The Dangers of Mold
Molds produce allergens, which are substances that can cause allergic reactions, as well as irritants and, in some cases, potentially toxic substances known as mycotoxins. Inhaling or touching mold or mold spores may cause allergic reactions in sensitive individuals. Allergic responses include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin
Carpet at Risk
Carpeting is an area of the home that can be at high risk for mold growth. In order to grow, mold needs moisture, oxygen, a food source, and a surface to grow on. Mold spores are commonly found naturally in the air. If spores land on a wet or damp spot indoors that contains dust for them to feed on, mold growth will soon follow. Wall-to-wall carpeting, as well as area rugs, can provide an ample breeding ground for mold if conditions are right. At especially high risk for mold growth are carpeting located below ground level in basements, carpet in commonly moist or damp climates, and carpet that has been wet for any period of time.
Identifying Mold in Carpeting
Just because mold is not immediately apparent or visible on a carpet's surface does not mean that mold growth is not in progress. In fact, mold will probably only be visible on the surface of carpets in unusually severe cases of growth, such as carpet damaged in flooding that has remained wet for some time. InsideOut Inspections can detect specific types of mold spores by using state of the art equipment to pull air samples from your home. The following are some examples of identifiable instances where mold growth has occurred or is likely to occur:
The best method for combating mold is to not allow mold growth in the first place. The best way to do so is by ensuring that conditions conducive to growth do not exist. Below are some ways to prevent mold growth in carpets.
In many cases, if mold has grown on carpet, cleaning will not be possible. If growth has occurred on more than one area of the carpet, or if there is a large area of growth, the carpet will probably need to be replaced.
About 24 hours is a reasonable amount of time to wait after testing to be sure that wider cleaning will not discolor or damage the carpet.
Another option in instances where mold growth is not widespread is to remove the ruined section of the carpet. If cleaning has been attempted unsuccessfully, the area of mold growth may be removed and replaced with a patch of similar carpet. Of course, this will only work in situations where aesthetics are not a big concern, since exactly matching the patch to the original carpet may be difficult and the seam may be visible. If mold has grown in more than one area of the carpet, or if the area of growth is larger than a couple of feet, this will probably not be an effective method of mold removal.
As with all areas of the interior at risk for mold growth, prevention is the best method of control for carpet mold. Eliminating high-moisture conditions and preventing the risk of flooding or standing water will reduce the possibility of growth. Inspectors will want to know where to look for and how to identify mold growth in carpeting. It is also helpful to know how to determine if carpet should be replaced, or whether there is a possibility of cleaning and saving it.
Carpeted bathrooms are bathrooms that have carpeted floors instead of traditional floor surfaces, such as tile or vinyl. Despite their tendency to foster mold and bacteria, carpets are sometimes installed in residential bathrooms for aesthetic purposes.
Disadvantages of Carpets in Bathrooms
The pad beneath the carpet may soak up large amounts of moisture. Some of the common ways that carpets may come into contact with moisture in bathrooms include:
In addition to potential mold growth beneath the carpet, bacteria can accumulate in carpeting that surrounds the toilet. Bacteria are contained in urine, which can be accidentally deflected onto the carpet.
The following are recommendations that InterNACHI inspectors can pass on to clients who are experiencing urine- or moisture-related problems with their bathroom carpet:
In summary, carpets installed in bathrooms can trap moisture and urine, substances that can cause structural damage and health problems.
Ceramic tile and stone are popular flooring materials, but each is subject to damage if not properly maintained.
In summary, ceramic and stone can be superb flooring materials, but water, acid, improper installation, and other adverse conditions may create defects.
Condensation, also called sweating, forms on building materials when the temperature drops below the dew point, which is the temperature at which droplets of water vapor are forced so closely together that they coalesce into liquid water. Because of their characteristic thermal conductivity, components made of metal are usually the first places where condensation will appear in a building.
Where does condensation typically form?
