diff --git a/yamldifftool.py b/yamldifftool.py
index 92ff463..05bbf8e 100644
--- a/yamldifftool.py
+++ b/yamldifftool.py
@@ -16,9 +16,8 @@ def traverse_and_set(user_provided, root_diff, path):
 def filter_defaults(base, user_provided, root_diff, path=[], strict=False):
     if type(user_provided) is dict:
         for key in user_provided.keys():
-            if base is None:
-                continue
-            if type(base) is str:
+            if base is None or type(base) is str:
+                traverse_and_set(user_provided.get(key), root_diff, path + [key])
                 continue
             if not strict and key not in base.keys():
                 traverse_and_set(user_provided.get(key), root_diff, path + [key])