diff --git a/OpenRA.Mods.Common/Orders/PlaceBuildingOrderGenerator.cs b/OpenRA.Mods.Common/Orders/PlaceBuildingOrderGenerator.cs
index b47d5655ad..492efe2bc2 100644
--- a/OpenRA.Mods.Common/Orders/PlaceBuildingOrderGenerator.cs
+++ b/OpenRA.Mods.Common/Orders/PlaceBuildingOrderGenerator.cs
@@ -230,10 +230,10 @@ namespace OpenRA.Mods.Common.Orders
 				foreach (var r in previewRenderables)
 					yield return r;
 
-				var res = world.WorldActor.Trait<ResourceLayer>();
+				var res = world.WorldActor.TraitOrDefault<ResourceLayer>();
 				var isCloseEnough = buildingInfo.IsCloseEnoughToBase(world, world.LocalPlayer, building, topLeft);
 				foreach (var t in buildingInfo.Tiles(topLeft))
-					cells.Add(t, MakeCellType(isCloseEnough && world.IsCellBuildable(t, buildingInfo) && res.GetResource(t) == null));
+					cells.Add(t, MakeCellType(isCloseEnough && world.IsCellBuildable(t, buildingInfo) && (res == null || res.GetResource(t) == null)));
 			}
 
 			var cellPalette = wr.Palette(placeBuildingInfo.Palette);
diff --git a/OpenRA.Mods.Common/Traits/Buildings/BuildingUtils.cs b/OpenRA.Mods.Common/Traits/Buildings/BuildingUtils.cs
index 35c604f6dc..ff135dfece 100644
--- a/OpenRA.Mods.Common/Traits/Buildings/BuildingUtils.cs
+++ b/OpenRA.Mods.Common/Traits/Buildings/BuildingUtils.cs
@@ -43,9 +43,9 @@ namespace OpenRA.Mods.Common.Traits
 			if (building.AllowInvalidPlacement)
 				return true;
 
-			var res = world.WorldActor.Trait<ResourceLayer>();
+			var res = world.WorldActor.TraitOrDefault<ResourceLayer>();
 			return building.Tiles(topLeft).All(
-				t => world.Map.Contains(t) && res.GetResource(t) == null &&
+				t => world.Map.Contains(t) && (res == null || res.GetResource(t) == null) &&
 					world.IsCellBuildable(t, building, toIgnore));
 		}