Columns and headers

Hi guys,

I’ve set up columns on a page.
[one_third] text here [/one_third]

I’ve done three of them and they display fine but when I add a header below.
eg <h2>New header</h2>
the beginning of the header starts to the right of third column and continues on the next line.

How do I get the whole header to start on a new line?

Annabelle