diff --git a/readthedocs/doc_builder/backends/mkdocs.py b/readthedocs/doc_builder/backends/mkdocs.py
index 97fa45e59fd..412d34dc22a 100644
--- a/readthedocs/doc_builder/backends/mkdocs.py
+++ b/readthedocs/doc_builder/backends/mkdocs.py
@@ -191,4 +191,4 @@ def build(self):
             user_config,
             open(os.path.join(self.root_path, 'mkdocs.yml'), 'w')
         )
-        super(MkdocsJSON, self).build()
+        return super(MkdocsJSON, self).build()