diff --git a/src/main/java/world/bentobox/greenhouses/greenhouse/MinMaxXZ.java b/src/main/java/world/bentobox/greenhouses/greenhouse/MinMaxXZ.java
new file mode 100644
index 0000000..04b0a94
--- /dev/null
+++ b/src/main/java/world/bentobox/greenhouses/greenhouse/MinMaxXZ.java
@@ -0,0 +1,49 @@
+package world.bentobox.greenhouses.greenhouse;
+
+/**
+ * Holds min, max x and z coords and provides the area
+ * @author tastybento
+ *
+ */
+public abstract class MinMaxXZ {
+
+    protected int minX;
+    protected int maxX;
+    protected int minZ;
+    protected int maxZ;
+
+    /**
+     * @return the minX
+     */
+    public int getMinX() {
+        return minX;
+    }
+
+    /**
+     * @return the maxX
+     */
+    public int getMaxX() {
+        return maxX;
+    }
+
+    /**
+     * @return the minZ
+     */
+    public int getMinZ() {
+        return minZ;
+    }
+
+    /**
+     * @return the maxZ
+     */
+    public int getMaxZ() {
+        return maxZ;
+    }
+
+    /**
+     * @return the area
+     */
+    public int getArea() {
+        return (maxX - minX) * (maxZ - minZ);
+    }
+}
diff --git a/src/main/java/world/bentobox/greenhouses/greenhouse/Roof.java b/src/main/java/world/bentobox/greenhouses/greenhouse/Roof.java
index e93a472..873ffda 100644
--- a/src/main/java/world/bentobox/greenhouses/greenhouse/Roof.java
+++ b/src/main/java/world/bentobox/greenhouses/greenhouse/Roof.java
@@ -15,12 +15,8 @@ import org.bukkit.util.Vector;
  * @author tastybento
  *
  */
-public class Roof {
+public class Roof extends MinMaxXZ {
     private final Location location;
-    private int minX;
-    private int maxX;
-    private int minZ;
-    private int maxZ;
     private final int height;
     private boolean roofFound;
 
@@ -158,40 +154,6 @@ public class Roof {
         }
     }
 
-    /**
-     * @return the minX
-     */
-    public int getMinX() {
-        return minX;
-    }
-
-    /**
-     * @return the maxX
-     */
-    public int getMaxX() {
-        return maxX;
-    }
-
-    /**
-     * @return the minZ
-     */
-    public int getMinZ() {
-        return minZ;
-    }
-
-    /**
-     * @return the maxZ
-     */
-    public int getMaxZ() {
-        return maxZ;
-    }
-
-    /**
-     * @return the area
-     */
-    public int getArea() {
-        return (maxX - minX) * (maxZ - minZ);
-    }
     /**
      * @return the roofFound
      */
diff --git a/src/main/java/world/bentobox/greenhouses/greenhouse/Walls.java b/src/main/java/world/bentobox/greenhouses/greenhouse/Walls.java
index b5956c7..825b347 100644
--- a/src/main/java/world/bentobox/greenhouses/greenhouse/Walls.java
+++ b/src/main/java/world/bentobox/greenhouses/greenhouse/Walls.java
@@ -9,14 +9,10 @@ import org.bukkit.Material;
 import org.bukkit.World;
 import org.bukkit.block.BlockFace;
 
-public class Walls {
-    private int minX;
-    private int maxX;
-    private int minZ;
-    private int maxZ;
+public class Walls extends MinMaxXZ {
     private int floor;
 
-    public static final List<BlockFace> ORDINALS = Arrays.asList(BlockFace.NORTH, BlockFace.SOUTH, BlockFace.EAST, BlockFace.WEST);
+    private static final List<BlockFace> ORDINALS = Arrays.asList(BlockFace.NORTH, BlockFace.SOUTH, BlockFace.EAST, BlockFace.WEST);
 
     /**
      * @return list of valid wall blocks
@@ -151,36 +147,6 @@ public class Walls {
 
