diff --git a/src/plugins/projectexplorer/buildconfiguration.cpp b/src/plugins/projectexplorer/buildconfiguration.cpp
index 6196e988e30a2c10a10b56e0f59af750c78452ad..06364fb0540f02dc360d9f5d60b7882b2e4df4c4 100644
--- a/src/plugins/projectexplorer/buildconfiguration.cpp
+++ b/src/plugins/projectexplorer/buildconfiguration.cpp
@@ -29,7 +29,7 @@
 
 #include "buildconfiguration.h"
 
-using namespace ProjectExplorer;
+using namespace ProjectExplorer::Internal;
 
 BuildConfiguration::BuildConfiguration(const QString &name)
     : m_name(name)
diff --git a/src/plugins/projectexplorer/buildconfiguration.h b/src/plugins/projectexplorer/buildconfiguration.h
index c061b33808f45b577a88f550876e54d2440f87cd..dbb200896e670f607e5117770b7197f228ea56c0 100644
--- a/src/plugins/projectexplorer/buildconfiguration.h
+++ b/src/plugins/projectexplorer/buildconfiguration.h
@@ -35,7 +35,7 @@
 #include <QtCore/QHash>
 
 namespace ProjectExplorer {
-
+namespace Internal {
 class BuildConfiguration
 {
 public:
@@ -55,7 +55,7 @@ private:
     QHash<QString, QVariant> m_values;
     QString m_name;
 };
-
+}
 } // namespace ProjectExplorer
 
 #endif // BUILDCONFIGURATION_H
diff --git a/src/plugins/projectexplorer/buildstep.cpp b/src/plugins/projectexplorer/buildstep.cpp
index 8141861b70ff8018a1bd66856659bd6aaacee85f..3199cc3e489eedc775010079e083a5ce332a969a 100644
--- a/src/plugins/projectexplorer/buildstep.cpp
+++ b/src/plugins/projectexplorer/buildstep.cpp
@@ -32,7 +32,8 @@
 
 #include <utils/qtcassert.h>
 
-namespace ProjectExplorer {
+using namespace ProjectExplorer;
+using namespace ProjectExplorer::Internal;
 
 BuildStep::BuildStep(Project * pro)
     : m_project(pro)
@@ -141,5 +142,3 @@ IBuildStepFactory::~IBuildStepFactory()
 {
 
 }
-
-} // namespace ProjectExplorer
diff --git a/src/plugins/projectexplorer/buildstep.h b/src/plugins/projectexplorer/buildstep.h
index e9b4267d8329c583f9572367fe1bf5376bf1ac60..9fb5a3cdc82ea1ace310de8d198cef45ba852b83 100644
--- a/src/plugins/projectexplorer/buildstep.h
+++ b/src/plugins/projectexplorer/buildstep.h
@@ -39,7 +39,9 @@
 
 namespace ProjectExplorer {
 
+namespace Internal {
 class BuildConfiguration;
+}
 
 /*
 // BuildSteps are the primary way plugin developers can customize
@@ -132,14 +134,14 @@ Q_SIGNALS:
     void displayNameChanged(BuildStep *, const QString &displayName);
 
 private:
-    QList<BuildConfiguration *> buildConfigurations();
+    QList<Internal::BuildConfiguration *> buildConfigurations();
     void addBuildConfiguration(const QString & name);
     void removeBuildConfiguration(const QString & name);
-    BuildConfiguration *getBuildConfiguration(const QString & name) const;
+    Internal::BuildConfiguration *getBuildConfiguration(const QString & name) const;
     void copyBuildConfiguration(const QString &source, const QString &dest);
 
-    QList<BuildConfiguration *> m_buildConfigurations;
-    BuildConfiguration *m_configuration;
+    QList<Internal::BuildConfiguration *> m_buildConfigurations;
+    Internal::BuildConfiguration *m_configuration;
     Project *m_project;
 };
 
diff --git a/src/plugins/projectexplorer/project.cpp b/src/plugins/projectexplorer/project.cpp
index 3f83f4763e75a922fe13c783c47ec6c0b9c6f854..a36c01235ed9795f4e7bae2914f64d22a8870fb8 100644
--- a/src/plugins/projectexplorer/project.cpp
+++ b/src/plugins/projectexplorer/project.cpp
@@ -42,6 +42,7 @@
 #include <QtCore/QTextCodec>
 
 using namespace ProjectExplorer;
+using namespace ProjectExplorer::Internal;
 
 Project::Project()
     : m_activeRunConfiguration(0),
diff --git a/src/plugins/projectexplorer/project.h b/src/plugins/projectexplorer/project.h
index bfe5872e781a1e3747b246a181fcb81b27c01537..b4be7fa0c1c4257dec55281cf0197f916c358448 100644
--- a/src/plugins/projectexplorer/project.h
+++ b/src/plugins/projectexplorer/project.h
@@ -165,13 +165,13 @@ protected:
     virtual void restoreSettingsImpl(PersistentSettingsReader &reader);
 
 private:
-    BuildConfiguration *getBuildConfiguration(const QString & name) const;
+    Internal::BuildConfiguration *getBuildConfiguration(const QString & name) const;
 
     QList<BuildStep *> m_buildSteps;
     QList<BuildStep *> m_cleanSteps;
     QStringList m_buildConfigurations;
     QMap<QString, QVariant> m_values;
-    QList<BuildConfiguration *> m_buildConfigurationValues;
+    QList<Internal::BuildConfiguration *> m_buildConfigurationValues;
     QString m_activeBuildConfiguration;
     QList<QSharedPointer<RunConfiguration> > m_runConfigurations;
     QSharedPointer<RunConfiguration> m_activeRunConfiguration;