I placed the gasket that comes with the new light over the holes and drew a circle using the center hole in the gasket as a template. I took a 1/8 drill and drilled in the center of circle, be careful to go just as deep as necessary to get through roof. (I don\'t know whats underneath--do you? so be careful!! I then drilled a 3/8 hole using the 1/8\"pilot hole. The plumbers epoxy is something I have used for lots of filling jobs. It sets in about 20 minutes. Somehow some photos I took will not display so I will try and explain what you will have to do if you use my installation method. All the wires are foamed in place you have to carefully push foam away from both holes. I bent a small screwdriver to a 90 degree so I could remove foam from my new hole to old hole. Just be careful not to push hard on the wires and loose them in the ceiling.