25 @@ def test_vaulted_ceiling_with_nd_thickness_on_pre_1950_dwelling_yields_sloping_c
     )
 
 
+def test_vaulted_ceiling_with_nd_thickness_on_limited_insulation_age_band_yields_no_recommendation() -> None:
+    # Arrange — same vaulted-ND shape, but age band E: as-built carries limited
+    # insulation (ADR-0047), and ND must never make an undefined cert MORE
+    # eligible than an explicit thin lodgement (which is not eligible today).
+    baseline: EpcPropertyData = build_epc()
+    main: SapBuildingPart = _part(baseline, BuildingPartIdentifier.MAIN)
+    main.roof_construction_type = "Pitched (vaulted ceiling)"
+    main.roof_insulation_thickness = "ND"
+    main.construction_age_band = "E"
+
+    # Act
+    recommendation: Recommendation | None = recommend_roof_insulation(
+        baseline, _StubProducts()
+    )
+
+    # Assert
+    assert recommendation is None
+
+
 def test_loft_option_carries_cost_from_roof_area_and_product() -> None:
     # Arrange
     baseline: EpcPropertyData = build_epc()  # MAIN roof area 14.85 m^2