Dear Sharon,

I suggest buying some peppermint oil. Put some drops in some water, soak
some cotton wool balls in it and put them in the roof in some saucers or
bowls. Rats hate peppermint and will not return because of the smell. Keep
in mind, you will need to go into the roof every so often and replace the
cotton balls if you want to keep them away for good.

Put some peppermint plants in your garden as well as an added deterrent.

Hope this helps, let us know how you go!

Glenda