Office Building Mold and Air Quality Testing

Most office calls start the same way. Someone on the third floor says the air is making them sick. Two more people agree. The complaint goes to HR, HR sends it to facilities, facilities sends it to the landlord, and now there is a paper trail and no data. What ends that is a third-party assessment that either finds a source or documents its absence, in writing, by location, with an outdoor baseline.

We test only. No remediation, no bids, no referral fees from the contractors who fix what we find. In a landlord and tenant situation that independence is the difference between a report both parties accept and a report one side hired.

Small offices under 5,000 square feet run $650 to $950 depending on sample count. Full floors and multi-tenant buildings are quoted, typically $0.10 to $0.20 per square foot plus per-sample. Net 30 for established accounts.

Why office complaints cluster the way they do

In a house, a mold source affects the space near it. In a commercial office with a ducted system, it does not. This is the single most important thing to understand before designing a sample plan, and it is why so many office investigations look for the problem in the wrong place.

Air handlers distribute particulate along their branches. A wet condensate pan, a saturated section of internal duct liner, a section of lined plenum that got wet during a roof leak, or a return path drawing across a wet chase will produce complaints in every space that unit serves. Those spaces may be on different floors, may be nowhere near the water, and may skip the office directly under the leak because it happens to be on a different zone.

So the first question is not where are the complaints. It is what serves the complaining spaces. Get a mechanical zone map, or at minimum walk the roof and the mechanical rooms and trace it. Complaint locations that map cleanly onto one air handler point at the system. Complaint locations scattered across zones point at something else, often the building envelope or something entirely unrelated to mold.

The other office-specific factors worth naming:

Perimeter versus interior. In a Spokane winter, exterior wall and window assemblies run cold. Interior offices do not. Condensation complaints concentrate on the perimeter, especially on north and east elevations, and especially in buildings with older curtain wall, single-pane or first-generation replacement glazing, and uninsulated spandrel panels. Interior zone complaints with no perimeter pattern are usually mechanical.

Above the ceiling. In most offices the return path is the plenum above the ceiling tile. It is also where the roof leaks land, where the fire sprinkler lines run, and where the insulation gets wet. A stained ceiling tile is a symptom of something sitting on top of it that nobody has looked at.

Not everything is mold. A meaningful share of office air quality complaints resolve to inadequate outside air, low relative humidity in winter, off-gassing from new carpet or furniture, printer and toner particulate, or a building pressurization problem drawing garage or loading dock air into occupied space. ASHRAE 62.1 sets the ventilation design guidance most of these buildings were built to, and a system that has drifted from it produces real symptoms with no fungal component. We would rather tell you that than sell you a mold result.

Whole-floor versus targeted sampling

Buyers frequently ask for one or the other without a clear reason. Here is the actual decision.

Targeted sampling is the right call when complaints are confined to identifiable spaces, when there is a known water event with a defined location, or when you are validating a specific area before or after work. It is faster, cheaper, and produces a sharper answer. Typical design is the complaint space, an adjacent space, a comparable non-complaint space as an internal reference, and an outdoor control.

Whole-floor or systematic sampling is the right call when complaints are diffuse and unmapped, when a mechanical system is suspected and you need to see whether the pattern follows the ductwork, when a lease or a dispute requires demonstrating condition across a defined premises, or when you are documenting a floor before a tenant takes occupancy.

Adding samples is not the same as adding information. Nine samples pulled without a hypothesis produce nine numbers. Five samples pulled to test a specific question produce an answer. We will tell you which you are buying.

Landlord and tenant, who is responsible for what

We do not give legal advice and this is not a substitute for reading your lease. But the pattern repeats often enough to describe.

Most commercial leases in this market allocate the building structure, roof, exterior walls and base building mechanical systems to the landlord, and the interior of the demised premises to the tenant. That means a roof leak or an AHU condensate failure is typically a landlord matter, and a tenant's own plumbing under a break room sink or a supplemental cooling unit they installed is typically theirs. Repair obligations, rent abatement, and any express indoor air quality or hazardous materials clause vary widely, and full service gross leases handle it differently than triple net.

