diff --git a/OpenRA.Mods.Cnc/OpenRA.Mods.Cnc.csproj b/OpenRA.Mods.Cnc/OpenRA.Mods.Cnc.csproj
index 6ba96ea6dc..b648538d9d 100644
--- a/OpenRA.Mods.Cnc/OpenRA.Mods.Cnc.csproj
+++ b/OpenRA.Mods.Cnc/OpenRA.Mods.Cnc.csproj
@@ -109,6 +109,7 @@
     <Compile Include="Traits\Chronoshiftable.cs" />
     <Compile Include="Traits\Cloneable.cs" />
     <Compile Include="Traits\Disguise.cs" />
+    <Compile Include="Traits\EnergyWall.cs" />
     <Compile Include="Traits\FrozenUnderFogUpdatedByGps.cs" />
     <Compile Include="Traits\HarvesterHuskModifier.cs" />
     <Compile Include="Traits\Infiltration\InfiltrateForCash.cs" />
diff --git a/OpenRA.Mods.Cnc/Traits/EnergyWall.cs b/OpenRA.Mods.Cnc/Traits/EnergyWall.cs
new file mode 100644
index 0000000000..067c0fd88b
--- /dev/null
+++ b/OpenRA.Mods.Cnc/Traits/EnergyWall.cs
@@ -0,0 +1,112 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2017 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,
+ * see COPYING.
+ */
+#endregion
+
+using System.Collections.Generic;
+using System.Linq;
+using OpenRA.GameRules;
+using OpenRA.Mods.Common.Traits;
+using OpenRA.Support;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Cnc.Traits
+{
+	[Desc("Will open and be passable for actors that appear friendly when there are no enemies in range.")]
+	public class EnergyWallInfo : BuildingInfo, IObservesVariablesInfo, IRulesetLoaded
+	{
+		[FieldLoader.Require]
+		[WeaponReference]
+		[Desc("The weapon to attack units on top of the wall with when activated.")]
+		public readonly string Weapon = null;
+
+		[ConsumedConditionReference]
+		[Desc("Boolean expression defining the condition to activate this trait.")]
+		public readonly BooleanExpression ActiveCondition = null;
+
+		public override object Create(ActorInitializer init) { return new EnergyWall(init, this); }
+
+		public WeaponInfo WeaponInfo { get; private set; }
+
+		public void RulesetLoaded(Ruleset rules, ActorInfo ai)
+		{
+			WeaponInfo weaponInfo;
+
+			var weaponToLower = Weapon.ToLowerInvariant();
+			if (!rules.Weapons.TryGetValue(weaponToLower, out weaponInfo))
+				throw new YamlException("Weapons Ruleset does not contain an entry '{0}'".F(weaponToLower));
+
+			WeaponInfo = weaponInfo;
+		}
+	}
+
+	public class EnergyWall : Building, IObservesVariables, ITick, ITemporaryBlocker
+	{
+		readonly EnergyWallInfo info;
+		IEnumerable<CPos> blockedPositions;
+
+		// Initial state is active to match Building adding the influence to the ActorMap
+		// This will be updated by ConditionsChanged at actor creation.
+		bool active = true;
+
+		public EnergyWall(ActorInitializer init, EnergyWallInfo info)
+			: base(init, info)
+		{
+			this.info = info;
+		}
+
+		public virtual IEnumerable<VariableObserver> GetVariableObservers()
+		{
+			if (info.ActiveCondition != null)
+				yield return new VariableObserver(ActiveConditionChanged, info.ActiveCondition.Variables);
+		}
+
+		void ActiveConditionChanged(Actor self, IReadOnlyDictionary<string, int> conditions)
+		{
+			if (info.ActiveCondition == null)
+				return;
+
+			var wasActive = active;
+			active = info.ActiveCondition.Evaluate(conditions);
+
+			if (!wasActive && active)
+				self.World.ActorMap.AddInfluence(self, this);
+			else if (wasActive && !active)
+				self.World.ActorMap.RemoveInfluence(self, this);
+		}
+
+		void ITick.Tick(Actor self)
+		{
+			if (!active)
+				return;
+
+			foreach (var loc in blockedPositions)
+			{
+				var blockers = self.World.ActorMap.GetActorsAt(loc).Where(a => !a.IsDead && a != self);
+				foreach (var blocker in blockers)
+					info.WeaponInfo.Impact(Target.FromActor(blocker), self, Enumerable.Empty<int>());
+			}
+		}
+
+		bool ITemporaryBlocker.IsBlocking(Actor self, CPos cell)
+		{
+			return active && blockedPositions.Contains(cell);
+		}
+
+		bool ITemporaryBlocker.CanRemoveBlockage(Actor self, Actor blocking)
+		{
+			return !active;
+		}
+
+		public override void AddedToWorld(Actor self)
+		{
+			base.AddedToWorld(self);
+			blockedPositions = FootprintUtils.Tiles(self);
+		}
+	}
+}