Some customers choose to lay the door on top of the siding and other recess it into the siding for visual factors. The main point would be to make certain that everything is properly sealed up. Do Check it Out have wall pet doors with aluminum tunnels? Yes, Hale, and Endura Flap all provide tunnels made of aluminum.
What if there is a ridge or shelf that is directly above where the in-wall doggie door will be? The ridge or shelf might get in the way of a top-loading locking cover. Hale provides a side loading locking cover. What does it indicate to "frame out" a wall? A wall setup family pet door need to always consist of a tunnel through the dog door wall.
As a secondary concern, the tunnel supplies the family pet with steady footing. There are 2 ways to achieve this tunnel. The very first and easiest is to purchase a "self-framing" wall install pet door. This kind of animal door will be supplied with its own tunnel which is usually changed by cutting to fit the depth of the wall in the case of the tougher wall mounts with aluminum tunnels.
The second method is to frame the wall yourself (or have your professional do it) generally using lumber to build a wood tunnel through the wall. In either case the tunnel is carefully caulked to guarantee water-tightness and any wood utilized is sealed. While framing yourself is most likely going to involve more work and expense, it does have the advantage of permitting you to utilize practically any pet door for your wall setup.