RewriteEngine  on

RewriteRule ^index.html$ index.php
RewriteRule ^realisations.html$ realisations.php
RewriteRule ^roofing-services-montreal/roofing.html$ roofing.php
I'm new to mod_rewrite, and it's either my server doesn't support the module or I'm doing something wrong.
Should the code above work properly if uploaded to ?

Basically I'm trying to change specific .php pages to .html, and give some pages a fake sub-directory extension, will this work?
Thank you very much in advance.