Empty schools can look quiet during summer break, but their roofs, plumbing, and heating, ventilation, and air conditioning (HVAC) systems remain active. With fewer people present to notice a musty odor, a stained ceiling tile, or water under a mechanical unit, a small moisture problem can spread for days or weeks.
The U.S. Environmental Protection Agency (EPA) warns that summer breaks often end with significant mold problems in schools. Higher outdoor humidity, reduced cooling-system operation, and moisture from carpet cleaning or painting can combine to create favorable conditions for growth. The agency notes that only a couple of weeks under those conditions can lead to an expensive cleanup.
The risks are not limited to repairs. A recent account from the National Education Association shows the human and operational stakes. Educators at a Maryland elementary school reported recurring leaks, damaged materials, persistent humidity, and mold concerns that repeatedly returned. The problems often worsened while the building sat largely unoccupied during summer break, with staff returning to warped materials, damaged furniture, and mold in previously unaffected areas. During the school year, 22 students and staff members became ill after spending time in one classroom, prompting an evacuation and an air-quality investigation. This shows how persistent building concerns can take rooms out of service and erode staff confidence.
School facilities staff should use the summer window to find the water, correct the building condition, and verify that affected areas are ready for occupancy. The work should begin with moisture, not with a search for a particular type of mold.
Inspect the Building in Layers
A useful inspection should start with the building envelope and work inward. On the roof, where conditions allow safe access, facilities staff can look for drainage problems, damaged flashing or penetrations, and areas where water has previously collected. Around the building, the focus should shift to whether gutters, downspouts, grading, and irrigation are carrying water away from the structure. Windows and doors may also need closer review after periods of wind-driven rain.
Once inside, facilities staff should trace where water may have traveled rather than stopping at the first visible sign of damage. Ceiling stains, peeling paint, swollen baseboards, or loose flooring can all indicate current or past moisture intrusion, as can rust near diffusers. Odor matters, too. A persistent musty smell may justify closer attention in spaces that are especially prone to moisture, including basements, portable classrooms, storage areas, and rooms located beneath roofs or mechanical equipment.
Some moisture problems will not be visible on the surface. Noninvasive moisture meters, infrared cameras used under appropriate conditions, and humidity data can help narrow the search by showing where conditions differ from the surrounding area. These tools cannot confirm mold on their own, but they can help facilities staff determine when a closer inspection or limited opening of a wall, ceiling, or other finish is warranted.
The National Institute for Occupational Safety and Health (NIOSH) recommends thorough visual inspections and attention to musty odors over routine short-term air sampling. No health-based federal standard exists for indoor mold concentrations, and a negative air sample may miss an intermittent or concealed problem. NIOSH’s Dampness and Mold Assessment Tool for school buildings gives districts a repeatable way to document stains, visible damage, odors, and deterioration, then compare conditions after repairs. That record should carry into the mechanical review, since HVAC performance often explains why damp areas recur.
Test HVAC Operation Under Summer Conditions
Temperature alone is a poor measure of summer readiness. A classroom may feel cool even when relative humidity remains high enough to cause condensation on cooled surfaces or inside concealed cavities. EPA guidance calls for indoor relative humidity below 60%, ideally between 30% and 50%. Trend data by zone will reveal persistent conditions that a single handheld reading can miss.
Facilities staff should begin the HVAC review by comparing cooling and dehumidification schedules with actual summer conditions and occupancy. Condensate drainage, insulation, filtration, outdoor-air dampers, and control sequences then need to be checked as parts of the same moisture-management system. Standing water or wet insulation may indicate a maintenance fault, and an incorrect control sequence can continue to introduce humid air after occupants leave. Schools that scale back HVAC operation to save energy still need enough cooling or dehumidification to control moisture. Qualified HVAC personnel can determine the proper approach without compromising ventilation when the building is occupied.
Summer maintenance can introduce another source of humidity. Carpet cleaning, painting, and similar work should be timed around the building’s ability to remove that moisture. Monitoring humidity through the drying period gives facilities staff a firmer basis for reopening rooms than relying on a surface that merely feels dry.
Fix the Source, Then Clear the Space
When water damage is found, speed matters. NIOSH advises drying wetted materials within 48 hours or removing them. Remediation should address the condition that allowed moisture to enter rather than cover the evidence with paint or replacement finishes, since a cosmetic repair can leave the underlying problem untouched and allow damage to return.
The summer maintenance window offers something the school year rarely does: access to rooms without displacing classes. A district that inspects now, assigns responsibility for each finding, and verifies repairs before move-in can reduce health concerns and avoid rushed closures after students return. The most effective mold plan is a disciplined moisture-management program that continues through weekends, breaks, and every season the building remains in service.
Tim Eyre is VP of marketing at property restoration services provider RestoPros.