diff --git a/src/Claims/Factory.php b/src/Claims/Factory.php
index 9e823d90..808a607e 100644
--- a/src/Claims/Factory.php
+++ b/src/Claims/Factory.php
@@ -214,7 +214,7 @@ public function getTTL()
      */
     public function setLeeway($leeway)
     {
-        $this->leeway = $leeway;
+        $this->leeway = (int) $leeway;
 
         return $this;
     }