How do I resize a pet door


I just bought a patio door secondhand. It was the perfect price but the pet door is too big. My concern is someone being able to crawl through it. How can I go about filling it in to put in a smaller door?

q how do i resize a pet door
  12 answers
  • Johnavallance82 Johnavallance82 on Sep 14, 2021

    Hi, You will need to place and secure a panel on the front and one on the back to cover the whole area and then trim around it.

  • If the new one is just a little smaller you could add a piece of wood or wide molding to modify the size. If it's a big difference in size, you may need a new door. Here's a link on securing a dog door:

  • J Brown J Brown on Sep 14, 2021

    Once you resize the opening the existing flap will no longer be able to swing in and out. You will probably need to purchase a new smaller flap.

    Might be better to look for another smaller door and resell the one that is too large.

  • Redcatcec Redcatcec on Sep 14, 2021

    A piece of wood on top of the inside of the doggie door would reduce the height of it, then attach a new flap for the smaller opening.

  • GrandmasHouseDIY GrandmasHouseDIY on Sep 14, 2021

    I agree a solid piece of wood across the top on both sides of the door to the height of the doggie door you would prefer would be about the only thing I can think of.

  • William William on Sep 14, 2021

    You would need to cover the existing opening with 3/8" or 1/2" plywood panels inside and out. Anything thinner will be too flimsy. Panels should be about 2" larger than the opening. You want a 1" overlap all around. Use glue and small nails to fasten them in place.

  • Kathy Gunter Law Kathy Gunter Law on Sep 14, 2021

    Can you put an insert at the top? I would go with white. Add a panel or two, similar to shiplap look.

  • Carol Carol on Sep 14, 2021

    I was thinking about it last night, could I put a trim over the edge to bring it in and use some kind of expanding foam to insulate? Then instal the new door in that?

  • Betsy Betsy on Sep 14, 2021

    Hi Carol: What I would do is to put a board across the bottom of the door, on both sides and cut the flap to fit. It will stick out a bit from the door, but you can cover that with molding. You can do that on the long sides, too, if you are concerned with the width.

    Good luck

    • Carol Carol on Sep 15, 2021

      Great. I just wanna trim it up like four or 5 inches off the length on the bottom. I was thinking about just getting a smaller door and filling in the void but this may work just as well.

  • Betsy Betsy on Sep 15, 2021

    I was just thinking about this last night. If you put the board across the top, you won't have to cut the flap to fit, and your puppy won't have to step up so high. Send him/her through the door a couple of times to see where it's back comes. You don't want the back to hit the top because not only is it painful, but it can scratch the hair off. I'd glue a piece of pool noodle to the bottom of the board to avert this, E-6000 works good. Hot glue may melt the noodle a bit. Take this measurement into consideration when adding the wood. I think this would be the easiest solution, and I'd still glue some decorative 1/4 or 1/2 inch round to the edges to hide the gaps.

  • Dee Dee on Sep 15, 2021

    Build in a piece of wood on both sides. Make it look intentional and decorative. Put some decorative molding around the square. Caulk and paint all the same color.

  • Annie Annie on Sep 16, 2021

    You would have to add a piece of wood securely, then put the new door into place.