diff --git a/domain/modelling/generators/solid_wall_recommendation.py b/domain/modelling/generators/solid_wall_recommendation.py
index 9d4a67e0..3454341e 100644
--- a/domain/modelling/generators/solid_wall_recommendation.py
+++ b/domain/modelling/generators/solid_wall_recommendation.py
@@ -40,6 +40,10 @@ _WALL_TIMBER_FRAME: Final[int] = 5
 # disambiguated from basement by `main_wall_is_basement` below — a basement wall
 # is never solid-wall-insulation-suitable regardless.
 _WALL_SYSTEM_BUILT: Final[int] = 6
+# Park home (`PH`, the Elmhurst code-8 wall) — NOT system-built (ADR-0019: "do
+# not key system-built on 8"). A park home's wall is a proprietary panel system
+# our EWI/IWI model doesn't represent, so it is never solid-wall-suitable.
+_WALL_PARK_HOME: Final[int] = 8
 # `wall_insulation_type`: 4 = as-built / assumed (uninsulated) — the trigger.
 _WALL_AS_BUILT: Final[int] = 4
 # `wall_insulation_type` the overlay lodges: 1 = external, 3 = internal.
@@ -142,6 +146,8 @@ def recommend_solid_wall(
     construction: object = main.wall_construction
     if not isinstance(construction, int):
         return None  # a free-text site-notes construction is not a code we key on
+    if construction == _WALL_PARK_HOME:
+        return None  # park home (code 8) — proprietary panel, never EWI/IWI
     measure_types = _CONSTRUCTABLE_OPTIONS.get(construction)
     if not measure_types:
         return None
diff --git a/tests/domain/modelling/test_wall_recommendation.py b/tests/domain/modelling/test_wall_recommendation.py
index 182ce2a3..b47d9eb1 100644
--- a/tests/domain/modelling/test_wall_recommendation.py
+++ b/tests/domain/modelling/test_wall_recommendation.py
@@ -12,6 +12,7 @@ from domain.modelling.scoring.overlay_applicator import apply_simulations
 from domain.modelling.product import Product
 from domain.modelling.recommendation import Recommendation
 from domain.modelling.generators.wall_recommendation import recommend_cavity_wall
+from domain.modelling.generators.solid_wall_recommendation import recommend_solid_wall
 from repositories.product.product_repository import ProductRepository
 from tests.domain.sap10_calculator.worksheet._elmhurst_worksheet_000490 import (
     build_epc,
@@ -87,3 +88,21 @@ def test_non_cavity_main_wall_yields_no_recommendation() -> None:
 
     # Assert
     assert recommendation is None
+
+
+def test_park_home_wall_yields_no_solid_wall_recommendation() -> None:
+    # Arrange — a park home (wall_construction code 8) with an uninsulated
+    # as-built wall. Code 8 is NOT system-built (ADR-0019); a park home's
+    # proprietary panel is never EWI/IWI-suitable, so the generator excludes it.
+    baseline: EpcPropertyData = build_epc()
+    main: SapBuildingPart = _part(baseline, BuildingPartIdentifier.MAIN)
+    main.wall_construction = 8
+    main.wall_insulation_type = 4  # as-built / uninsulated — the trigger
+
+    # Act
+    recommendation: Recommendation | None = recommend_solid_wall(
+        baseline, _StubProducts()
+    )
+
+    # Assert
+    assert recommendation is None