The foundation framework allows nested
<div class="row"> get the width of the page but
you can put another
<div class="row">into it
which is going a smaller 12-columns-max-width.
You can check the docs related to this feature here : http://foundation.zurb.com/docs/components/grid.html
Are you sure the row you paste in the question is the first one
in your HTML code ? If it is, can you paste a link for a demo of
your code please?
If i understand it rights, it pretty simple to do with CSS :