Ah I see the problem.
Try adding this function:
add_filter( 'generate_site_title_output','tu_blog_h1_title' );
function tu_blog_h1_title() {
printf(
'<%1$s class="main-title" itemprop="headline">
<a href="%2$s" rel="home">
%3$s
</a>
</%1$s>',
( is_home() ) ? 'h1' : 'p',
esc_url( apply_filters( 'generate_site_title_href', home_url( '/' ) ) ),
get_bloginfo( 'name' )
);
}