What matters operationally is this. Both sides usually want the same first thing: an objective determination of what is wet, where, and why. Retaining a tester who also sells remediation puts the other side in a position to dismiss the report. Retaining an independent tester, or better, agreeing jointly on one, produces a document both parties can work from.

We will take direction from whoever engages us, we will send the report to whoever the engaging party designates, and we will not offer either party an opinion about fault or lease interpretation. We report condition, extent, and moisture state.

What the assessment includes

• Air sampling with a calibrated pump drawing a measured volume through an Air-O-Cell or Allergenco-D spore trap cassette, submitted to an accredited laboratory for direct microscopic examination
• An outdoor control sample, every job. Outdoor air always contains mold spores. Elevated means elevated relative to outside, same building, same day. An indoor count with no baseline cannot support a conclusion, and in a landlord and tenant dispute that omission will be the first thing attacked
• Surface sampling by swab or tape lift on visible growth, including ceiling tile, gypsum, and the interior of mechanical equipment
• Moisture mapping with pin and pinless meters
• Thermal imaging for temperature differentials behind intact finishes, at perimeter assemblies and above hard-lid ceilings
• Borescope inspection of wall cavities, chases and above-ceiling plenums
• Psychrometrics by zone: temperature, relative humidity, dew point, indoors and outdoors
• Mechanical walkthrough where implicated: AHU interior, coil and drain pan, filter condition and MERV rating, visible duct liner, outside air damper position, return path
• Written report with photographs keyed to a floor plan, raw laboratory data, indoor to outdoor comparison, chain of custody, and stated method and limitations

Testing without shutting the floor down

We schedule after hours, overnight and on weekends at no premium, and we can work zone by zone so only one area is affected at a time.

The visible footprint of air sampling in an occupied office is one person setting a pump on a tripod for five to ten minutes per location. It does not require clearing a space. What benefits from after-hours access is ceiling work, borescope inspection, and anything in a mechanical room.

One judgment call worth making deliberately: occupied or unoccupied conditions. Foot traffic and door cycling resuspend settled particulate, so a sample pulled at 2 p.m. and one pulled at 6 a.m. in the same room are different measurements. If the question is what occupants are breathing, sample occupied. If the question is whether a reservoir exists, sample quiet. We record which condition applied.

Pricing

Laboratory results normally return in 1 to 3 business days, with the written report within one day of that.

The independence, once

Washington's Department of Health states plainly that there are no certification requirements for mold work in the state and that anyone can call themselves a mold specialist without training or credentials. Idaho licenses neither mold work nor home inspection. In that environment nearly every firm marketing mold testing here also sells the cleanup, which means finding a problem generates revenue and finding nothing does not.

New York prohibited that arrangement outright under Labor Law Article 32, which bars one company from both assessing and remediating the same property. Washington and Idaho have no such rule. Ours is a choice, and it is the reason a report with our name on it is usable by both sides of a lease dispute.

We also keep health language accurate. CDC has never established a causal link between Stachybotrys and serious illness, and says no test proves an association between a specific mold and particular health symptoms. Documented effects are allergic reaction, asthma triggering and upper respiratory irritation in sensitive people, plus serious infection risk in the severely immunocompromised. We do not diagnose anyone and we do not attribute symptoms.

Questions

Employees are reporting symptoms. Can testing tell us the building caused them? No, and be cautious of anyone who says it can. Testing establishes whether elevated fungal concentrations or growth conditions are present. Attributing individual symptoms to a building is a medical question we do not answer.

How many samples do we need? Enough to test a specific hypothesis, usually three to nine for a suite or floor including the outdoor control. We will propose a count with reasoning before you commit.

Can you inspect the HVAC system? We inspect and document AHU interiors, coil and pan condition, filters and accessible duct liner, and we sample inside equipment where warranted. We do not clean systems and we do not bid duct cleaning.

Our tenant hired their own tester. Can you review that report? Yes. Send it over. We will tell you whether the method supports the conclusion, starting with whether an outdoor control was collected.

Get a quote for your building

Send the address, rentable square footage, floor or suite in question, what the complaints are, and any mechanical drawings you have. We will return a written sampling plan and a fixed price.