I was contacted in December by Jan with their catio building story:
The first incarnation was small and tall, but my daughter found that the kitties wouldn’t use the tall side unless bribed. So then we took that end apart and added some more panels to extend it along the wall and onto the lawn a little. The kitties now have an actual cat door installed in the window opening that they have no problem with. So, it’s only 2 levels high, and they use it in the winter, too. The only issue is snow blowing in sideways! This is in British Columbia, Canada. Oh, the levelling boards are hidden by the greenery later in the summer! The shelves are 1x6s attached with zip ties. The roofs are corrugated plastic secured with zip ties. They are to keep rain out of the window and off the cars and for shade. They are on an angle so the rain runs away from the house. The catio is secured to the window frame with fence staples and zip ties to the railing, and with tent pegs where it has an open bottom on the lawn.
You do want to wear gloves to do up all the zip ties and have pliers to tighten them well!
Feel free to use any info to help other catio builders. Pearl and Marsten love their catio!
Jan, I love how they have that grassy area and also the planter boxes at the bottom. This looks fantastic for them and I am glad they are enjoying it!