How to safely walk on immitation slate roof.

Hi everyone

I found a faux slate rubbery roof impossible to walk on wet but surprisingly when I returned and tried to walk on it dry as it was still to slippery even on a mild pitch. It did get colder between visits. I have good quality grippy shoes.

Any advice on how to safely access the roof would certainly be appreciated. Will the roof be less slippery when the temperature is much hotter?. Will foam or sponge pieces where we walk help us?

Thanks Terry