Removing Large Amounts. For large areas of black mold, you need to hire a professional to safely remove the mold. This can cost you thousands of dollars, depending on how extensive the mold area is. Just to remove mold from a crawl space or attic can cost you $500 to $4,000 in 2010, according to Blackmoldexpert.com. Bigger areas like a basement will run around $7,000. If the mold has caused structural damage or ruined furniture, then you will also have to factor in the repair and replacement costs.