I bought my Block Butler about a year ago. I absolutely love it. We put up the insulated foam board and then placed the Block Butler on it. This product comes in 2 sizes: 36" X 36" and 72" X 72". It is sticky on both sides so installation is not an issue. If there comes a time when it is not tacky enough for your blocks, just spritz it with a little water. Hope this answers your questions. *s*