diff --git a/src/dynamicMesh/polyMeshAdder/polyMeshAdder.C b/src/dynamicMesh/polyMeshAdder/polyMeshAdder.C
index 45c96fc385..455769d7d2 100644
--- a/src/dynamicMesh/polyMeshAdder/polyMeshAdder.C
+++ b/src/dynamicMesh/polyMeshAdder/polyMeshAdder.C
@@ -69,7 +69,7 @@ void Foam::polyMeshAdder::append
     DynamicList<label>& dynLst
 )
 {
-    dynLst.setSize(dynLst.size() + lst.size());
+    dynLst.setCapacity(dynLst.size() + lst.size());
 
     forAll(lst, i)
     {