diff --git a/Source/AllModdingComponents/JecsTools/PlaceWorker_OnTopOfWalls.cs b/Source/AllModdingComponents/JecsTools/PlaceWorker_OnTopOfWalls.cs
index c1fb13b..34f490e 100644
--- a/Source/AllModdingComponents/JecsTools/PlaceWorker_OnTopOfWalls.cs
+++ b/Source/AllModdingComponents/JecsTools/PlaceWorker_OnTopOfWalls.cs
@@ -14,8 +14,8 @@ public override AcceptanceReport AllowsPlacing(BuildableDef checkingDef, IntVec3
 
         static bool IsWall(Thing thing)
         {
-            // In RW 1.3+, it seems like BuildingProperties.isPlaceOverableWall indicates whether something is a "wall".
-            if (thing.def.building?.isPlaceOverableWall ?? false)
+            // In RW 1.3+, it seems like BuildingProperties.isPlaceOverableWall or ThingDef.IsSmoothed indicates whether something is a "wall".
+            if (thing.def is { building: { isPlaceOverableWall: true } } or { IsSmoothed: true })
                 return true;
             // Legacy heuristic for mods that don't use isPlaceOverableWall.
             if (thing.def.defName.Contains("Wall"))