To trim our door, we bought a jamb kit and ripped two pieces of it to 13/8 in. wide for our 15/8-in.-wide door. We installed these at the top and side of the door opening.

Home & Garden Interior wall framing not the easy job it might seem to be Updated: Dec. 30, 2011, 3:56 p.m. | Published: Dec. 30, 2011, 2:56 p.m. By Tim Carter/Ask the Builder ...

Some people buy pet-door kits made for installing into a door and then build a box to slide into the hole in the wall. That is OK if you use a material that will stand up to the weather and the pet.