We have decided to carpet the basement. What is the best type of padding to use for the basement?. Also, is it a good idea to lay poly down b/4 installing carpet, or would this cause a problem with trapped dampness under the carpet? In an area where we will be installing floor tiles, there is residue from mastic from the previously installed rubber backed carpet. Is it okay to apply new adhesive over the old if I scrape off as much as I can? Thanks for any help that can be provided.