Re: mold on drywall in basement
Whether or not it can grow as a result of that gap depends on moisture migration from that spot upward and to what extend the moisture is available to the mold there. It may be a slow moisture intrusion through the cinderblock walls (an issue of humidity rather than liquid water - why you don't see it). In either case there is the possibility that there may be hidden mold. Either way the mold that you see may be only part of the overall pollution problem. What I'm referring to here is the mold's effect on the indoor air quality. I'm going to share with you some resource materials where you can (for free) contact professionals through forums and emails (no obligation to use their business), links to industry experts, information on mold, and links to remediation professionals. I hope they help direct you toward the path of remediation and closure. God bless!
Jason Yost, CIEC, CMRS, WRT
Council-certified Indoor Environmental Consultant
Council-certified Microbial Remediation Supervisor
Water-damage Restoration Technician