diff --git a/paper-slider.html b/paper-slider.html
index 263a793..341c547 100644
--- a/paper-slider.html
+++ b/paper-slider.html
@@ -91,7 +91,7 @@
         outline: none;
       }
         
-      :host-context([dir="rtl"]) #sliderContainer {
+      :host([_is-r-t-l]) #sliderContainer {
         -webkit-transform: scaleX(-1);
         transform: scaleX(-1);
       }
@@ -462,6 +462,11 @@
               return [];
           }
         },
+
+        _isRTL: {
+          type: Boolean,
+          reflectToAttribute: true,
+        },
       },
 
       observers: [
@@ -483,6 +488,10 @@
         'up pageup end': '_incrementKey'
       },
 
+      attached: function() {
+        this._isRTL = window.getComputedStyle(this)['direction'] === 'rtl';
+      },
+
       /**
        * Increases value by `step` but not above `max`.
        * @method increment
@@ -689,13 +698,6 @@
         });
       },
 
-      get _isRTL() {
-        if (this.__isRTL === undefined) {
-          this.__isRTL = window.getComputedStyle(this)['direction'] === 'rtl';
-        }
-        return this.__isRTL;
-      },
-
       _leftKey: function(event) {
         if (this._isRTL)
           this._incrementKey(event);
diff --git a/test/rtl.html b/test/rtl.html
index b927ae2..3467213 100644
--- a/test/rtl.html
+++ b/test/rtl.html
@@ -28,6 +28,20 @@
     </template>
   </test-fixture>
 
+  <test-fixture id="cssDirectionRtl">
+    <template>
+      <paper-slider value="50" style="direction: rtl;"></paper-slider>
+    </template>
+  </test-fixture>
+
+  <test-fixture id="nestedDirAttributes">
+    <template>
+      <div dir="rtl">
+        <paper-slider value="50" dir="ltr"></paper-slider>
+      </div>
+    </template>
+  </test-fixture>
+
   <script>
     suite('<paper-slider>', function() {
       var slider;
@@ -99,6 +113,14 @@
         assert.equal(oldValue - slider.step, slider.value);
         assert.isTrue(down.defaultPrevented);
       });
+
+      test('css direction works', function() {
+        assert.isTrue(fixture('cssDirectionRtl')._isRTL);
+      });
+
+      test('nested [dir] attributes work', function() {
+        assert.isFalse(fixture('nestedDirAttributes').firstElementChild._isRTL);
+      });
     });
 
   </script>