diff --git a/li.strolch.model/src/main/java/li/strolch/model/builder/ActionBuilder.java b/li.strolch.model/src/main/java/li/strolch/model/builder/ActionBuilder.java
index 5aeb35052..fcbff8f94 100644
--- a/li.strolch.model/src/main/java/li/strolch/model/builder/ActionBuilder.java
+++ b/li.strolch.model/src/main/java/li/strolch/model/builder/ActionBuilder.java
@@ -2,6 +2,7 @@ package li.strolch.model.builder;
 
 import li.strolch.model.PolicyContainer;
 import li.strolch.model.activity.Action;
+import li.strolch.utils.dbc.DBC;
 
 public class ActionBuilder extends PolicyContainerBuilder<ActionBuilder> implements ActivityElementBuilder {
 
@@ -14,12 +15,14 @@ public class ActionBuilder extends PolicyContainerBuilder<ActionBuilder> impleme
 		super(id, name, type);
 		this.builder = null;
 	}
+
 	public ActionBuilder(ActivityBuilder builder, String id, String name, String type) {
 		super(id, name, type);
 		this.builder = builder;
 	}
 
 	public ActivityBuilder endAction() {
+		DBC.PRE.assertNotNull("Can not end, as not part of a builder context!", this.builder);
 		return this.builder;
 	}
 
diff --git a/li.strolch.model/src/main/java/li/strolch/model/builder/ActivityBuilder.java b/li.strolch.model/src/main/java/li/strolch/model/builder/ActivityBuilder.java
index 886f1ac0f..79147292c 100644
--- a/li.strolch.model/src/main/java/li/strolch/model/builder/ActivityBuilder.java
+++ b/li.strolch.model/src/main/java/li/strolch/model/builder/ActivityBuilder.java
@@ -15,7 +15,16 @@ public class ActivityBuilder extends RootElementBuilder<ActivityBuilder> impleme
 
 	private final List<ActivityElementBuilder> builders;
 
-	public ActivityBuilder(StrolchElementBuilder builder, String id, String name, String type, TimeOrdering timeOrdering) {
+	public ActivityBuilder(String id, String name, String type, TimeOrdering timeOrdering) {
+		super(id, name, type);
+		this.builder = null;
+		this.parentBuilder = null;
+		this.timeOrdering = timeOrdering;
+		this.builders = new ArrayList<>();
+	}
+
+	public ActivityBuilder(StrolchElementBuilder builder, String id, String name, String type,
+			TimeOrdering timeOrdering) {
 		super(id, name, type);
 		this.builder = builder;
 		this.parentBuilder = null;
@@ -23,8 +32,8 @@ public class ActivityBuilder extends RootElementBuilder<ActivityBuilder> impleme
 		this.builders = new ArrayList<>();
 	}
 
-	public ActivityBuilder(StrolchElementBuilder builder, ActivityBuilder parentBuilder, String id, String name, String type,
-			TimeOrdering timeOrdering) {
+	public ActivityBuilder(StrolchElementBuilder builder, ActivityBuilder parentBuilder, String id, String name,
+			String type, TimeOrdering timeOrdering) {
 		super(id, name, type);
 		this.builder = builder;
 		this.parentBuilder = parentBuilder;
@@ -50,6 +59,7 @@ public class ActivityBuilder extends RootElementBuilder<ActivityBuilder> impleme
 	}
 
 	public StrolchElementBuilder endActivity() {
+		DBC.PRE.assertNotNull("Can not end, as not part of a builder context!", this.builder);
 		return this.builder;
 	}
 
diff --git a/li.strolch.model/src/main/java/li/strolch/model/builder/OrderBuilder.java b/li.strolch.model/src/main/java/li/strolch/model/builder/OrderBuilder.java
index a02f69ce3..0517f42db 100644
--- a/li.strolch.model/src/main/java/li/strolch/model/builder/OrderBuilder.java
+++ b/li.strolch.model/src/main/java/li/strolch/model/builder/OrderBuilder.java
@@ -2,18 +2,25 @@ package li.strolch.model.builder;
 
 import li.strolch.model.Order;
 import li.strolch.model.State;
+import li.strolch.utils.dbc.DBC;
 import li.strolch.utils.iso8601.ISO8601;
 
 public class OrderBuilder extends RootElementBuilder<OrderBuilder> {
 
 	private final StrolchElementBuilder builder;
 
+	public OrderBuilder(String id, String name, String type) {
+		super(id, name, type);
+		this.builder = null;
+	}
+
 	public OrderBuilder(StrolchElementBuilder builder, String id, String name, String type) {
 		super(id, name, type);
 		this.builder = builder;
 	}
 
 	public StrolchElementBuilder endOrder() {
+		DBC.PRE.assertNotNull("Can not end, as not part of a builder context!", this.builder);
 		return this.builder;
 	}
 
diff --git a/li.strolch.model/src/main/java/li/strolch/model/builder/ResourceBuilder.java b/li.strolch.model/src/main/java/li/strolch/model/builder/ResourceBuilder.java
index c49daa455..e7fa809ab 100644
--- a/li.strolch.model/src/main/java/li/strolch/model/builder/ResourceBuilder.java
+++ b/li.strolch.model/src/main/java/li/strolch/model/builder/ResourceBuilder.java
@@ -5,12 +5,19 @@ import java.util.List;
 
 import li.strolch.model.Resource;
 import li.strolch.model.builder.states.*;
+import li.strolch.utils.dbc.DBC;
 
 public class ResourceBuilder extends RootElementBuilder<ResourceBuilder> {
 
 	private final StrolchElementBuilder builder;
 	private final List<TimedStateBuilder<?>> timedStates;
 
+	public ResourceBuilder(String id, String name, String type) {
+		super(id, name, type);
+		this.builder = null;
+		this.timedStates = new ArrayList<>();
+	}
+
 	public ResourceBuilder(StrolchElementBuilder builder, String id, String name, String type) {
 		super(id, name, type);
 		this.builder = builder;
@@ -54,6 +61,7 @@ public class ResourceBuilder extends RootElementBuilder<ResourceBuilder> {
 	}
 
 	public StrolchElementBuilder endResource() {
+		DBC.PRE.assertNotNull("Can not end, as not part of a builder context!", this.builder);
 		return this.builder;
 	}