I live in NJ - my home is on a crawl space which was flooded during a bad storm several years ago - right up to the floor boards. Since that happened, my floors have been very cold during the winter. I am hiring someone to re-insulate - is it necessary to remove the old insulation first? I am sure that it got wet during that storm. The contractor I am hiring proposes installing a 'blanket' right over it. Also - What R value should it be?