diff --git a/src/DDLWrapper/Db/Table.php b/src/DDLWrapper/Db/Table.php
index ef3eb1d..b94f47b 100644
--- a/src/DDLWrapper/Db/Table.php
+++ b/src/DDLWrapper/Db/Table.php
@@ -587,7 +587,7 @@ class Table
     public function addSoftDelete($deletedAtColumnName = 'deleted_at'){
     	$deletedAtColumnName = is_null($deletedAtColumnName) ? 'deleted_at' : $deletedAtColumnName;
         $this->addColumn($deletedAtColumnName, 'timestamp', array(
-            'default' => 'null',
+            'default' => null,
             'null'    => true,
         ));
         return $this;