The free diy home improvement guide with answers to your questions on a wide range of do it yourself projects.

Fitting a Cat or Dog Flap

cat looking at camera waiting to go out

If you have a cat or dog then only you will know how annoying it can be to have to let them in and out of the house several times a day. Cats in particular are very early risers – f they come in at all – and are often mewing at the door at first light.

A cat or dog flap can make life much easier for the average pet owner and providing your pet is willing to use it, you will wonder why you didn't install one long ago.

Measure your pet

The first step towards installing a pet flap is to measure the size of your animal. Cats tend to be more agile than dogs and in most cases are smaller. It is very unwise to install a flap for a larger dog as the opening is likely to be large enough for a person to get in. Your insurance company will not be happy about that! You will also need to consider how high from the ground it will need to be. Generally it is about right to take that measurement from the ground to your pets body (ie the length of their front legs).

Mark the door

Transfer the above measurements to your door, positioning the centre of the flap to either one side or the middle depending on your preference.

Your cat or dog flap will come with a template which will allow you to mark the exact position on the door. The template will usually be a circle opening, large enough for your animal.

Cut out the opening

Use a jigsaw to cut the circle carefully. On panelled doors it is best to keep the circle within one of the panels as the integrity of your door will be compromised if you cut through one of the verticals. Smooth off the edges of the cut with sand paper. You should be able to cut through a PVC door in the same way as a timber one.

Fit the flap

The flap should now fit into the hole. You need to take care that you fit it the correct way. Some flaps have mechanisms which will allow the animal to only go one way, usually out. You may need to use some sealant around the edges in addition to the screw fixings. Your template should also show you where to drill the pilot holes for your screws. This will prevent it from moving around if the door expands or contracts at different times of the year.

Cat and dog flaps can also be installed in the walls next to the door, although this is a little more tricky. The two sections of the flap; the inner and out pieces may be further apart due to the depth of the wall. In addition the brick and block work will have to be drilled through. Specialist equipment may be needed to do this.

It is also a good idea to line the inside of the hole to prevent your animal from catching their fur or scratching themselves. The two sections of cat flap will have to be fitted individually to the outside and inside walls. It can take a while to knock through the wall when doing this option, but the result is better for anyone concerned about the safety of having a hole in their door.

Now the interesting part starts – trying to teach your cat or dog how to use it!