diff --git a/OpenRa.Game/PlaceBuilding.cs b/OpenRa.Game/PlaceBuilding.cs
index 2f93642c06..8ddbe02eb6 100644
--- a/OpenRa.Game/PlaceBuilding.cs
+++ b/OpenRa.Game/PlaceBuilding.cs
@@ -20,7 +20,10 @@ namespace OpenRa.Game
 		public IEnumerable<Order> Order(int2 xy)
 		{
 			// todo: check that space is free
-			if (Footprint.Tiles(Rules.UnitInfo[Name], xy).Any(t => !Game.IsCellBuildable(t, UnitMovementType.Wheel)))
+			var bi = (UnitInfo.BuildingInfo)Rules.UnitInfo[Name];
+			if (Footprint.Tiles(bi, xy).Any(
+				t => !Game.IsCellBuildable(t, 
+					bi.WaterBound ? UnitMovementType.Float : UnitMovementType.Wheel)))
 				yield break;
 
 			yield return new PlaceBuildingOrder(this, xy);
diff --git a/OpenRa.Game/UiOverlay.cs b/OpenRa.Game/UiOverlay.cs
index f66150ca67..39c4f739fd 100644
--- a/OpenRa.Game/UiOverlay.cs
+++ b/OpenRa.Game/UiOverlay.cs
@@ -35,8 +35,10 @@ namespace OpenRa.Game
 			if (!hasOverlay)
 				return;
 
-			foreach( var t in Footprint.Tiles( Rules.UnitInfo[ name ], position ) )
-				spriteRenderer.DrawSprite( Game.IsCellBuildable( t, UnitMovementType.Wheel )
+			var bi = (UnitInfo.BuildingInfo)Rules.UnitInfo[name];
+			foreach( var t in Footprint.Tiles( bi, position ) )
+				spriteRenderer.DrawSprite( Game.IsCellBuildable( t, bi.WaterBound 
+					? UnitMovementType.Float : UnitMovementType.Wheel )
 					? buildOk : buildBlocked, Game.CellSize * t, 0 );
 
 			spriteRenderer.Flush();