Small Projects #45: Cat proof screen porch

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Blog entry by Madmark2 posted 05-04-2021 02:41 AM 751 reads 0 times favorited 3 comments Add to Favorites Watch
« Part 44: Buffer storage box (in process -- no pics yet but stay tuned) Part 45 of Small Projects series Part 46: Prism Stand »

The screen porch screens have seen better days. They’re at least 15 years old and showing their age.

Where we live in fla development is displacing natural habitat of all sorts of critters — including what appears to be Florida panthers. Big tawny cats are regularly spotted in this area and last fall one of our kitties got out and met an untimely end.

Since then the porch has been off limits for both kitties and puppies. Seeing the cats longing for the outside got me thinking of ways to inexpensively allow porch access just for the cats while not permitting actual outdoor access.

I put a cat door in one of the kitchen windows that opens onto the porch.

Cat flap from kitchen window.

The cat door used allowed variable mounting thickness from effectively zero to 1-3/8” thick. The bottom of the sliding portion of the window has a 1/2” gap on the bottom that fit perfectly over 1/2” ply.

The ply was cut 3/4” wider than the opening to allow the sides to be covered by the aluminum window frame.

The plywood had to have the upper corners notched 1”x1” to leave room for the spring counterweight. The notches were cut on the band saw.

I used the scrollsaw to cut the cat flap opening. We’d purchased a magnetic flap that I just traced the outline of to dimension the opening. The upper corners meet at 90° while the lower corners are rounded with about a 3/4” or 1” radius.

Once the basic opening was cut, a little touchup with 120 grit 5” ROS perfected the fit. A 1” sanding cylinder in the hand drill helped contour the round corners.

The door inside and out was secured to the 1/2” ply by 4, #6 1/2” wood screws, one in each corner.

The 1/2” ply containing the door was installed in the opening and the sliding portion of the window was drilled and screwed to prevent an intruder opening the window fully for access. The ply fit into the slot on the bottom of the window snugly with little room for movement.

The outside of the ply was shimmed to fill in the track and prevent the door panel being moved to either side. Again for physical security.

In addition we lined the inside of the porch screens with 72” tall chicken wire. This will cover any existing push-outs or tears in the screens.

I bought a box of 1/2” self drilling/tapping screws with wide flanges. This allowed “point & shoot” metal screw attachment of the wire mesh to the existing aluminum screen frame.

Every foot or so there is a expansion limiting wire that prevents over extending the mesh. As luck would have it one of these wires fell reasonably close to the center of the horizontal struts. Using this as a reference we were able to quickly and neatly locate the mesh and screw it in place.

Lets see the cats get thru THAT!

A friends dog had crashed out the midsection of the screen door. We’d previously installed expanded metal mesh to prevent both cats and larger dogs from busting out (or anything else from coming in!)

A couple minutes with yellow (straight) aviation snips were all that was required to trim to fit.

The bottom of the wire was intentionally left a couple inches long to allow face screwing to the base plate. However the stiffness of the wire fileted at the floor makes it unlikely that the kitties can “dig” under it. But the LFB’s (Little Furry [email protected]@rds) are pretty clever — we’ll see.

We showed the dominant Tom the flap and after a couple of shoves he figured out both how to get in & out. He’ll teach the others by example.

  • 72” x 50’ chicken wire — $55
  • magnetic cat flap — $25
  • self tapping washer head 1/2” screws — $8 bx/100
  • 1/2” ply — shop scrap
  • 2’x2’ expanded metal mesh — 2 @ $22 ea

Matl. Total: $132

  • 2 hrs shop for door install
  • 1 hr x 2 ppl for wire mesh install

Labor Total: 4 hrs @ $20 / hr = $80

Project Cost: $212

-- The hump with the stump and the pump!

3 comments so far

View jeffswildwood's profile


4890 posts in 3061 days

#1 posted 05-04-2021 11:59 AM

Very nice idea to let the kitties get some fresh air. It won’t take long for them to get the hang of that cat door. Good idea to have the bottom attached tightly. I have to ask though, is there a way to keep them from going out the top? Does it go to the roof? We have a fence around our garden to keep the deer out and our tom cat went in and climbed the fence to get out, going over the top of a seven foot fence.

-- We all make mistakes, the trick is to fix it in a way that says "I meant to do that".

View Madmark2's profile


2660 posts in 1672 days

#2 posted 05-04-2021 02:01 PM

The chicken wire is 6’ and the screens are 7’+ so there is a gap up top. But the top screens are in better shape than the bottoms. We’ve got wire to spare, if they get over the top I’ll just have to extend the top.

So far (less than 24 hours) the dominant Tom is in and out like a shot and two of the other kitties have figured it out.

SWMBO is setting up a play area with beds and toys for them out there.

Happy kitties, happy wife, happy life.

-- The hump with the stump and the pump!

View robscastle's profile


7878 posts in 3288 days

#3 posted 05-10-2021 07:14 AM

some moggie lovers go all out! ... look at this construction I did for a friend

both units were interconnected so their cat could leave the house stay on the verandah or transit down a ramp to the ground all enclosed and feral safe.Dont seem tp have a completed picture showing it alll

-- Regards Rob

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