How we test for mold
Measuring relative humidity (%RH) and temperature (deg F.) with a hygrothermometer:
To prevent and control mold growth, it is best to keep the temperature below 78 deg. F, and between 35-55% R.H.
Quality mold assessments always include analysis of temperature and humidity. Conditions outside those recommended limits will, in general, be a contributing concern for the presence of mold.
The hygro thermometer is a combination of a thermometer and a hygrometer. A thermometer is an instrument that measures temperature while a hygrometer is an instrument that can measure relative humidity. The hygrometer measures the moisture content in the air. Both these instruments are combined to make the hygro thermometer. Amazing isn’t it?
This instrument is very useful in determining the ambient air condition in any room of a home or office. It is a reliable indicator of suitable room conditions or developing problems within a room. When the temperature is too high, the humidity may drop and when the temperature low, humidity may rise. In some places it can be both hot and humid. (a reason Molds love Florida)
The hygro thermometer can be hand held or mounted. They are battery operated. They have large LCD readout which makes reading both temperature and relative humidity values easy. They can also have low battery indicator and come with two keys or buttons for operation. They are very easy to install in enclosures. The measuring range of a typical thermometer is from 10 degrees Celsius or 14 degrees Fahrenheit to a maximum of 60 degrees Celsius or 140 degrees Fahrenheit. It can measure from 20% to 100% relative humidity. The accuracy is plus or minus one degree Celsius or plus or minus one degree Fahrenheit. In relative humidity, it is plus or minus 5% within a certain range and could be higher above or below that range. Measuring relative humidity is not as effective as hygrometers but is still reliable indicators of room condition. The hygro thermometers are not applicable in freezers or other cold storage. They are very applicable in rooms where a lot of heating devices are used such as computer servers, perhaps boilers and other industrial equipment. They are reliable in also indicating the safety in the work environment.
Air sampling with spore traps:
Air samples can be taken and analyzed in a variety of ways. The most common method uses a "spore trap" and is called a "spore trap sample." Spore traps work by having a known volume of air pass impact a sticky surface as it passes through the spore trap sampling device. Most of the particles in the air also impact this sticky surface and consequently adhere to, and are captured on, this sticky surface. Mold spores comprise a subset of these 'particles in the air' and also are captured on the sticky medium inside the spore trap. When the spore trap is sent to the mold testing laboratory for analysis, the mold laboratory opens the spore trap, applies some stains to the sticky surface that the mold spores can absorb, and then identifies and quantifies the types of mold spores captured during the sampling process. There are other methods of mold sampling, including culturing or growing the mold spores captured from the air, but these are less commonly used.
Surface samples can be taken in a variety of ways. The three most common methods are:
Bulk samples. A piece of the sampled area is physically removed and sent to the mold testing laboratory
Swab samples. Something akin to a cotton swab is rubbed across the area being sampled, often a measured area, and subsequently sent to the mold testing laboratory, and
Tape samples. A piece of clear tape is pressed against and removed from the area being sampled, presumably picking up and removing part of any mold that was present on the surface, and then set to the mold testing laboratory for analysis.
After the mold samples arrive at the mold testing laboratory, there are many ways to analyze these mold samples. The most common methods involve transferring relevant sections (or all) of the submitted mold sample onto a glass microscope slide, adding a stain that mold spores can absorb, and then evaluating the sample for evidence of mold growth.
Inspecting for Hidden Mold:
You may suspect hidden mold if a building smells moldy, but you cannot see the source, or if you know there has been water damage and residents are reporting health problems. Mold may be hidden in places such as the back side of dry wall, wallpaper, or paneling, the top side of ceiling tiles, the underside of carpets and pads, etc. Other possible locations of hidden mold include areas inside walls around pipes (with leaking or condensing pipes), the surface of walls behind furniture (where condensation forms), inside ductwork, and in roof materials above ceiling tiles (due to roof leaks or insufficient insulation).
Investigating hidden mold problems
Investigating hidden mold problems may be difficult and will require caution when the investigation involves disturbing potential sites of mold growth. For example, removal of wallpaper can lead to a massive release of spores if there is mold growing on the underside of the paper. If you believe that you may have a hidden mold problem, consider hiring an experienced professional.
Inspection for hidden moisture with a Protimiter (moisture meter):
A protimeter is an advanced instrument used to determine if materials have dampness or moisture content and at what relative level moisture is present. The device is typically hand held and battery powered. When operating, it creates a electromagnetic field/force (EMF) at the detection sensor end tip. Because moisture (water) is conductive, it will affect the EMF producing a signal change. This can then be interpreted into with “percent moisture equivalency in wood” or “percent relative humidity/ moisture content / %RH”. However, in both cases proper calibration and interpretation of values is essential to get empirically correct data. The tool if very good to determine if moisture is or is not present.
When measuring moisture, there will be a level of dampness where excessive moisture causes a problem, decay or breakup of the structure. It is possible to mark when an electronic device indicates ‘Safe - Dry’, ‘Intermediate – At Risk’ and ‘Danger - Wet’. The diagram below details the three bands of dampness.
- Dry (Green band) - indicates that the moisture content is ‘Dry’ and no decay will take place.
- At Risk (Yellow band) – indicates that the moisture content is high and ‘At Risk’ of causing a problem.
- Wet (Red band) – indicates excessive levels of moisture ‘Wet’ and decay is inevitable.
Please note that this chart cannot be utilized to convert %WME into %RH. It is imperative to use the correct test for each reading.
