diff --git a/plugins/cmake/cmakebuilddirchooser.ui b/plugins/cmake/cmakebuilddirchooser.ui
--- a/plugins/cmake/cmakebuilddirchooser.ui
+++ b/plugins/cmake/cmakebuilddirchooser.ui
@@ -79,6 +79,12 @@
        <verstretch>0</verstretch>
       </sizepolicy>
      </property>
+     <property name="toolTip">
+      <string>The prefix under which the project will be installed. Leaving this empty will let CMake use its default install prefix.</string>
+     </property>
+     <property name="placeholderText">
+      <string>CMake's default install prefix</string>
+     </property>
     </widget>
    </item>
    <item row="4" column="0">
diff --git a/plugins/cmake/cmakeutils.h b/plugins/cmake/cmakeutils.h
--- a/plugins/cmake/cmakeutils.h
+++ b/plugins/cmake/cmakeutils.h
@@ -116,7 +116,8 @@
     KDEVCMAKECOMMON_EXPORT KDevelop::Path currentCMakeExecutable(KDevelop::IProject* project, int builddir = -1);
 
     /**
-     * @returns the current install dir for the given project or "/usr/local" as default value.
+     * @returns the current install dir for the given project or an empty string if none has been defined
+     * (in that case, whatever default CMake sets for the platform will be used.)
      */
     KDEVCMAKECOMMON_EXPORT KDevelop::Path currentInstallDir( KDevelop::IProject* project, int builddir = -1 );
     
diff --git a/plugins/cmake/cmakeutils.cpp b/plugins/cmake/cmakeutils.cpp
--- a/plugins/cmake/cmakeutils.cpp
+++ b/plugins/cmake/cmakeutils.cpp
@@ -359,13 +359,7 @@
 
 KDevelop::Path currentInstallDir( KDevelop::IProject* project, int builddir )
 {
-    const QString defaultInstallDir =
-#ifdef Q_OS_WIN
-        QStringLiteral("C:\\Program Files");
-#else
-        QStringLiteral("/usr/local");
-#endif
-    return KDevelop::Path(readBuildDirParameter( project, Config::Specific::cmakeInstallDirKey, defaultInstallDir, builddir ));
+    return KDevelop::Path(readBuildDirParameter( project, Config::Specific::cmakeInstallDirKey, QString(), builddir ));
 }
 
 QString projectRootRelative( KDevelop::IProject* project )