diff --git a/domain/epc/property_overrides/roof_guard.py b/domain/epc/property_overrides/roof_guard.py
new file mode 100644
index 000000000..e3203e950
--- /dev/null
+++ b/domain/epc/property_overrides/roof_guard.py
@@ -0,0 +1,9 @@
+from __future__ import annotations
+
+from typing import Optional
+
+from domain.epc.property_overrides.roof_type import RoofType
+
+
+def roof_guard(description: str) -> Optional[RoofType]:
+    raise NotImplementedError
diff --git a/tests/domain/epc/test_roof_guard.py b/tests/domain/epc/test_roof_guard.py
new file mode 100644
index 000000000..afb86923b
--- /dev/null
+++ b/tests/domain/epc/test_roof_guard.py
@@ -0,0 +1,37 @@
+"""The composed roof guard wired into the roof `GuardedColumnClassifier`.
+
+Two deterministic roof guards compose ahead of the LLM fallback: the
+party-ceiling guard (#1376) and the sloping-ceiling guard (ADR-0066). A roof
+description that neither recognises returns None and reaches the LLM.
+"""
+
+from __future__ import annotations
+
+from domain.epc.property_overrides.roof_guard import roof_guard
+from domain.epc.property_overrides.roof_type import RoofType
+
+
+def test_party_ceiling_marker_resolves_to_its_party_member() -> None:
+    # Act
+    member = roof_guard("another dwelling above")
+
+    # Assert
+    assert member is RoofType.ADJACENT_ANOTHER_DWELLING_ABOVE
+
+
+def test_sloping_ceiling_marker_resolves_to_the_sloping_family() -> None:
+    # Act
+    member = roof_guard("PitchedWithSlopingCeiling: 150mm")
+
+    # Assert
+    assert member is RoofType.PITCHED_SLOPING_CEILING_150MM
+
+
+def test_a_plain_loft_description_is_left_for_the_llm() -> None:
+    # Neither deterministic guard recognises a loft depth, so it reaches the LLM.
+
+    # Act
+    member = roof_guard("Pitched, 150 mm loft insulation")
+
+    # Assert
+    assert member is None