diff --git a/src/builder-source-dir.c b/src/builder-source-dir.c
index 671c7be6..0bba99bb 100644
--- a/src/builder-source-dir.c
+++ b/src/builder-source-dir.c
@@ -37,6 +37,7 @@ struct BuilderSourceDir
   BuilderSource parent;
 
   char         *path;
+  char         **hash_command;
   char        **skip;
 };
 
@@ -51,6 +52,7 @@ enum {
   PROP_0,
   PROP_PATH,
   PROP_SKIP,
+  PROP_DIR_HASH_CMD,
   LAST_PROP
 };
 
@@ -75,6 +77,10 @@ builder_source_dir_get_property (GObject    *object,
 
   switch (prop_id)
     {
+    case PROP_DIR_HASH_CMD:
+      g_value_set_boxed(value, self->dir_hash_cmd;
+      break;
+
     case PROP_PATH:
       g_value_set_string (value, self->path);
       break;
@@ -99,6 +105,12 @@ builder_source_dir_set_property (GObject      *object,
 
   switch (prop_id)
     {
+    case PROP_DIR_HASH_CMD:
+      tmp = self->dir_hash_cmd;
+      self->dir_hash_cmd = g_strdupv (g_value_get_boxed (value));
+      g_strfreev (tmp);
+      break;
+
     case PROP_PATH:
       g_free (self->path);
       self->path = g_value_dup_string (value);
@@ -271,8 +283,13 @@ builder_source_dir_checksum (BuilderSource  *source,
                               BuilderCache   *cache,
                               BuilderContext *context)
 {
-  /* We can't realistically checksum a directory, so always rebuild */
-  builder_cache_checksum_random (cache);
+  if (source.dir_hash_cmd) {
+    call_me(cache);
+  } else {
+    /* Checksumming a directory is a non-trivial pursuit. We currently opt to not integrate into flatpak directly
+       and rather always rebuild */
+    builder_cache_checksum_random (cache);
+  }
 }
 
 static void
@@ -292,6 +309,14 @@ builder_source_dir_class_init (BuilderSourceDirClass *klass)
   source_class->update = builder_source_dir_update;
   source_class->checksum = builder_source_dir_checksum;
 
+  g_object_class_install_property (object_class,
+                                   PROP_DIR_HASH_CMD,
+                                   g_param_spec_boxed ("dir_hash_cmd",
+                                                       "",
+                                                       "",
+                                                       G_TYPE_STRV,
+                                                       G_PARAM_READWRITE));
+
   g_object_class_install_property (object_class,
                                    PROP_PATH,
                                    g_param_spec_string ("path",