I use 1 1/2" foam board. I try to save my tops as much as possible. I'm on my third set of tops. It's a very nice house, finished basement and four car garage with finished storage space above garage complete with its own stairs. House is about 4 years old. We did multiple remodeling jobs on their previous home. Almost 400,000 dollars over the years, then they decided to Retire and down size. Super nice people. I like people who make big money and like to spend it.