I am building an 8 X 20 porch on concrete piers. I would like to have the option of insulating the porch and heating it in winter ( I am located in the Northeast USA). I have not put in the piers yet, but am wondering if it is workable to do this, by using rigid foam between the floor joists, or if I would be better off pouring a foundation for the porch or using concrete block. I would really like to use piers because of the ease of installing them ( I can do it in a day with a post hole digger, instead of having to excavate below the frost line). Thanks,
-- Jeff