diff --git a/dumux/discretization/facecentered/staggered/elementvolumevariables.hh b/dumux/discretization/facecentered/staggered/elementvolumevariables.hh
index 8a349bfb2200073945870882153fbd61b81dc757..0a12cf6380d0585427bd0f4521c71cb72d89de2a 100644
--- a/dumux/discretization/facecentered/staggered/elementvolumevariables.hh
+++ b/dumux/discretization/facecentered/staggered/elementvolumevariables.hh
@@ -96,8 +96,9 @@ public:
             return;
 
         clear_();
-        boundaryVolVarIndices_.reserve(fvGeometry.gridGeometry().numBoundaryScv());
-        boundaryVolumeVariables_.reserve(fvGeometry.gridGeometry().numBoundaryScv());
+        // upper bound of size is the number of all scvfs minus frontal scvfs
+        boundaryVolVarIndices_.reserve(fvGeometry.numScvf()-element.subEntities(1));
+        boundaryVolumeVariables_.reserve(fvGeometry.numScvf()-element.subEntities(1));
 
         for (const auto& scvf : scvfs(fvGeometry))
         {