diff --git a/adaptiveumbrella/wham2d.py b/adaptiveumbrella/wham2d.py
index 8b6379f..96e6e1b 100644
--- a/adaptiveumbrella/wham2d.py
+++ b/adaptiveumbrella/wham2d.py
@@ -74,7 +74,7 @@ class WHAM2DRunner(UmbrellaRunner):
 
 
         borders = self.get_wham_borders()
-        cmd = "{exec} Px={px} {min_x} {max_x} {frames_x} Py={py} {min_y} {max_y} {frames_y} {tol} {temperature} 0 {metafile} {outfile} 0".format(
+        cmd = "{exec} Px={px} {min_x} {max_x} {frames_x} Py={py} {min_y} {max_y} {frames_y} {tol} {temperature} 0 {metafile} {outfile} {mask}".format(
             exec=self.WHAM_EXEC,
             px=self.whamconfig['Px'],
             min_x=borders[0],
@@ -87,7 +87,8 @@ class WHAM2DRunner(UmbrellaRunner):
             tol=self.whamconfig['tolerance'],
             temperature=self.whamconfig['temperature'],
             metafile=metafile_path,
-            outfile=output_path
+            outfile=output_path,
+            mask=1
         )
         if self.verbose:
             print(cmd)