diff --git a/untiler/scripts/tile_utils.py b/untiler/scripts/tile_utils.py
index 486f1ea..d43e1ec 100644
--- a/untiler/scripts/tile_utils.py
+++ b/untiler/scripts/tile_utils.py
@@ -65,7 +65,7 @@ def get_unique_tiles(self, data):
         return uniq
 
 
-    def get_zoom_tiles(self, subTiles, superTiles, tile, tilefloor=16):
+    def get_zoom_tiles(self, subTiles, superTiles, tile, tilefloor=15):
         """
         Given:
         (1) an array of [z, x, y] sub tiles at multiple zooms;