diff --git a/isometric-park-fna/Engines/BuildToolEngine.cs b/isometric-park-fna/Engines/BuildToolEngine.cs
--- a/isometric-park-fna/Engines/BuildToolEngine.cs
+++ b/isometric-park-fna/Engines/BuildToolEngine.cs
@@ -6,6 +6,7 @@
 using Microsoft.Xna.Framework.Input;
 
 using Encompass;
+using JM.LinqFaster;
 
 using isometricparkfna.Messages;
 using isometricparkfna.Components;
@@ -18,7 +19,9 @@
             // typeof(SelectedComponent),
             typeof(PreserveComponent))]
     [Reads(typeof(SelectedComponent),
-           typeof(AreaComponent))]
+            typeof(ContractStatusComponent),
+           typeof(AreaComponent),
+           typeof(PreserveComponent))]
     public class BuildToolEngine : Engine {
 
         private CellMap Map;
@@ -43,6 +46,26 @@
         }
 
         public override void Update(double dt) {
+            var occupied = new List<Vector2>();
+            foreach (var (entity, status) in ReadEntities<AreaComponent>()
+                    .WhereF((e) => HasComponent<ContractStatusComponent>(e))
+                    .SelectWhereF((e) => (e, GetComponent<ContractStatusComponent>(e)),
+                        (e) => ((e.Item2.status != ContractStatus.Broken) 
+                            && (e.Item2.status != ContractStatus.Rejected) 
+                            && (e.Item2.status != ContractStatus.Expired)
+                            && (e.Item2.status != ContractStatus.Completed)
+                            && (e.Item2.status != ContractStatus.Proposed))
+                        )) {
+                var entitySquares = GetComponent<AreaComponent>(entity).squares;
+                occupied.AddRange(entitySquares);
+            }
+            foreach (var entity in ReadEntities<AreaComponent>()
+                    .WhereF((e) => HasComponent<PreserveComponent>(e))) {
+                var entitySquares = GetComponent<AreaComponent>(entity).squares;
+                occupied.AddRange(entitySquares);
+            }
+
+
 
             foreach (ref readonly var message in ReadMessages<SpawnSelection>())
             {
@@ -77,7 +100,10 @@
 
                             foreach (var i in step_until(area.squares[0].X, end_x)) {
                                 foreach (var j in step_until(area.squares[0].Y, end_y)) {
-                                    newSquares.Add(new Vector2(i, j));
+                                    var newSquare = new Vector2(i, j);
+                                    if (!occupied.Contains(newSquare)) {
+                                        newSquares.Add(newSquare);
+                                    }
                                 }
                             }