diff --git a/OpenRA.Mods.D2k/Traits/Buildings/D2kActorPreviewPlaceBuildingPreview.cs b/OpenRA.Mods.D2k/Traits/Buildings/D2kActorPreviewPlaceBuildingPreview.cs
index 858ce441db..df233d26a1 100644
--- a/OpenRA.Mods.D2k/Traits/Buildings/D2kActorPreviewPlaceBuildingPreview.cs
+++ b/OpenRA.Mods.D2k/Traits/Buildings/D2kActorPreviewPlaceBuildingPreview.cs
@@ -25,6 +25,9 @@ namespace OpenRA.Mods.D2k.Traits
 		[Desc("Terrain types that should show the 'unsafe' footprint tile.")]
 		public readonly HashSet<string> UnsafeTerrainTypes = new HashSet<string> { "Rock" };
 
+		[Desc("Only check for 'unsafe' footprint tiles when you have these prerequisites.")]
+		public readonly string[] RequiresPrerequisites = { };
+
 		protected override IPlaceBuildingPreview CreatePreview(WorldRenderer wr, ActorInfo ai, TypeDictionary init)
 		{
 			return new D2kActorPreviewPlaceBuildingPreviewPreview(wr, ai, this, init);
@@ -41,6 +44,7 @@ namespace OpenRA.Mods.D2k.Traits
 	class D2kActorPreviewPlaceBuildingPreviewPreview : ActorPreviewPlaceBuildingPreviewPreview
 	{
 		readonly D2kActorPreviewPlaceBuildingPreviewInfo info;
+		readonly bool checkUnsafeTiles;
 		readonly Sprite buildOk;
 		readonly Sprite buildUnsafe;
 		readonly Sprite buildBlocked;
@@ -54,6 +58,9 @@ namespace OpenRA.Mods.D2k.Traits
 			var world = wr.World;
 			var sequences = world.Map.Rules.Sequences;
 
+			var techTree = init.Get<OwnerInit>().Value(world).PlayerActor.Trait<TechTree>();
+			checkUnsafeTiles = info.RequiresPrerequisites.Any() && techTree.HasPrerequisites(info.RequiresPrerequisites);
+
 			buildOk = sequences.GetSequence("overlay", "build-valid").GetSprite(0);
 			buildUnsafe = sequences.GetSequence("overlay", "build-unsafe").GetSprite(0);
 			buildBlocked = sequences.GetSequence("overlay", "build-invalid").GetSprite(0);
@@ -76,7 +83,7 @@ namespace OpenRA.Mods.D2k.Traits
 					continue;
 
 				var tile = HasFlag(c.Value, PlaceBuildingCellType.Invalid) ? buildBlocked :
-					candidateSafeTiles.Contains(c.Key) && info.UnsafeTerrainTypes.Contains(wr.World.Map.GetTerrainInfo(c.Key).Type)
+					(checkUnsafeTiles && candidateSafeTiles.Contains(c.Key) && info.UnsafeTerrainTypes.Contains(wr.World.Map.GetTerrainInfo(c.Key).Type))
 					? buildUnsafe : buildOk;
 
 				var pal = HasFlag(c.Value, PlaceBuildingCellType.LineBuild) ? linePalette : cellPalette;
diff --git a/mods/d2k/rules/defaults.yaml b/mods/d2k/rules/defaults.yaml
index 8aada48dfb..d975229cfb 100644
--- a/mods/d2k/rules/defaults.yaml
+++ b/mods/d2k/rules/defaults.yaml
@@ -410,6 +410,7 @@
 		TerrainTypes: Rock, Concrete
 		BuildSounds: BUILD1.WAV
 	D2kActorPreviewPlaceBuildingPreview:
+		RequiresPrerequisites: !global-auto-concrete
 		OverridePalette: placebuilding
 	RequiresBuildableArea:
 		AreaTypes: building
@@ -447,12 +448,20 @@
 		SellSounds: BUILD1.WAV
 	Guardable:
 		Range: 3c0
+	GrantConditionOnPrerequisite@AUTOCONCRETE:
+		Condition: auto-concrete
+		Prerequisites: global-auto-concrete
 	DamagedByTerrain:
+		RequiresCondition: !auto-concrete
 		Damage: 500
 		DamageInterval: 100
 		Terrain: Rock
 		DamageThreshold: 50
 		StartOnThreshold: true
+	LaysTerrain:
+		RequiresCondition: auto-concrete
+		TerrainTypes: Rock
+		Template: 88
 	ThrowsShrapnel:
 		Weapons: Debris, Debris2, Debris3, Debris4
 		Pieces: 2, 5
diff --git a/mods/d2k/rules/player.yaml b/mods/d2k/rules/player.yaml
index f9322a150a..abeb85deb9 100644
--- a/mods/d2k/rules/player.yaml
+++ b/mods/d2k/rules/player.yaml
@@ -98,10 +98,17 @@ Player:
 		CashTickUpNotification: CashTickUp
 		CashTickDownNotification: CashTickDown
 	DeveloperMode:
-		CheckboxDisplayOrder: 7
+		CheckboxDisplayOrder: 8
 	BaseAttackNotifier:
 	Shroud:
 		FogCheckboxDisplayOrder: 3
+	LobbyPrerequisiteCheckbox@AUTOCONCRETE:
+		ID: autoconcrete
+		Label: Automatic Concrete
+		Description: Concrete foundations are automatically created beneath buildings
+		Enabled: False
+		DisplayOrder: 7
+		Prerequisites: global-auto-concrete
 	FrozenActorLayer:
 	HarvesterAttackNotifier:
 	PlayerStatistics:
diff --git a/mods/d2k/rules/structures.yaml b/mods/d2k/rules/structures.yaml
index f4129d80f1..be1fec0986 100644
--- a/mods/d2k/rules/structures.yaml
+++ b/mods/d2k/rules/structures.yaml
@@ -34,6 +34,7 @@ concretea:
 		Cost: 20
 	Buildable:
 		BuildPaletteOrder: 110
+		Prerequisites: ~!global-auto-concrete
 		BuildDuration: 62
 		BuildDurationModifier: 100
 
@@ -48,7 +49,7 @@ concreteb:
 		Cost: 50
 	Buildable:
 		BuildPaletteOrder: 210
-		Prerequisites: upgrade.conyard
+		Prerequisites: upgrade.conyard, ~!global-auto-concrete
 		BuildDuration: 94
 		BuildDurationModifier: 100
 
@@ -64,8 +65,7 @@ construction_yard:
 		Dimensions: 3,3
 		LocalCenterOffset: 0,-512,0
 	LaysTerrain:
-		TerrainTypes: Rock
-		Template: 88
+		-RequiresCondition:
 	WithBuildingBib:
 	Selectable:
 		Bounds: 96,64