diff --git a/dist/sticky-kit.js b/dist/sticky-kit.js
index 9597bd0..a848e93 100644
--- a/dist/sticky-kit.js
+++ b/dist/sticky-kit.js
@@ -106,7 +106,8 @@
             height: height,
             display: elm.css("display"),
             "vertical-align": elm.css("vertical-align"),
-            "float": el_float
+            "float": el_float,
+            "z-index": -1
           });
         }
         if (restore) {
diff --git a/sticky-kit.coffee b/sticky-kit.coffee
index 73c3b13..5a6a4a3 100644
--- a/sticky-kit.coffee
+++ b/sticky-kit.coffee
@@ -182,7 +182,7 @@ $.fn.stick_in_parent = (opts={}) ->
             fixed = true
             css = {
               position: "fixed"
-              top: offset
+              top: offset + "px"
             }
 
             css.width = if elm.css("box-sizing") == "border-box"