Here are some Common Pet Door Installation Problems and Suggested Solutions

	You've got a hollow-core or steel door Best bet is to purchase a self-framing pet door. Then you may skip the framing part below. If you've already got a pet door that isn't self-framing, you'll need to frame the hole as shown. To do that you're going to need a table saw to rip the pieces to the correct thickness. Glue in place, clamp and let dry. Then mount the pet door. The only difference in a steel door is that you use a different saw for cutting the hole. Jig saw with a metal cutting blade works best.
	Your door has an irregular surface Every pet door wants to be installed on a flat surface so you'll need to make it flat. It's probably a good idea to choose a sturdy metal-framed pet door for this application. The plastic-framed ones are easier to distort if the surface isn't perfectly flat and any distortion may cause the flap to bind and not swing freely. The best, neatest way to handle this situation is shown: cut furring strips just thick enough to bring the thinner areas up to the same thickness as the thicker areas. Cheater method: Get a self-framing pet door and make each of the four corners the same thickness. Then caulk in the spaces between the corners.
	You've got a screen door You could have chosen a simple pet door from the screen mount page and installed it directly through the screen. However, this method--which uses a door mount type pet door--is much sturdier. Of course, you can also cut down into the base of the door to reduce the step-over for a shorter pet. Don't cut so far that you weaken the door frame though! Note that this same approach may be used for a screened-in porch: add framing members to support a door mount pet door.
	You want your pet door in a wall Easiest is to purchase a 'self-framing' manual wall mount or electronic wall mount pet door. But if the particular pet door you want is designed for installation in a door you probably still can install it in your wall if you have the skills to frame the wall yourself. We th ink it best to hire this job out to a contractor. It's a big problem if you cut into electrical or fail to seal the wall properly against weather.