Code for iThemes Builder to apply a layout to Timely’s All-in-One Event Calendar's events archive page, single event pages and calendar Page.

functions.php

function set_custom_layout( $layout_id ) {
    if ( is_post_type_archive('ai1ec_event') || is_singular('ai1ec_event') || is_page('calendar') )
            return '526e727b11aca';

    return $layout_id;
}
add_filter( 'builder_filter_current_layout', 'set_custom_layout' );