diff --git a/OpenRA.Game/Map/Map.cs b/OpenRA.Game/Map/Map.cs
index 1985da8503..23680ea3d7 100644
--- a/OpenRA.Game/Map/Map.cs
+++ b/OpenRA.Game/Map/Map.cs
@@ -58,15 +58,12 @@ namespace OpenRA
 
 	public class MapOptions
 	{
-		public bool? AllyBuildRadius;
 		public string TechLevel;
 		public string[] Difficulties = { };
 		public bool? ShortGame;
 
 		public void UpdateServerSettings(Session.Global settings)
 		{
-			if (AllyBuildRadius.HasValue)
-				settings.AllyBuildRadius = AllyBuildRadius.Value;
 			if (ShortGame.HasValue)
 				settings.ShortGame = ShortGame.Value;
 		}
diff --git a/OpenRA.Mods.Common/OpenRA.Mods.Common.csproj b/OpenRA.Mods.Common/OpenRA.Mods.Common.csproj
index f19e4b8e08..4190885ebc 100644
--- a/OpenRA.Mods.Common/OpenRA.Mods.Common.csproj
+++ b/OpenRA.Mods.Common/OpenRA.Mods.Common.csproj
@@ -733,6 +733,7 @@
     <Compile Include="ColorValidator.cs" />
     <Compile Include="UtilityCommands\ResizeMapCommand.cs" />
     <Compile Include="Traits\World\MapCreeps.cs" />
+    <Compile Include="Traits\World\MapBuildRadius.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <PropertyGroup>
diff --git a/OpenRA.Mods.Common/ServerTraits/LobbyCommands.cs b/OpenRA.Mods.Common/ServerTraits/LobbyCommands.cs
index 5d5320faf2..8f8310da0f 100644
--- a/OpenRA.Mods.Common/ServerTraits/LobbyCommands.cs
+++ b/OpenRA.Mods.Common/ServerTraits/LobbyCommands.cs
@@ -569,7 +569,8 @@ namespace OpenRA.Mods.Common.Server
 							return true;
 						}
 
-						if (server.Map.Options.AllyBuildRadius.HasValue)
+						var mapBuildRadius = server.Map.Rules.Actors["world"].TraitInfoOrDefault<MapBuildRadiusInfo>();
+						if (mapBuildRadius == null || mapBuildRadius.AllyBuildRadiusLocked)
 						{
 							server.SendOrderTo(conn, "Message", "Map has disabled ally build radius configuration.");
 							return true;
@@ -1035,6 +1036,9 @@ namespace OpenRA.Mods.Common.Server
 			var startingUnits = server.Map.Rules.Actors["world"].TraitInfoOrDefault<SpawnMPUnitsInfo>();
 			gs.StartingUnitsClass = startingUnits == null ? "none" : startingUnits.StartingUnitsClass;
 
+			var mapBuildRadius = server.Map.Rules.Actors["world"].TraitInfoOrDefault<MapBuildRadiusInfo>();
+			gs.AllyBuildRadius = mapBuildRadius != null && mapBuildRadius.AllyBuildRadiusEnabled;
+
 			server.Map.Options.UpdateServerSettings(server.LobbyInfo.GlobalSettings);
 		}
 
diff --git a/OpenRA.Mods.Common/Traits/World/MapBuildRadius.cs b/OpenRA.Mods.Common/Traits/World/MapBuildRadius.cs
new file mode 100644
index 0000000000..d3becc3a00
--- /dev/null
+++ b/OpenRA.Mods.Common/Traits/World/MapBuildRadius.cs
@@ -0,0 +1,28 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2016 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, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System.Collections.Generic;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Traits
+{
+	[Desc("Controls the build radius checkboxes in the lobby options.")]
+	public class MapBuildRadiusInfo : TraitInfo<MapBuildRadius>
+	{
+		[Desc("Default value of the ally build radius checkbox in the lobby.")]
+		public readonly bool AllyBuildRadiusEnabled = true;
+
+		[Desc("Prevent the ally build radius state from being changed in the lobby.")]
+		public readonly bool AllyBuildRadiusLocked = false;
+	}
+
+	public class MapBuildRadius { }
+}
diff --git a/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyLogic.cs
index b33cbd46a5..d4d61c6d5f 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyLogic.cs
@@ -391,8 +391,14 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			var allybuildradius = optionsBin.GetOrNull<CheckboxWidget>("ALLYBUILDRADIUS_CHECKBOX");
 			if (allybuildradius != null)
 			{
+				var allyBuildRadiusLocked = new CachedTransform<Map, bool>(map =>
+				{
+					var mapBuildRadius = map.Rules.Actors["world"].TraitInfoOrDefault<MapBuildRadiusInfo>();
+					return mapBuildRadius == null || mapBuildRadius.AllyBuildRadiusLocked;
+				});
+
 				allybuildradius.IsChecked = () => orderManager.LobbyInfo.GlobalSettings.AllyBuildRadius;
-				allybuildradius.IsDisabled = () => configurationDisabled() || Map.Options.AllyBuildRadius.HasValue;
+				allybuildradius.IsDisabled = () => configurationDisabled() || allyBuildRadiusLocked.Update(Map);
 				allybuildradius.OnClick = () => orderManager.IssueOrder(Order.Command(
 					"allybuildradius {0}".F(!orderManager.LobbyInfo.GlobalSettings.AllyBuildRadius)));
 			}
diff --git a/mods/cnc/rules/world.yaml b/mods/cnc/rules/world.yaml
index 588310043a..7a0a5d3b46 100644
--- a/mods/cnc/rules/world.yaml
+++ b/mods/cnc/rules/world.yaml
@@ -74,6 +74,7 @@ World:
 	WarheadDebugOverlay:
 	MapCreeps:
 	SpawnMapActors:
+	MapBuildRadius:
 	MPStartLocations:
 	CreateMPPlayers:
 	MPStartUnits@mcvonly:
diff --git a/mods/d2k/rules/world.yaml b/mods/d2k/rules/world.yaml
index 5a8ac60f62..74e52b12ca 100644
--- a/mods/d2k/rules/world.yaml
+++ b/mods/d2k/rules/world.yaml
@@ -89,6 +89,7 @@ World:
 		SmokePercentage: 0
 	MapCreeps:
 	SpawnMapActors:
+	MapBuildRadius:
 	CreateMPPlayers:
 	MPStartLocations:
 	MPStartUnits@mcv:
diff --git a/mods/ra/rules/world.yaml b/mods/ra/rules/world.yaml
index 7a1be7743b..78c91500c7 100644
--- a/mods/ra/rules/world.yaml
+++ b/mods/ra/rules/world.yaml
@@ -120,6 +120,7 @@ World:
 	PathfinderDebugOverlay:
 	WarheadDebugOverlay:
 	SpawnMapActors:
+	MapBuildRadius:
 	CreateMPPlayers:
 	MPStartUnits@mcvonly:
 		Class: none
diff --git a/mods/ts/rules/world.yaml b/mods/ts/rules/world.yaml
index 0d1204d59e..cecc6d4194 100644
--- a/mods/ts/rules/world.yaml
+++ b/mods/ts/rules/world.yaml
@@ -98,6 +98,7 @@ World:
 	PathfinderDebugOverlay:
 	WarheadDebugOverlay:
 	SpawnMapActors:
+	MapBuildRadius:
 	CreateMPPlayers:
 	MPStartUnits@MCV:
 		Class: none