Metals also vary in their thermal conductivity. Thus, they tend to cause water vapor to condense. Inspectors can be aided by a rule of thumb that states that a metal’s ability to transfer heat (and, therefore, create condensation) is roughly equal to that metal’s electrical conductivity. Electricians and some inspectors may know that, of all metals, copper is the second-best conductor of heat and electricity, meaning that it’s more likely to respond to a brief burst of cool water or air than other metals, such as steel or lead. The metal with the greatest conductivity is silver, but it’s far too expensive to be used in ordinary construction.
In summary, condensation will form on cold surfaces if certain precautions are not taken. If left unmitigated, it can lead to moisture-related problems that can affect structural components, as well as the occupants' health.
Humidifiers are devices that humidify air so that building occupants are comfortable. Central humidifiers are hard-wired into a house’s plumbing and forced-air heating systems.
What is humidity?
Humidity refers to the amount of moisture in the air. “Relative humidity” signifies the amount of moisture in the air relative to the maximum amount of water the air can contain before it becomes saturated. This maximum moisture count is related to air temperature in that the hotter the air is, the more moisture it can hold. For instance, if indoor air temperature drops, relative humidity will increase.
How do central air humidifiers work?
Central air humidifiers are integrated into the forced-air heating system so that they humidify air while it is being heated. The water that is used by the device is pumped automatically into the humidifier from household plumbing, unlike portable humidifiers, which require the user to periodically supply water to the device. Humidifiers are available in various designs, each of which turns liquid water into water vapor, which is then vented into the house at an adjustable rate.
Why humidify air?
Certain airborne pathogens, such as those that cause the flu, circulate easier in dry air than in moist air. Moist air also seems to soothe irritated, inflamed airways. For someone with a cold and thick nasal secretions, a humidifier can help thin out the secretions and make breathing easier.
Central Humidifier Dangers
Humidifiers can cause various diseases. The young, elderly and infirm may be particularly at risk to contamination from airborne pollutants, such as bacteria and fungi. These can grow in humidifiers and get into the air by way of the vapor where it can be breathed in. Some of the more common diseases and pathogens transmitted by humidifiers are:
Other tips that InterNACHI inspectors can pass on to their clients:
In summary, central humidifiers are used to humidify air to make it more comfortable, but they can cause health problems and building damage if they are not properly maintained.
Chimneys are among the heaviest and most structurally vulnerable of all exterior components of a building. Accidents caused by their collapse can lead to death. A collapse can also cause costly structural damage to the building and its surroundings. Inspection, maintenance and preparedness are critical safeguards against chimney collapse.
Chimneys should be inspected for the following defects:
Homeowners should contact their local building departments to obtain required permits before starting any significant construction that may affect the chimney structure and/or its supports.
In addition to collapse hazards, leaning chimneys can also make using the fireplace dangerous. Hearth cracks, side cracks in the fireplace, openings around the fireplace, and chimney damage all present the risk that sparks or smoke will enter the living space or building cavities. Check for evidence of fireplace movement.
Commercial chimney collapses are rare, but they deserve mention due to the devastation they cause. In one terrible incident in central India, more than 100 workers were killed when a 900-foot (275-meter) tall chimney collapsed on a construction site. One of the worst construction site disasters in recent history, the collapse was blamed on heavy rain. While safety standards are generally more stringent outside of India, commercial chimneys everywhere require inspection.
In summary, chimneys should be inspected to prevent deadly, expensive collapses.
Bathroom ventilation systems are designed to exhaust odors and moist air to the home's exterior. Typical systems consist of a ceiling fan unit connected to a duct that terminates at the roof.
The fan may be controlled in one of several ways:
to the fan because of its static charge. Inspectors should comment on dirty fan covers.
Ventilation systems should be installed in all bathrooms. This includes bathrooms with windows, since windows will not be opened during the winter in cold climates.
The following conditions indicate insufficient bathroom ventilation:
The most common defect related to bathroom ventilation systems is improper termination of the duct. Vents must terminate at the home exterior.
