Blocking up basement walls

[Kmarissa]

Hi all,

So, for a variety of reasons that aren't worth getting into, we're thinking of turning our attention to our basement, and making the space more generally usable and comfortable to be in--although it's already halfway there, since it has a concrete floor and heating/AC vents. It would never be up to code as finished living space, but it could be more comfortable and usable in a number of ways. One thing we'd like to do is move our litterbox into the area, and otherwise allow our cats to go down there.

But, it's a typical old house basement with lots of gaps and openings where the joists and framing rests on the foundation. I'm very worried that our cats, one of them in particular, will find ways to get herself up in the walls of the house, and won't be able to get out again. I've had a previously cat get stuck in the walls of an old house before, and although we safely recovered her, I don't want to take the risk again. Of the two cats I have now, one of them is very smart, VERY curious, has a great memory, is nimble, creative, and infuriatingly, impossibly persistent, so she will explore every cranny and find any accessible gap.

The question is, how do I stop up the gaps in a cat-proof manner? I've attached a few pictures to show the problem. For example, here's a support column, followed by a close-up of the space above the support column, showing a vertical gap between the walls (you can see the inside of the lath):

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And here's one of the foundation walls and joists above (the orientation of the insulation perplexes me), followed by a close-up of the dark gap between the insulation bats. What you can't really see clearly in the picture is that again, there's a vertical gap between the framing.

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IMG_8769.JPG (440.38 KiB) Viewed 3276 times

Cutting drywall or plywood to fit and block off each opening around the entire basement would probably work, but would be hugely time consuming. I've also thought about using heavy duty plastic netting, or something like chicken wire strategically stapled in place. We could probably also use cheap burlap or canvas, but I wonder how long a fabric solution would last. If we were actually fully finishing the basement then this would all be hidden behind a new basement ceiling, but that's not something we're planning to do. There are so many creative minds here that I thought it was worth seeing if anyone else had any ideas!

[phil]

I love cats but I don't' see it getting stuck in there. I guess anything is possible. they will crawl into every nick and cranny but they are pretty good at getting out too. How about stuffing it with insulation to block the airflow and kitty at least as a temporary measure?
my house had cardboard nailed to the studs, no insulation , holes in the shiplap. insulating and closing up the basement and doing some drywall helped so much to the basement and also the rest of the house. I just take on chunks, I didn't' do the whole basement but I did one wall , then some of the ceiling then a small room and it's ongoing but I cant' stand doing drywalling forever without a break from it so I just do sections. if it helps you can always scew on some drywall and not even mud or tape or fill and than it's easy to rip apart again if you want access and int he meantime it might be brighter. - or just use that cheap panelling everyone hates but it is fast and cheap.

[JRC]

If you fill the openings with mineral wool panels, you'd also be adding some fire stopping to your walls.

[Mick_VT]

I second the idea of using mineral wool, I would likely use Roxul bats sliced to size. Rodents hate the stuff, it is fireproof and doesn't hold moisture. It is very easy to cut to shape with a breadknife. If you like the idea of the netting route consider using wire rodent screen.

[nhguy]

I had gaps like that in all the old houses we've had. I was more worried about the mice, rats and skunks than the cats frankly. You might try 2" thick sheets of foil faced foam boards, screw them in place with a 2-1/2 inch drywall screw and a fender washer, so the screw doesn't pull through the foam board. Once installed you used canned foam around the edge to seal out the critters and the cold air.

[Kmarissa]

Thanks for the ideas, all! I had initially thought about stuffing insulation or something into the gaps, but went back and forth on the feasibility. I think you've talked me into it--I can just use a bit of duct tape to secure things if needed.

And Phil, believe me, if it was any other cat then I wouldn't be concerned. But this one cat of ours... well, we (very lovingly) refer to her as "the worst cat in the world." If it's physically possible for her to squeeze into a space and get herself stuck, then it's not just likely to happen, it's inevitable.

[vvzz]

Another good reason to block those holes is to stop air movement. That wall with lath showing is like chimneystack for your heat.

Speaking of cats and walls(or ceilings) I have a funny story that actually just happened last week. My second floor bathroom is on top of the kitchen and there used to be a leak from the bathtub overflow drain, so someone previously removed a portion of the kitchen ceiling(on top of existing drop ceiling) so the bottom of the bathtub was visible.

