i've been told it is mold and the smell is real bad. Will it hurt the beams and should it be removed. Mold remeators charge 2500 to remove and seal beams. Can I get by for less. Should insulation be removed. Ply is down but mold is under it. I smell the crawl space smell in the house I am assuming thru boots. The ac vents smell and there is a constant fine dust problem in the house. There is wetness under poly in crawl. Will high powered ozone generators kill the mold or should I have the fungicide people sanitize the crawl. The heat pump and hvac system is 15 years old. should it be replaced. a few have recommended that we remove old insulation and the entire hvac system, sanitize crawl space and kill mold under poly, place new poly to code, install new insulation and then put in new hvac system. Also a french drain around backsides of house where water runoff comes toward foundation.