diff --git a/lib/Horde/Date/Recurrence.php b/lib/Horde/Date/Recurrence.php
index 6208170..275a951 100644
--- a/lib/Horde/Date/Recurrence.php
+++ b/lib/Horde/Date/Recurrence.php
@@ -177,12 +177,12 @@ public function reset()
 
     public function recurOnDay($dayMask)
     {
-        return ($this->modern->getDayMask() & $dayMask);
+        return ($this->modern->getDayMask() & (int) $dayMask);
     }
 
     public function setRecurOnDay($dayMask)
     {
-        $this->modern->setDayMask($dayMask);
+        $this->modern->setDayMask((int) $dayMask);
     }
 
     public function getRecurOnDays()