diff --git a/BauSystem_Main/src/de/steamwar/bausystem/features/util/PistonCalculator.java b/BauSystem_Main/src/de/steamwar/bausystem/features/util/PistonCalculator.java
index 130af74e..fba74619 100644
--- a/BauSystem_Main/src/de/steamwar/bausystem/features/util/PistonCalculator.java
+++ b/BauSystem_Main/src/de/steamwar/bausystem/features/util/PistonCalculator.java
@@ -33,13 +33,15 @@ import org.bukkit.block.PistonMoveReaction;
 import org.bukkit.block.TileState;
 import org.bukkit.block.data.BlockData;
 import org.bukkit.block.data.type.Piston;
-import org.bukkit.block.data.type.PistonHead;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.Listener;
 import org.bukkit.event.block.Action;
 import org.bukkit.event.player.PlayerInteractEvent;
 
-import java.util.*;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 @Linked(LinkageType.LISTENER)
@@ -71,7 +73,7 @@ public class PistonCalculator implements Listener {
         if (facing != direction) calcOrigin = origin.getRelative(facing, 3);
 
         List<Block> toCalc = new LinkedList<>();
-        calcDirection(origin, calcOrigin, facing != direction ? origin.getRelative(facing) : null, facing, direction, blockSet, toCalc, unmovable);
+        calcDirection(origin, null, calcOrigin, facing != direction ? origin.getRelative(facing) : null, facing, direction, blockSet, toCalc, unmovable);
 
         while (!toCalc.isEmpty()) {
             Block current = toCalc.remove(0);
@@ -87,7 +89,7 @@ public class PistonCalculator implements Listener {
                 if (!isPiston(block) && (block.getPistonMoveReaction() == PistonMoveReaction.BLOCK || block.getPistonMoveReaction() == PistonMoveReaction.IGNORE || block.getPistonMoveReaction() == PistonMoveReaction.PUSH_ONLY || block.getState() instanceof TileState)) continue;
                 if (block.getType() != oppositeType) {
                     if (!blockSet.contains(block)) toCalc.add(block);
-                    calcDirection(null, block, null, facing, direction, blockSet, toCalc, unmovable);
+                    calcDirection(null, origin, block, null, facing, direction, blockSet, toCalc, unmovable);
                 }
             }
         }
@@ -97,7 +99,7 @@ public class PistonCalculator implements Listener {
         return new CalculationResult(blockSet.size(), blockSet.size() > 12, unmovable.get());
     }
 
-    private void calcDirection(Block origin, Block calcOrigin, Block ignore, BlockFace facing, BlockFace direction, Set<Block> blockSet, List<Block> toCalc, AtomicBoolean unmovable) {
+    private void calcDirection(Block origin, Block blockOrigin, Block calcOrigin, Block ignore, BlockFace facing, BlockFace direction, Set<Block> blockSet, List<Block> toCalc, AtomicBoolean unmovable) {
         for (int i = 1; i < 13; i++) {
             Block block = calcOrigin.getRelative(direction, i);
             if (block.equals(ignore)) return;
@@ -107,6 +109,10 @@ public class PistonCalculator implements Listener {
                 return;
             }
             if (block.getType().isAir()) return;
+            if (facing == direction && block.equals(blockOrigin)) {
+                unmovable.set(true);
+                return;
+            }
             if (facing != direction && (block.equals(origin) || block.getRelative(facing.getOppositeFace()).equals(origin))) return;
             if (!blockSet.contains(block)) toCalc.add(block);
         }