This is not recommended practice as you end up with all your app code, config items etc accessible from the outside.
So you are saying that all 25 sites are on the same domain but in different sub folders?
If so, I would have a directory structure like
\var\site1
\var\site2
\var\www\site1
\var\www\site2
in the var\site1 folder you have the Laravel installation with your app
in the var\www\site1 folder have the contents of the site1 public folder. In this folder, change the index.php to bootstrap the correct installation.
no, actually what I would do is have each on a different sub domain, hosted on different servers.