How to concatenate several MvcHtmlString instances

I have some doubts about how to concatenate MvcHtmlString instances because of this information found in MSDN :

MvcHtmlString Class Represents an HTML-encoded string that should not be encoded again

Do I risk that strings are HTML-encoded twice when using code like this:

var label = Html.LabelFor(model => model.Email);
var textbox = Html.TextBoxFor(model => model.Email);
var validation = Html.ValidationMessageFor(model => model.Email);

var result = MvcHtmlString.Create(
  label.ToString() + textbox.ToString() + validation.ToString());

(note: this is supposed to go into an HtmlHelper extension method to reduce code-duplication in views).