Additionally, there's a ledge next to the bathtub that I have recently removed, because it had tile directly over some early cement board or something, but whatever it is, it started to rot and smell. So there is a clear passage under the bathtub which inevitably attracted curious paws. You can see where this is going

So one night me and one of the cats were already in bed and my gf was watching TV downstairs. Then suddenly there's a loud banging, sound of pots and pans rolling, etc and I get a text saying that the 'kitchen ceiling has collapsed'. Of course I rush downstairs and it's just a couple of the dropped ceiling panels that fell down over the stove. I moved them not too long ago, so I just assume I didn't quite put them back into the tracks and maybe a wind gust made the house flex a little and dislodged them or something. I also notice that the cat that was sleeping with me upstairs is curiously observing the site(even though I remember closing the bedroom door and not letting him go down)

It took us about a day to put the facts together and realize that the kitty has found a new path to the first floor

[phil]

I agree with the Roxul as said just cut it with a bread knife. Cut it a bit too big so you compress it a bit and that holds it in place. I like it because it is a better sound blocker than most. The foil backed insulation board is good stuff too . I just did that in my living room with the spray foam. what I do is cut it to fit loosely then spray foam the edges near the studs. then I put a bit of plastic in front and nail some boards to keep the spray foam from pushing the insulation back out of the cavity until dry. then I remove the plastic and the board to the next stud bay. I noticed that I can get the stuff locally in 1 inch sheets now too.

If I put Roxul or fiberglass, I like to staple fishing line across the studs to hold it in place if it wants to fall out. then it's not in my way If I want to put vapor barrier or drywall over that.

My cat is a source of constant entertainment too. Shes so loving she'll jump in my lap and sleep and play with me. I can pick her up and hold her upside down and she just trusts me completely. around dawn and dusk she goes crazy and gets into hunting mode. She caught a big mouse in the house last week. I think she catches them in my firewood pile and she knows how to open the door if it isn't clicked right shut she will bring them in. . one mommy mouse and you have an infestation. She loves to play catch and release in the house with them. I don't think she's ever seen an empty food dish but they never loose their instincts.
One favorite toy is those foam earplugs. She can hook a claw in and toss them and she bats them all about. If she wants she will pick them up and carry them to where she wants to play. they are cheap so if she looses a few I just give her more. Year round she has those unbreakable cardboard like Christmas bobbles. they are light and roll pretty well and she loves those too. Last year I got a hold of a stump that someone made from balsa wood. I think they were trying to make a porch column or something with it. its about 15 inches wide and about 2 feet high. they glued them into a big block and turned it round like a stump. The balsa wood works great for her to scratch. It's actual wood but it's soft and doesn't mark the floors . she leaves a little mess to vacuum up but it works great. I often put some catnip on top and of course she likes that. If I keep the door open all her neighborhood friends come looking for the catnip and I start to feel like the neighborhood cat drug dealer lol..

Phil

[Lily left the valley]

One thing we'll be doing in the cellar is closing up the few spots that don't have anything in the wall to sill area as well. I have nothing new to add as to methods, I'm writing this in part to remind myself it's something we want to do sooner rather than later for similar reasons.

Mendel was the one who liked getting into places he shouldn't. Og liked making sure he stayed there. We know Kira finds every spot she can, but she's tiny and clever so we've never had a stuck situation, just a "oh no, the webs!" type.

One side by side we lived in had older door handles, and Mendel figured out how to open the door to the basement by jiggling it between his paws. Time and again, he would open the door, go downstairs to hang out with his buddy the furnance (he used to talk to it when it would kick on), and Og would close the door behind him. Since there was no landing inside the door, Mendel couldn't figure out a way to keep his balance and open it from the stair side. So then the crying would start, and one of us would have to let him out. I think we finally put a stopper in front of the door when winter winded down, and Mendel decided to explore the other side of the basement, and found that there was just enough room to squeeze into the unfinished area under the front porch--and right by the uncovered sump pump. We later figured out that's where most of the field mice were sneaking in when the fall chill would set in.

Out of our three...Og loved marbles. Mendel loved ping pong balls. Kira loves rubber superballs.

[Nicholas]

My cats keep finding 3 inch long baby possums. Happened again today. This is the 4th time in a month and I am having a hard time keeping life forms from tunneling under the lattice surrounding the crawlspace.