Sick building syndrome: symptoms tied to a building with no single diagnosis. Learn the causes, from VOCs to humidity, and how Florida buildings get tested.
Half the staff in the back office have headaches by two in the afternoon. Someone in accounting keeps a box of tissues on her desk from September through May. Everyone feels better on Saturday. When a pattern like this appears in an Orlando office, a Villages clubhouse, a classroom or even a single family home, the label people reach for is sick building syndrome. The label is useful as long as you understand what it does and does not mean.
What sick building syndrome is
Sick building syndrome (SBS) is a term for a set of nonspecific symptoms that occupants link to time spent in a particular building, without a specific illness or cause identified. The symptoms typically ease within hours of leaving and return on re-entry. Common complaints include:
- Headache
- Eye, nose and throat irritation
- Dry cough
- Dry or itchy skin
- Dizziness and nausea
- Difficulty concentrating
- Fatigue
- Heightened sensitivity to odors
The word "syndrome" signals that this is a pattern of complaints, not a diagnosis. It contrasts with building-related illness, where a physician identifies a specific condition, such as an allergy to a particular mold or an infection, and connects it to a confirmed exposure in the building. Many investigations begin as SBS and end with one or more specific causes found.
Why the causes are usually plural
Buildings rarely have one problem. Investigations tend to find a combination of factors that together push a sensitive portion of the occupants over a symptom threshold. The most frequent contributors fall into a handful of categories.
Inadequate ventilation
Modern buildings are sealed for energy efficiency. If the mechanical system does not bring in enough outdoor air for the number of occupants, carbon dioxide and body-generated pollutants build up through the day. Carbon dioxide itself is a useful marker: rising afternoon levels indicate stale air that is also carrying everything else the occupants and furnishings release.
Chemical contaminants from indoor sources
Volatile organic compounds from carpet, furniture, paint, copiers, cleaning products and adhesives accumulate when ventilation is low. Formaldehyde from composite wood is common in new or renovated spaces. These chemistry problems are often invisible and odorless at the concentrations involved, which is why occupants may feel ill without noticing a smell. Our overview of volatile organic compounds in your home applies equally to offices.
Chemical contaminants from outdoors
Loading docks, parking garages, idling vehicles near intakes and exhaust from neighboring businesses can be drawn into the building. Pesticide applications and roofing work are frequent short-term culprits.
Biological contaminants
Mold in air handlers, ductwork, ceiling tiles below leaks and wall cavities releases spores, fragments and microbial VOCs. Bacteria in drain pans and humidifiers, dust mite allergens in carpet and pollen tracked in from outside add to the load. In Florida, the air handler and the humidity it fails to control are the usual starting point for this category.
Physical conditions
Temperature, humidity, lighting, noise and ergonomics all influence how occupants feel. High humidity makes air feel heavy and supports biological growth; very low humidity, which is rare here, dries eyes and airways. Poor lighting and glare produce headaches that are easily mistaken for air quality effects.
The Florida pattern
Central Florida buildings share a signature. Air conditioning runs nearly year-round, so the mechanical system dominates indoor conditions. When that system is oversized, poorly maintained, or operated to save energy with minimal outdoor air, three things happen at once: humidity drifts upward, carbon dioxide and VOCs accumulate, and condensation on cold components feeds microbial growth that is then distributed throughout the space. A single HVAC deficiency can produce chemical, biological and comfort problems simultaneously, which is why SBS complaints here so often trace back to the air handler room.
Buildings with intermittent occupancy, such as houses of worship, seasonal clubhouses and schools over summer break, add the problem of sitting closed and warm for weeks, then being filled with people the day they reopen.
How a systematic investigation works
Guessing is expensive. Replacing carpet because someone suspects it, or cleaning ducts because that is what the last contractor suggested, often changes nothing. A structured assessment narrows the field.
| Phase | Activities | Output |
|---|---|---|
| Intake | Interview occupants, map complaints by location and time of day, review building history | Complaint pattern and hypotheses |
| Walkthrough | Inspect HVAC, look for water damage, odors, pollutant sources, blocked diffusers | Prioritized list of suspect areas |
| Measurement | Log temperature, humidity, carbon dioxide and particulates in complaint and control areas; screen for VOCs and carbon monoxide | Objective comparison across zones |
| Sampling | Collect air and surface samples for mold, and VOC or formaldehyde samples where indicated, under chain of custody to an independent accredited laboratory | Identification of specific contaminants |
| Analysis | Compare complaint zones to non-complaint zones and outdoors; correlate with HVAC operation | Likely contributing factors ranked |
| Report | Document findings, mechanisms and recommended corrections | Action plan for management |
UES performs this kind of investigation through our indoor air quality and allergen testing and building forensics and specialized diagnostics services. Where mold is found, a written protocol is delivered in the UES Client Portal. Because UES does no remediation, HVAC repair or product sales, the report is not shaped by what would be profitable to fix.
What a physician contributes
Occupants with persistent symptoms should see their own doctors. A physician can rule out unrelated conditions, identify allergies that make a person especially sensitive to a specific contaminant, and recognize when a building-related illness rather than nonspecific SBS is present. When several occupants are affected, an occupational medicine specialist can be valuable. Assessment data on specific molds, VOCs and conditions gives physicians concrete exposures to evaluate.
Steps building managers and homeowners can take
- Keep a complaint log that records who, where, when and what symptoms. Patterns emerge quickly.
- Verify the HVAC system is delivering outdoor air as designed and that filters are correct and sealed.
- Hold indoor relative humidity below 60 percent; aim for 30 to 50 percent.
- Schedule cleaning, pest control and painting for unoccupied periods and ventilate afterward.
- Address any water intrusion within 24 to 48 hours, since mold can begin growing on wet materials in that window.
- Keep vehicle idling and dumpsters away from outdoor air intakes.
- Commission an independent assessment before committing to expensive corrective work.
When to call UES
Call when multiple occupants report similar symptoms that improve away from the building, when complaints cluster in one zone or one shift, when a renovation or a water event preceded the complaints, or when management needs documentation for insurance, employees or residents. Book an assessment online or call (407) 438-4684, Monday through Friday, 9:00 AM to 5:30 PM.
Related reading
Frequently asked questions
What is the difference between sick building syndrome and building-related illness?
Sick building syndrome refers to a cluster of nonspecific symptoms such as headache, fatigue and irritation that occupants experience in a building and that ease when they leave, with no single identified cause. Building-related illness is a diagnosable condition, such as an infection or a specific allergy, with a confirmed link to a building contaminant. A physician makes that distinction.
How many people need to have symptoms before it counts as sick building syndrome?
There is no fixed number. The pattern matters more than the count: multiple occupants reporting similar symptoms that improve when they leave the building and return when they come back. Even a few consistent reports in a small office or a single household are worth investigating, because the underlying causes are measurable.
Can an indoor air quality assessment find the cause?
Often, yes. A systematic assessment measures humidity, temperature, carbon dioxide, VOCs, particulates and mold spore levels, inspects the HVAC system and compares conditions across areas where complaints are and are not reported. The results usually point to one or more contributing factors, which gives building management something concrete to correct.
Worried about what you just read?
An independent UES assessment tells you exactly what is going on, what caused it and what to do next. Book online or call.
