Cats on roof

[lindabible]

We have cats in our townhouses using the roof as a huge litter box. When the roof was redone they used pea gravel and the cats are using this as a huge litter box. Should the roof have a different type of gravel? How can we keep cats off of the roof?

[Hamiltonandy]

How do they get onto your roof?
Cats are very sensitive to smells and I find a very dilute solution of jeyes fluid or creosote will hide original smells and put them off. However will need renewing after a few weeks.
More permanent solution is to remove gravel and paint surface with protective layer to stop sun damage.