With plenty of legs, but no arms or hands, pets are hopelessly challenged when it comes to opening doors. While many Mensa dogs can open a sliding door, or even a hinged door, they never close them (it’s not on their agenda), and your home fills with insects in summer and cold draughts in winter. Installing a doggy door or cat flap is surprisingly easy. They cost between $50 and $300 each, depending on size and design. For a little more, you can even buy a door panel that clips between a sliding patio door and its jamb and incorporates a dog door or cat flap. Just make sure the flap is light enough so your pet can push against it.

Pet door in solid-timber door

GATHER YOUR SUPPLIES
Dog door suitable for your pet (we used Ultra-Flex door for a large dog); measuring tools; drill; jigsaw; screwdriver

Step 1 Measure the height of your dog at the shoulder and add another 60mm. This is the ideal height of the top of the flap opening. Mark this on the door, then use the door lock-out slide (security flap) as the template to mark in the cut-out shape. Make sure it’s level and centred in the door.

Step 2 Use a drill with a drill bit large enough to start your jigsaw and bore a hole in each corner.

Step 3 Cut out the opening with your saw, cutting as straight and as accurately as possible. Cut back into the corners, making sure they are square.

Step 4 Once the hole is cut, it’s time to involve your dog. Encourage him or her to walk through the opening in the door several times in both directions, so your pet gets used to it. Make it a game.

Step 5 Push the outer frame into the opening from the outside, then add the inner frame with the flap, and screw together. Except for the vacuuming of the sawdust, the job is done. Train your dog to see that the flap is safe to use and will not hurt it.

Pet door in security-insect screen door

GATHER YOUR SUPPLIES
Security screen door; measuring tools; masking tape; ear and eye protection; angle grinder; file; utility knife; double-sided tape; screwdriver; Lok-Tite

Step 1 If installing a security door alone, measure the height of your dog (see Project 1) and mark size of opening on screen door with masking tape. Take the size from the inner frame of the dog door. Make sure bolt holes will have clearance and that it’s level. If matching a dog door with the timber door, ensure each is aligned.

Step 2  Wearing eye and ear protection, use an angle grinder to cut through the security grille. File sharp edges smooth. While you could try a hacksaw or bolt cutters to cut the metal, these tools are more difficult to use to achieve a neat job. Do not touch the screen when cutting.

Step 3 Cut the fly wire with a sharp utility knife using the cut security mesh as a guide. Apply double-sided tape to the flat surface of the inner frame.

Step 4 Remove the other side of the tape and install from the inside, making sure it’s straight and holds the flyscreen. Add the outer frame and screw together. If required, add a little Lok-Tite or similar, to ‘glue’ the threads together.

NOTE: Choose a flap that corresponds with the dog door in the door behind, so your dog can push both simultaneously.

Pet door in a sliding patio door

Normal flap-type pet doors can’t be used in sliding doors as the flap may get caught and break. But there is a solution – a pet patio door. This is a self-contained panel that locks between the top and bottom tracks of sliding patio doors and incorporates the dog door. These are available from Pig In Mud.

GATHER YOUR SUPPLIES
Pet Patio Door to suit your pet size – no tools are required.

Step 1 Set the bottom of the door panel in the bottom track of the sliding door.

Step 2 The top of the panel is spring-loaded. Pull it down to fit into the track then, once secure, use the 2 knobs to lock the top in place.