How do you configure a CodeIgniter application in order to have one directory which will just serve some static (not MVC) html?

I wish to handle some existing links, as:

http://mysite/contactform/contact.html?queryvars

Anything within the /contactform directory including sub-sites (that is some css, js, images,etc) shouldn't feel the CodeIgniter pipeline. What's the easiest method to handle that? (I'm ordinarily a Home windows dev, so speak gradually)

I decipher it needs to be completed in the rewrite config?

routes.php is extremely fundamental:

$route['default_controller'] = "home";

rewrite rules from .htaccess:

# you probably want www.example.com to forward to example.com -- shorter URLs are sexier.
#   no-www.org/faq.php?q=class_b
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www\.(.+)$ [NC]
RewriteRule ^(.*)$ http://%1/$1 [R=301,L]

RewriteEngine on
RewriteCond $1 !^(index\.php|contact\.php|images|css|js|video|robots\.txt)
RewriteRule ^(.*)$ index.php/$1 [L]

Modify your .htaccess like so:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^www\.(.+)$ [NC]
RewriteRule ^(.*)$ http://%1/$1 [R=301,L]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L]

RewriteCond %{REQUEST_FILENAME} !-f informs mod_rewrite disregard the url whether it's a real file, and RewriteCond %{REQUEST_FILENAME} !-d informs it to disregard it whether it's a directory.