any water is to much water. water is one of the elements that is required to grow mold. If I were you I would get the insurance company information from the contractor and attempt to have his insurance company pay for the damages. More then likely the contractor insurance company will fight you for it.
Your second option is to call your agent file a claim and have your insurance company subrogate against the contractors insurance company. You will have to initially have to pay your deductible but if the subrogation is successful your deductible or a portion of it will be refunded back to you. Keep in mind that the subrogation can be a lengthy process and will test your patience.
You have the documentation showing damage in the attic, walls, drywall. You will be surprised at the dollar amount of the restoration repairs. The longer you wait the more chances you have of more damages and you have a duty according to your insurance policy to mitigate your loss from further damage.