diff --git a/game1_input.txt b/game1_input.txt
index b712047..191847f 100644
--- a/game1_input.txt
+++ b/game1_input.txt
@@ -117,6 +117,8 @@ list-resources
 build?
 build steamboat
 build fireplace
+build fireplace
+build axe
 build axe
 list-buildings
 build steamboat
diff --git a/game1_output.txt b/game1_output.txt
index b55ec75..82961c8 100644
--- a/game1_output.txt
+++ b/game1_output.txt
@@ -107,7 +107,10 @@ shack
 steamboat
 Error, need fireplace to build
 OK
+Error, already built
 OK
+OK
+axe
 axe
 fireplace
 OK
diff --git a/src/edu/kit/informatik/model/CardGame.java b/src/edu/kit/informatik/model/CardGame.java
index b584cb5..6892485 100644
--- a/src/edu/kit/informatik/model/CardGame.java
+++ b/src/edu/kit/informatik/model/CardGame.java
@@ -124,6 +124,8 @@ public class CardGame {
             throw new InvalidInputException("can not build item");
         } else if (item.requiresFireplace() && !items.contains(FIREPLACE)) {
             throw new InvalidInputException("need fireplace to build");
+        } else if (items.contains(item) && !item.canBeBuiltMultipleTimes()) {
+            throw new InvalidInputException("already built");
         } else if (canBuild(item)) {
             // remove used resources
             for (Card resource : item.resourcesNeeded()) {
diff --git a/src/edu/kit/informatik/model/Item.java b/src/edu/kit/informatik/model/Item.java
index 336b17f..0351653 100644
--- a/src/edu/kit/informatik/model/Item.java
+++ b/src/edu/kit/informatik/model/Item.java
@@ -41,6 +41,10 @@ public enum Item {
         return this.equals(STEAMBOAT) || this.equals(BALLOON);
     }
 
+    public boolean canBeBuiltMultipleTimes() {
+        return this.equals(AXE) || this.equals(CLUB);
+    }
+
     public static Item parse(String input) {
         switch (input) {
             case "axe":