I dont think I'd be happy with a new molding over-top the old original molding.
I was looking at a wood reproduction screen door at home depot. I think it was about $200 Canadian. I forget if it had glass in it. probably? If you could get a wood one you could trim it or add a piece but with those aluminum ones changing size would take some doing.
I found an antique Victorian screen door and I have to get it painted and put the screen in but I fixed other issues , it had a really bad twist and some fancy bits missing. It wouldn't be too hard to create the simple type from scratch, Like the one that was always getting slammed on "the Waltons", I know it only had so many slams left in it
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I tried the screen I have It looked like it would just fit against my door casings, but my casings are a lot less ornate. At least if you make it fit a standard out of the box size then if you ever replace it you'll have an easier time. I cant' wait to get mine on there as my girlfriend doesn't like her cat outside and we need the airflow. I've probably had it 5 years so you are speedy by comparison
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