diff --git a/lxc-build b/lxc-build
index bdfc682..c8b0b00 100755
--- a/lxc-build
+++ b/lxc-build
@@ -117,7 +117,7 @@ class LXCImage:
         self.rebuild_config()
 
     def copy_files(self, src, dst):
-        src = os.path.join(build_dir, src)
+        src = os.path.join(self.build_dir, src)
         dst = os.path.join(self.layers[-1], dst)
         copy_tree(src, dst)