5 pressure treated 2x4x8. Framed in the doorway and installed the screen door. Still to do. I have some black 1/2" fencer wire coming. Going to turn it into a small catio. Total cost, about $240 for the wood, screen door and fencer wire. Already had all the screws etc. I needed.
We have a cat that loves to run out the door when you open it. I need to build a screened in porch to keep him from getting out.
Yours looks great.