My cat will start pooing in doors as soon as the weather turns wintery, or wet. It's very annoying but it coincides with winter. Last year she kept weeing in the same place on the carpet, So I fed her there and that seemed to stop it.
This year I have had to remove our door mat and now have a plastic runner down which is easy to clean. I have also given her an extra litter tray which does help but I have to clean it out as soon as there is anything in it.
I would give your cat a litter tray and feed her as near as possible to where she is soiling.
He may well have used a tray in his kittenhood. I'd get one and see if he uses it instinctively. If not, try him on it a few minutes after he's eaten. (Put him on it and position him with some loving words.)
Could be the change in the weather, he might not want to go out if it is cold, wet and windy. Or could be a health problem. As a rule any change of toileting behaviour should mean a trip to the vet. In the mean time do get a tray set up and encourage him to use it, for the ske of the entire household!
Our Cat doesn't have a litter tray. We inherited him from mil and he has always gone outdoors to do his business. The last couple of days he has started pooing under the cooker (there is a bit of plinth missing).
he is a teenager (we think) mil took him in years ago from a stray.
why would he suddenly start pooing onside, does he need a trip to the vet? Should we buy a litter tray?