I've often thought about doing exactly that to our patio, for the same reasons. In that situation, I'd probably insulate between the 2x4s, put up a vapour barrier, cover it with 1/4" exterior grade plywood, and paint it. Use an exterior grade paint, it's going to be subjected to the outdoor temperature cycle and interior paint just can't take that. I'd insulate it because at some point you, or some other owner of the home, might want to turn that into interior space, and it'll add only a tiny fraction to the cost to do it now. It'll also make it a little warmer in there than the real outside temperature, which your cats might appreciate, unless the windows are really just screens and the space isn't really sealed against the outside. But if you have even single pane windows in there, it's worth insulating. It's like adding more insulation to the house's exterior wall, it'll reduce your heating costs and make that space usable for you, not just the cats, for a greater part of the year.
Yes, the windows are only screen. OK, 1/4" plywood, that's
good, just wanted something that would withstand the cold.
We haven't even discussed sheeting on the inside of the
walls, we were just going to leave it as is, but I have been thinking about it, for looks, so I will make that suggestion to my husband. Good advice about the paint, I'll
remember that.
Since our old cat died, I have decided to keep our new ones
from roaming around, my one cat is a registered maine coon
kitten, and the agreement on the contract, requires me to
keep her in, so I have to do that. I have had cats since
I was a little girl, never ever thought about keeping them
in, seems mean to me, but I have taught the siamese kitten
to go on the leash, and he allready is like a dog now, seems
to like it, and while I work in the garden I tether him to
a pole, and he can roam in a 16ft radius, and the lead will
pull longer or shorter with him, so he doesn't get tangled,
(only in the rhodos).
Thanks.