It is important to note that dampness is a hazard long before a material can become visibly damp and damp to the touch. With most materials we can only physically see any problems when the moisture is 85% humidity or higher. This is why it is essential to use a Protimeter moisture meter when surveying for damp.
Moisture inspection using an infrared (IR) camera:
Technology has provided a tool that can be used by investigators, mold remediators, and consultants to detect and help eliminate mold infestations. The technological tool is called Infrared Thermography (IT). IT is a technique that produces an image of invisible (to the human eye) infrared light emitted by objects due to the heat, or lack thereof, in the object called its "thermal condition." The most typical type of thermography camera resembles a typical camcorder and produces a live television picture of heat radiation. More sophisticated cameras can actually measure the temperatures of any object or surface in the image and produce false color images that make interpretation of thermal patterns easier. An image produced by an infrared camera is called a thermogram or sometimes a thermograph.
To understand IT as a tool it is necessary to understand how it works. Thermal or infrared energy is light that is not visible to humans because its wavelength is too long to be detected by the human eye. Thermal or infrared energy (IR) is the part of the electromagnetic spectrum that we perceive as heat. Unlike visible light, in the infrared world, everything with a temperature above absolute zero emits heat. Even very cold objects, like ice cubes, emit infrared. The higher the object's temperature, the greater the IR radiation emitted. Infrared allows people to see what their eyes normally cannot see.
IT cameras produce images of invisible infrared or "heat" radiation. The IT camera can provide precise noncontact temperature measurement capabilities. The existence of moisture—a substance cooler than normal construction materials—can be used to detect conditions that promote mold growth. Mold related problems can be detected before the mold is visible to the eye or detectable by the nose. IT cameras are extremely cost-effective, valuable diagnostic tools in construction related problems of water intrusion and mold growth.
But finding a problem with an infrared camera is not a solution. It is the start of an investigation that will help the property owner or developer stop a problem before it becomes serious. An infrared camera image alone, without accurate temperature measurements, says very little about the condition of a structure or its susceptibility to mold growth. An infrared image without measurement can be misleading because it may visually suggest a problem that does not exist.
Infrared cameras that incorporate temperature measurement allow professionals to make well-informed judgments about the operating condition of a structure. Temperature measurements can be compared with historical operating temperatures, or with infrared readings of similar structures at the same time, to determine if a significant temperature rise will compromise the structural integrity or encourage mold growth.
Used properly, a thermal imaging camera can provide valuable information during moisture assessments, remediation oversight, energy audits, roof and electrical system inspections and water damage investigations. Temperature difference caused by evaporation, radiation, thermal bridging, infiltration/exfiltration, and other sources must all be carefully evaluated.
The inspector trained to properly use the IR camera can read the information to spot suspect areas that are not visible to the naked eye. The findings can later be verified using electronic, data-logging moisture detection equipment and in some cases core samples from the roofs or walls.
The inspector uses thermal imaging and data logging moisture detection equipment to establish that the inspector assesses all areas of concern. The extra verification gives additional assurance that the findings from the IR camera are defensible. All property owners and their insurers faced with a claim alleging mold infestation can find these tools essential to the decision process and proper maintenance of the structure.
When suspect areas are found they can be visually documented using the IR camera. Images, like those obtained from an IR Camera, are easier for a layperson or nontechnical person to understand. Findings from the IR camera can be explained to the property owner or the insurer's personnel combined with the verification obtained by using data-logging moisture detection equipment with time stamp and/or destructive testing.
Using Technology for Mold Claims
The time saved using infrared, and the larger areas covered rapidly by an IR Camera, can save time and money by providing a faster, more efficient and more reliable survey. An IR camera can detect moisture located behind interior walls under the right conditions. The temperature difference created by the presence of moisture on the inside surface of a wall will appear differently than the surrounding area. IR and IT experts recommend that property owners or their insurers should use IR cameras and IT for moisture detection under the following circumstances.
- After any water damage event like a flood, broken water lines, equipment failure, roof leaks, etc.
- Before warranty expiration on new construction. (In many cases, those damp basement walls are explained away as "during construction" moisture. It pays to make sure before warranty expiration.)
- Before acquiring real estate suspected of having hidden moisture damage. (Don't believe the story about the house has been vacant and closed up. Musty odors are caused by moisture.)
- When basement walls are covered by finish materials, and the inspector cannot give a definitive answer on moisture issues.
- When suspected plumbing leaks have occurred from in-slab water supply and/or waste lines.
- When doors, windows, or other openings in the structure are suspected of leaking.
- When performing an energy audit of the building to determine areas of infiltration and exfiltration.
- To determine adequacy of insulation. Wet insulation is a poor insulator but is a great conductor of heat.
- Infrared inspection of the roof can determine potential for ice dams, plugged drains, and water retention that may cause roof damage and/or leakage.
- Locating hidden leakage and/or dampness under resilient flooring.
- Locating wet areas in non-accessible crawlspaces.
Infrared technology is especially useful for inspecting flat roofing systems and synthetic stucco systems, which rarely give any visual clues as to their condition or the location of leaks and moisture retention. Litigation involving synthetic stucco, or exterior insulating finish systems (EIFS), is rampant nationwide. EIFS exterior cladding is blamed by many property owners for retaining moisture behind. The property owners claim that EIFS, because it retains water behind it, promotes mold growth and rotting within exterior wall cavities.
Preventing/Removing Mold and Rot
A mold problem is a moisture problem, so when IR is used to find moisture, and it actually finds moisture, it becomes possible to prevent mold and rot from taking hold or to remove the mold that actually grows.
- What is mold?
- Molds and problems
- How mold samples are analyzed
- Various mold types
- Additional resources about mold