Custom Post Type using single.php is looking for a template that doesn’t exist

Without seeing more code, on the surface it looks like a typo somewhere because the {$posttype} would be tall_homes.

You could try putting an override function in your theme’s functions.php file though that should get around this:

function tall_homes_override( $template ) {
    global $wp_query;
    $post_type = get_query_var( 'post_type' );

    if ( $wp_query->is_single && $post_type == 'tall_homes' ) {
        return locate_template( 'single.php' );
    }
    return $template
}
add_filter( 'template_include', 'tall_homes_override' );

What this should do is that when WordPress goes to look for what template to use, it will test and see if this is a single post and what the post_type is. If it is single and the post_type is tall_homes then it will set it to use single.php instead.