A retractable screen door is mounted on the inside of your house by using the half inch edge around the three sides of your door and then we add one of the many sill adapters to the bottom to follow the same line as the half inch edge. If you are wondering how we install a retractable screen door on such a small edge you are not alone and this is a common and good question. We only use screws at the top and bottom of the screen door to secure it. The aluminun is so thick that the screen door housing unit stays firm during use. If you don't have a small edge around your door opening, we can install the retractable screen door housing unit next to your molding. The picture should give you a good idea of how the installation would turn out.