diff --git a/OpenRa.FileFormats/TileReference.cs b/OpenRa.FileFormats/TileReference.cs
index 484f75ec32..fa6a90f249 100644
--- a/OpenRa.FileFormats/TileReference.cs
+++ b/OpenRa.FileFormats/TileReference.cs
@@ -4,7 +4,7 @@ using System.Text;
 
 namespace OpenRa.FileFormats
 {
-	public class TileReference
+	public struct TileReference
 	{
 		public ushort tile;
 		public byte image;
diff --git a/OpenRa.Game/BuildingInfluenceMap.cs b/OpenRa.Game/BuildingInfluenceMap.cs
index a7846b2b8b..f207245468 100644
--- a/OpenRa.Game/BuildingInfluenceMap.cs
+++ b/OpenRa.Game/BuildingInfluenceMap.cs
@@ -48,6 +48,17 @@ namespace OpenRa.Game
 					++initialTileCount;
 				}
 
+			if (!((UnitInfo.BuildingInfo)a.unitInfo).BaseNormal)
+			{
+				while (!pq.Empty)
+				{
+					var c = pq.Pop();
+					influence[c.location.X, c.location.Y].First = c.actor;
+					influence[c.location.X, c.location.Y].Second = 0;
+				}
+				return;
+			}
+
 			Log.Write("Recalculating voronoi region for {{ {0} ({1},{2}) }}: {3} initial tiles",
 				a.unitInfo.Name, a.Location.X, a.Location.Y, initialTileCount);