diff --git a/commands/FBVisualizationCommands.py b/commands/FBVisualizationCommands.py
index 1f8c4d7..3948a31 100755
--- a/commands/FBVisualizationCommands.py
+++ b/commands/FBVisualizationCommands.py
@@ -100,8 +100,8 @@ def _showLayer(layer):
   layer = '(' + layer + ')'
   size = '((CGRect)[(id)' + layer + ' bounds]).size'
 
-  width = float(fb.evaluateExpression(size + '.width'))
-  height = float(fb.evaluateExpression(size + '.height'))
+  width = float(fb.evaluateExpression('(CGFloat)(' + size + '.width)'))
+  height = float(fb.evaluateExpression('(CGFloat)(' + size + '.height)'))
   if width == 0.0 or height == 0.0:
     print 'Nothing to see here - the size of this element is {} x {}.'.format(width, height)
     return