diff --git a/OpenRA.Mods.RA/Render/RenderBuildingWall.cs b/OpenRA.Mods.RA/Render/RenderBuildingWall.cs
index ee1bdddc20..7a25fe890e 100644
--- a/OpenRA.Mods.RA/Render/RenderBuildingWall.cs
+++ b/OpenRA.Mods.RA/Render/RenderBuildingWall.cs
@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2011 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2014 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation. For more information,
@@ -15,56 +15,86 @@ namespace OpenRA.Mods.RA.Render
 {
 	class RenderBuildingWallInfo : RenderBuildingInfo
 	{
-		public override object Create(ActorInitializer init) { return new RenderBuildingWall( init, this ); }
+		public readonly string Sequence = "idle";
+
+		public override object Create(ActorInitializer init) { return new RenderBuildingWall(init, this); }
 	}
 
-	class RenderBuildingWall : RenderBuilding, INotifyBuildComplete
+	class RenderBuildingWall : RenderBuilding, INotifyBuildComplete, INotifyAddedToWorld, INotifyRemovedFromWorld
 	{
-		string seqName;
-		int adjacentWalls = 0;
+		readonly RenderBuildingWallInfo info;
+		int adjacent = 0;
+		bool dirty = true;
 
-		public RenderBuildingWall( ActorInitializer init, RenderBuildingInfo info )
+		public RenderBuildingWall(ActorInitializer init, RenderBuildingWallInfo info)
 			: base(init, info)
 		{
-			seqName = "idle";
+			this.info = info;
 		}
 
-		public void BuildingComplete( Actor self )
+		public void BuildingComplete(Actor self)
 		{
-			anim.PlayFetchIndex(seqName, () => adjacentWalls);
+			anim.PlayFetchIndex(info.Sequence, () => adjacent);
 		}
 
 		public override void DamageStateChanged(Actor self, AttackInfo e)
 		{
-			anim.PlayFetchIndex(NormalizeSequence(anim, e.DamageState, "idle"), () => adjacentWalls);
+			anim.PlayFetchIndex(NormalizeSequence(anim, e.DamageState, info.Sequence), () => adjacent);
 		}
 
-		bool hasTicked = false;
 		public override void Tick(Actor self)
 		{
 			base.Tick(self);
 
-			if (!hasTicked)
-			{
-				var vec = new CVec(1, 1);
-				var adjWalls = self.World.FindActorsInBox(self.Location - vec, self.Location + vec)
-					.Where(a => a.Info == self.Info && a != self);
+			if (!dirty)
+				return;
 
-				foreach (var w in adjWalls)
-				{
-					w.Trait<RenderBuildingWall>().AddAdjacentWall(w.Location, self.Location);
-					AddAdjacentWall(self.Location, w.Location);
-				}
-				hasTicked = true;
+			// Update connection to neighbours
+			var vec = new CVec(1, 1);
+			var adjacentActors = self.World.FindActorsInBox(self.Location - vec, self.Location + vec);
+
+			adjacent = 0;
+			foreach (var a in adjacentActors)
+			{
+				var rb = a.TraitOrDefault<RenderBuildingWall>();
+				if (rb == null)
+					continue;
+
+				var location = self.Location;
+				var otherLocation = a.Location;
+
+				if (otherLocation == location + new CVec(0, -1))
+					adjacent |= 1;
+				else if (otherLocation == location + new CVec(+1, 0))
+					adjacent |= 2;
+				else if (otherLocation == location + new CVec(0, +1))
+					adjacent |= 4;
+				else if (otherLocation == location + new CVec(-1, 0))
+					adjacent |= 8;
 			}
+
+			dirty = false;
 		}
 
-		void AddAdjacentWall(CPos location, CPos otherLocation)
+		void UpdateNeighbours(Actor self)
 		{
-			if (otherLocation == location + new CVec(0, -1)) adjacentWalls |= 1;
-			if (otherLocation == location + new CVec(+1, 0)) adjacentWalls |= 2;
-			if (otherLocation == location + new CVec(0, +1)) adjacentWalls |= 4;
-			if (otherLocation == location + new CVec(-1, 0)) adjacentWalls |= 8;
+			var vec = new CVec(1, 1);
+			var neighbours = self.World.FindActorsInBox(self.Location - vec, self.Location + vec)
+				.Select(a => a.TraitOrDefault<RenderBuildingWall>())
+				.Where(a => a != null);
+
+			foreach (var rb in neighbours)
+				rb.dirty = true;
+		}
+
+		public void AddedToWorld(Actor self)
+		{
+			UpdateNeighbours(self);
+		}
+
+		public void RemovedFromWorld(Actor self)
+		{
+			UpdateNeighbours(self);
 		}
 	}
 }