diff --git a/ges/ges-formatter.h b/ges/ges-formatter.h
index df76e14788..e57b28db6c 100644
--- a/ges/ges-formatter.h
+++ b/ges/ges-formatter.h
@@ -59,7 +59,7 @@ struct _GESFormatter {
   GESTimeline *timeline;
 
   /* Padding for API extension */
-  gpointer _ges_reserved[GES_PADDING - 1];
+  gpointer _ges_reserved[GES_PADDING];
 };
 
 typedef gboolean (*GESFormatterCanLoadURIMethod) (const gchar * uri, GError **error);
diff --git a/ges/ges-timeline-object.h b/ges/ges-timeline-object.h
index 5c752cd311..89dede4f7c 100644
--- a/ges/ges-timeline-object.h
+++ b/ges/ges-timeline-object.h
@@ -172,7 +172,7 @@ struct _GESTimelineObject {
   guint64 fullduration; /* Full usable duration of the object (-1: no duration) */
 
   /* Padding for API extension */
-  gpointer _ges_reserved[GES_PADDING];
+  gpointer _ges_reserved[GES_PADDING_LARGE];
 };
 
 /**
@@ -216,7 +216,7 @@ struct _GESTimelineObjectClass {
 
   /*< private >*/
   /* Padding for API extension */
-  gpointer _ges_reserved[GES_PADDING - 4];
+  gpointer _ges_reserved[GES_PADDING_LARGE];
 };
 
 GType ges_timeline_object_get_type          (void);
diff --git a/ges/ges-track-object.h b/ges/ges-track-object.h
index 307a9a9ce8..60b25a7712 100644
--- a/ges/ges-track-object.h
+++ b/ges/ges-track-object.h
@@ -90,7 +90,7 @@ struct _GESTrackObject {
   GESTrackObjectPrivate *priv;
 
   /* Padding for API extension */
-  gpointer _ges_reserved[GES_PADDING];
+  gpointer _ges_reserved[GES_PADDING_LARGE];
 };
 
 /**
@@ -141,7 +141,7 @@ struct _GESTrackObjectClass {
               guint *n_properties);
   /*< private >*/
   /* Padding for API extension */
-  gpointer _ges_reserved[GES_PADDING - 2];
+  gpointer _ges_reserved[GES_PADDING_LARGE];
 };
 
 GType ges_track_object_get_type               (void);
diff --git a/ges/ges-types.h b/ges/ges-types.h
index 455c457afa..a724cbb400 100644
--- a/ges/ges-types.h
+++ b/ges/ges-types.h
@@ -22,7 +22,10 @@
 #define __GES_TYPES_H__
 
 /* Padding */
-#define GES_PADDING		4
+#define GES_PADDING         4
+
+/* padding for very extensible base classes */
+#define GES_PADDING_LARGE   20
 
 /* Type definitions */