Rewrite rules stop directory index.html

Hi- We have some pages that live outside of Perch. When I visit the directory, /2019TYP it does not pull up the index.html page by default. I temporarily removed the rewrite rules in the .htaccess file and I was once again able to get the index.html page to load when visiting just the directory name. Any ideas on how to set it up so that if I visit a directory created outside of Perch, it will automatically load the index.html page.