Be sure your contractor has the required personal liability, property damage and worker's compensation insurance for his/her workers and subcontractors. Check with your insurance company to find out if you are covered for any injury or damage that might occur.
To deter mold, keep indoor humidity low. If possible, keep indoor humidity below 60 percent (ideally between 30 and 50 percent) relative humidity. Relative humidity can be measured with a moisture or humidity meter, a small, inexpensive ($10-$50) instrument available at many hardware stores.