Cat deterrent

[Stylehelp]

Mum and dad have a flat roof extension with stones on it.

A local cat has started to use it as a litter tray. They have tried vinegar, cat deterrent pellets and spray.

The smell is pretty overpowering (it’s outside their bedroom window). To give an example they had it cleared last Thursday or Friday and the window cleaner came today and knocked on the door to say how bad the smell was outside and did they know. It has accrued that much over a few days.

Any tricks or products to use to prevent it from happening?

Or would the only way be to get rid of the stones and use a bitumen on the roof? (My dad seems to think that’s going to be very expensive.)

Remove the stomes. It's basically a massive cat litter tray.
Sprinkle pepper dust on the roof

I have exactly the same problem. I bought a huge fuck off water cannon type thing and blast the cat as soon as I see it. It doesn't appear quite so often now!

I'm trying to think of an environmentally and not cruel way of deterring. Firstly, when it's cleared, it also needs to be cleaned thoroughly too. So a bleach solution. How about putting down spiky branches/fir clippings, until the habit is broken. Sounds odd I know, but the only way we stopped cats was planting spiky plants. If they can't squat, they won't go!

Giant bag of dried chillies from ama..n..
Scatter a few handfuls..
Hardprune the roses... cut prunings into 6 inch lengths... scatter on roof
Then save for the bitumen..

We had the same problem - we used dried chiili flakes (huge bag from Amazon) and also some of those plastic cat spike strips on the parts of the roof that the cat was jumping up.
Next doors cat was the culprit but we have cats of our own and didn't feel the slightest bit bad about doing any of the above.

When they had it cleared, what was it cleared with? Did someone remove the stones to clean them or just pick up cat poo?

You'll need a really good enzyme cleaner to remove the smell of cat urine / poo, even the smell you can't smell but cats can - this identifies it as a litter tray to cats too.

How is the cat getting up there? Can you put spikes or netting along whatever wall or fence they're using to jump up from? Can you put physical barrier along the side of the roof the cat is getting onto?

I agree with taking away the gravel and using twiggery up on the roof itself as well. Cats don't like citrus peel either.

I don't think cleaning the area will help. It's the gravel up there making it a great litter tray. Cats like a clean litter tray!

Get a spray called Simple Solution & spray it all over the area. It neutralises the smell & discourages them from going there again.
Then do the things other folk are suggesting.

They don't like the smell of Jeyes Fluid