     }
 
-    /**
-     * @return the minXX
-     */
-    public int getMinX() {
-        return minX;
-    }
-    /**
-     * @return the maxXX
-     */
-    public int getMaxX() {
-        return maxX;
-    }
-    /**
-     * @return the minZZ
-     */
-    public int getMinZ() {
-        return minZ;
-    }
-    /**
-     * @return the maxZZ
-     */
-    public int getMaxZ() {
-        return maxZ;
-    }
-
-    public int getArea() {
-        // Get interior area
-        return (maxX - minX) * (maxZ - minZ);
-    }
-
     /**
      * @return the floor
      */
diff --git a/src/main/java/world/bentobox/greenhouses/listeners/GreenhouseEvents.java b/src/main/java/world/bentobox/greenhouses/listeners/GreenhouseEvents.java
index 702eaab..410aedd 100644
--- a/src/main/java/world/bentobox/greenhouses/listeners/GreenhouseEvents.java
+++ b/src/main/java/world/bentobox/greenhouses/listeners/GreenhouseEvents.java
@@ -98,12 +98,12 @@ public class GreenhouseEvents implements Listener {
         // from is a greenhouse
         if (from.isPresent() && !to.isPresent()) {
             // Exiting
-            user.sendMessage("greenhouses.event.leaving", "BIOME", from.get().getBiomeRecipe().getFriendlyName());
+            user.sendMessage("greenhouses.event.leaving", BIOME, from.get().getBiomeRecipe().getFriendlyName());
             return;
         }
         if (!from.isPresent()) {
             // Entering
-            user.sendMessage("greenhouses.event.entering", "BIOME", to.get().getBiomeRecipe().getFriendlyName());
+            user.sendMessage("greenhouses.event.entering", BIOME, to.get().getBiomeRecipe().getFriendlyName());
         }
 
     }
@@ -133,7 +133,7 @@ public class GreenhouseEvents implements Listener {
                     || e.getBlock().getLocation().getBlockZ() == (int)g.getBoundingBox().getMinZ()
                     || e.getBlock().getLocation().getBlockZ() == (int)g.getBoundingBox().getMaxZ() - 1
                     ) {
-                user.sendMessage("greenhouses.event.broke", "BIOME", Util.prettifyText(g.getOriginalBiome().name()));
+                user.sendMessage("greenhouses.event.broke", BIOME, Util.prettifyText(g.getOriginalBiome().name()));
                 plugin.getManager().removeGreenhouse(g);
             }
         });
diff --git a/src/main/java/world/bentobox/greenhouses/ui/panel/Panel.java b/src/main/java/world/bentobox/greenhouses/ui/panel/Panel.java
index a024f32..0eb7343 100644
--- a/src/main/java/world/bentobox/greenhouses/ui/panel/Panel.java
+++ b/src/main/java/world/bentobox/greenhouses/ui/panel/Panel.java
@@ -12,6 +12,7 @@ import world.bentobox.greenhouses.greenhouse.BiomeRecipe;
 
 public class Panel {
 
+    private static final String COVERAGE = "[coverage]";
     private Greenhouses addon;
 
     public Panel(Greenhouses addon) {
@@ -41,13 +42,13 @@ public class Panel {
             br.getRecipeBlocks().forEach(b -> d.add(user.getTranslation("greenhouses.recipe.blockscolor") + b));
         }
         if (br.getWaterCoverage() > 0) {
-            d.add(user.getTranslation("greenhouses.recipe.watermustbe", "[coverage]", String.valueOf(br.getWaterCoverage())));
+            d.add(user.getTranslation("greenhouses.recipe.watermustbe", COVERAGE, String.valueOf(br.getWaterCoverage())));
         }
         if (br.getLavaCoverage() > 0) {
-            d.add(user.getTranslation("greenhouses.recipe.lavamustbe", "[coverage]", String.valueOf(br.getLavaCoverage())));
+            d.add(user.getTranslation("greenhouses.recipe.lavamustbe", COVERAGE, String.valueOf(br.getLavaCoverage())));
         }
         if (br.getIceCoverage() > 0) {
-            d.add(user.getTranslation("greenhouses.recipe.icemustbe", "[coverage]", String.valueOf(br.getIceCoverage())));
+            d.add(user.getTranslation("greenhouses.recipe.icemustbe", COVERAGE, String.valueOf(br.getIceCoverage())));
         }
         if (br.getRecipeBlocks().isEmpty()) {
             d.add(user.getTranslation("greenhouses.recipe.nootherblocks"));