I have HTTP Redirect pointing to HTTPS but people can still access using .com/ - do I need to use URL Rewrite?

Hello! I have a site that I just added an HTTP Redirect to.

Site is:

http://site1.example.com/app1

I want users to be able to type:

http://site1.example.com

and get redirected to:

https://site1.example.com/app1

I set up an HTTP redirect to the https site and it works when I put in http://site1.example.com

However, if the users type http://site1.example.com/app1 it still takes them to the http site.

What else do I need to do to make sure they can no longer access the port 80 site? 

I tried redirecting the /app1 site to https://site1.example.com/app1 but that breaks the application.

So do I need to use URL Rewrite? I was told that the HTTP Redirect is better to send HTTP traffic to HTTPS. Really I'd like to turn off the port 80 site completely but Business wants them to be able to type site1.example.com and get tohttps://site1.example.com/app1 so I'm not sure if I can turn off that http site.

Thank you for the help!