Rollformed aluminum screen doors are the type you might see for sale at your local large home improvement center. They are typically made of very thin aluminum, which is rolled into a rectangular shape for strength. These doors usually feature an adjustable shoe so you can adjust the height of the door to match your patio door opening. These doors are ok if you need a door to get your house sold but they are not something to use if you expect to your patio screen door replacement to last for many years.
Extruded aluminum screen doors are what you need to look for when doing a screen door replacement. These are often sold by glass shops and window suppliers. They need to be custom ordered so you have to carefully measure your patio door opening so that they fit properly. An extruded aluminum screen door is much much stronger than the cheaper rollformed door.
Buy an extruded aluminum door with ball bearing steelrollers, these make the door operate much more smoothly and give you years of good service. Extruded aluminum doors are not indestructible but theydo last if cared for properly.If you want to purchase a patio screen door replacement, here are instructions for assembling a "knocked down"screen door. A knocked down screen door is simply a screen door that is shipped to you in pieces for you to assemble. These instructions applyto my own screen doors but most doors are assembled this way and so the instructions will still apply for a number of different manufacturers. If you would like to purchase one of my doors, look for the instructionsat the bottom of the page. | 
