the problem you have is the flap needs to open in both directions by the cat pushing
any attempt to stop the wind getting in will stop your cat getting in
your only choice is a new flap away from direct winds in a protected walkway for example
or an expensive motorized one that will operate from a collar
1) Duct tape a weight (eg a piece of steel or lead) onto the plastic door/flap low down on the inner or outer face. This made the door heavier so it was less likely to blow open. It still was draughty round the edges but it was less likely to open fully! This was just about OK.
2) Build a wooden box on the outside wall covering the cat flap but with a side away from wind open. Make it big enough for your cat to walk through! Mine was about 12 inches square & I covered it in shed roofing felt to waterproof it. This WAS effective, keeping rain & wind out.
I know of no way at all to completely draught proof a catflap, tho.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local