diff --git a/src/sand-wedge-data/mygrid.cc b/src/sand-wedge-data/mygrid.cc
index b2e9565312f25e553ed0f6fca80469ccabf1f799..61ecdada7b9b5b61b1721aec179ce4ee101a1d56 100644
--- a/src/sand-wedge-data/mygrid.cc
+++ b/src/sand-wedge-data/mygrid.cc
@@ -208,11 +208,11 @@ MyFaces<GridView>::MyFaces(GridView const &gridView)
   });
 #if DIM == 3
   front.insertFacesByProperty([&](typename GridView::Intersection const &in) {
-    return isClose(-MyGeometry::depth / 2.0, in.geometry().center()[2]);
+    return isClose(MyGeometry::depth / 2.0, in.geometry().center()[2]);
   });
 
   back.insertFacesByProperty([&](typename GridView::Intersection const &in) {
-    return isClose(MyGeometry::depth / 2.0, in.geometry().center()[2]);
+    return isClose(-MyGeometry::depth / 2.0, in.geometry().center()[2]);
   });
 #endif