diff --git a/gtk2_ardour/export_dialog.cc b/gtk2_ardour/export_dialog.cc
index 5fe5a56205..e186f3712e 100644
--- a/gtk2_ardour/export_dialog.cc
+++ b/gtk2_ardour/export_dialog.cc
@@ -1019,12 +1019,12 @@ ExportDialog::start_export ()
 		string dir = session->export_dir();
 		string::size_type last_slash;
 		
-		if ((last_slash = dir.find_last_of ('/')) != string::npos && last_slash != 0) {
+		if ((last_slash = dir.find_last_of (G_DIR_SEPARATOR_S)) != string::npos && last_slash != 0) {
 			dir = dir.substr (0, last_slash+1);
 		}
 
 		if (!wants_dir()) {
-			dir = dir + "export.wav";
+			dir = dir + "export.wav"; // Glib::build_filename() ?
 		}
 		
 		file_entry.set_text (dir);
diff --git a/libs/ardour/audiofilesource.cc b/libs/ardour/audiofilesource.cc
index ba90026740..919e9587fe 100644
--- a/libs/ardour/audiofilesource.cc
+++ b/libs/ardour/audiofilesource.cc
@@ -222,13 +222,7 @@ AudioFileSource::find_broken_peakfile (ustring peak_path, ustring audio_path)
 ustring
 AudioFileSource::broken_peak_path (ustring audio_path)
 {
-	ustring res;
-
-	res = _session.peak_dir ();
-	res += PBD::basename_nosuffix (audio_path);
-	res += ".peak";
-
-	return res;
+	return Glib::build_filename(_session.peak_dir (), PBD::basename_nosuffix (audio_path) + ".peak");
 }
 
 ustring
diff --git a/libs/ardour/io.cc b/libs/ardour/io.cc
index 10b1e42328..ac5381b591 100644
--- a/libs/ardour/io.cc
+++ b/libs/ardour/io.cc
@@ -25,6 +25,7 @@
 
 #include <sigc++/bind.h>
 
+#include <glibmm.h>
 #include <glibmm/thread.h>
 
 #include <pbd/xml++.h>
@@ -1669,16 +1670,12 @@ IO::load_automation (string path)
 	float version;
 	LocaleGuard lg (X_("POSIX"));
 
-	fullpath = _session.automation_dir();
-	fullpath += path;
+	fullpath = Glib::build_filename(_session.automation_dir(), path);
 
 	in.open (fullpath.c_str());
 
 	if (!in) {
-		fullpath = _session.automation_dir();
-		fullpath += _session.snap_name();
-		fullpath += '-';
-		fullpath += path;
+		fullpath = Glib::build_filename(_session.automation_dir(), _session.snap_name() + '-' + path);
 
 		in.open (fullpath.c_str());
 
diff --git a/libs/ardour/panner.cc b/libs/ardour/panner.cc
index eb9547edff..db802b0921 100644
--- a/libs/ardour/panner.cc
+++ b/libs/ardour/panner.cc
@@ -1155,8 +1155,7 @@ Panner::set_state (const XMLNode& node)
 
 		/* automation path is relative */
 		
-		automation_path = _session.automation_dir();
-		automation_path += prop->value ();
+		automation_path = Glib::build_filename(_session.automation_dir(), prop->value ());
 	} 
 
 	return 0;
@@ -1324,11 +1323,8 @@ Panner::set_position (float xpos, float ypos, float zpos, StreamPanner& orig)
 void
 Panner::set_name (string str)
 {
-	automation_path = _session.automation_dir();
-	automation_path += _session.snap_name();
-	automation_path += "-pan-";
-	automation_path += legalize_for_path (str);
-	automation_path += ".automation";
+	automation_path = Glib::build_filename(_session.automation_dir(), 
+		_session.snap_name() + "-pan-" + legalize_for_path (str) + ".automation");
 }
 
 int
diff --git a/libs/ardour/redirect.cc b/libs/ardour/redirect.cc
index b1e631015f..afb166b8cb 100644
--- a/libs/ardour/redirect.cc
+++ b/libs/ardour/redirect.cc
@@ -26,6 +26,8 @@
 
 #include <sigc++/bind.h>
 
+#include <glibmm.h>
+
 #include <pbd/xml++.h>
 #include <pbd/enumwriter.h>
 
@@ -342,8 +344,7 @@ Redirect::load_automation (string path)
 	if (path[0] == '/') { // legacy
 		fullpath = path;
 	} else {
-		fullpath = _session.automation_dir();
-		fullpath += path;
+		fullpath = Glib::build_filename(_session.automation_dir(), path);
 	}
 	ifstream in (fullpath.c_str());
 
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index b11ed56a6e..2a10773d09 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -2970,13 +2970,7 @@ Session::source_by_path_and_channel (const Glib::ustring& path, uint16_t chn)
 Glib::ustring
 Session::peak_path (Glib::ustring base) const
 {
-	Glib::ustring res;
-	
-	res = peak_dir ();
-	res += base;
-	res += ".peak";
-
-	return res;
+	return Glib::build_filename(peak_dir (), base + ".peak");
 }
 
 string