diff --git a/src/XmlConstructor.php b/src/XmlConstructor.php
index c87c3cf..ea3ea51 100644
--- a/src/XmlConstructor.php
+++ b/src/XmlConstructor.php
@@ -161,12 +161,12 @@ public function toOutput()
             throw new RuntimeException('The constructor is closed. You have to create new one to flush its again.');
         }
 
+        $this->flushed = true;
+
         if ($this->hasDocumentStart) {
             $this->document->endDocument();
         }
 
-        $this->flushed = true;
-
         return $this->document->outputMemory();
     }