The most common improper terminations locations are:
Improperly terminated ventilation systems may appear to work fine from inside the bathroom, so the inspector may have to look in the attic or on the roof. Sometimes, poorly installed ducts will loosen or become disconnected at joints or connections.
Ducts that leak or terminate in attics can cause problems from condensation. Warm, moist air will condense on cold attic framing, insulation and other materials. This condition has the potential to cause health and/or decay problems from mold, or damage to building materials, such as drywall. Moisture also reduces the effectiveness of thermal insulation.
Perhaps the most serious consequence of an improper ventilation setup is the potential accumulation of mold in attics or crawlspaces. Mold may appear as a fuzzy, thread-like, cobwebby fungus, although it can never be identified with certainty without being lab-tested. Health problems caused by mold are related to high concentrations of spores in indoor air. Spores are like microscopic seeds, released by mold fungi when they reproduce. Every home has mold. Moisture levels of about 20% in materials will cause mold colonies to grow. Inhaling mold spores can cause health problems in those with asthma or allergies, and can cause serious or fatal fungal infections in those with lung disease or compromised immune systems.
Mold is impossible to identify visually and must be tested by a lab in order to be confidently labeled. Inspectors should refrain from calling anything “mold” but should refer to anything that appears as mold as a material that “appears to be microbial growth.” Inspectors should include in their report, and in the inspection agreement signed by the client, a disclaimer clearly stating that the General Home Inspection is an inspection for safety and system defects, not a mold inspection.
Decay, which is rot, is also caused by fungi. Incipient or early decay cannot be seen. By the time decay becomes visible, affected wood may have lost up to 50% of its strength.
In order to grow, mold fungi require the following conditions to be present:
If insufficient levels of any of these requirements exist, all mold growth will stop and fungi will go dormant. Most are difficult to actually kill.
Even though mold growth may take place in the attic, mold spores can be sucked into the living areas of a residence by low air pressure. Low air pressure is usually created by the expulsion of household air from exhaust fans in bathrooms, dryers, kitchens and heating equipment.
The following tips are helpful, although not required. Ventilation ducts should:
Anti-scald valves, also known as tempering valves and mixing valves, mix cold water in with outgoing hot water so that the hot water that leaves a fixture is not hot enough to scald a person.
Unwanted temperature fluctuations are an annoyance and a safety hazard. When a toilet is flushed, for instance, cold water flows into the toilet’s tank and lowers the pressure in the cold-water pipes. If someone is taking a shower, they will suddenly feel the water become hotter as less cold water is available to the shower valve. By the same principle, the shower water will become colder when someone in the house uses the hot-water faucet. This condition is exacerbated by plumbing that’s clogged, narrow, or installed in showers equipped with low-flow or multiple showerheads. A sudden burst of hot water can cause serious burns, particularly in young children, who have thinner skin than adults. Also, a startling thermal shock – hot or cold – may cause a person to fall in the shower as he or she scrambles on the slippery surface to adjust the water temperature. The elderly and physically challenged are at particular risk.
Anti-scald valves mitigate this danger by maintaining water temperature at a safe level, even as pressures fluctuate in water supply lines. They look similar to ordinary shower and tub valves and are equipped with a special diaphragm or piston mechanism that immediately balances the pressure of the hot- and cold-water inputs, limiting one or the other to keep the temperature within a range of several degrees. As a side effect, the use of an anti-scald valve increases the amount of available hot water, as it is drawn more slowly from the water heater. Inspectors and homeowners may want to check with the authority having jurisdiction (AHJ) to see if these safety measures are required in new construction in their area.
Installation of anti-scald valves is typically simple and inexpensive. Most models are installed in the hot-water line and require a cold-water feed. They also require a swing check valve on the cold-water feed line to prevent hot water from entering the cold-water system. They may be installed at the water heater to safeguard the plumbing for the whole building, or only at specific fixtures.
The actual temperature of the water that comes out of the fixture may be somewhat different than the target temperature set on the anti-scald valve. Such irregularities may be due to long, uninsulated plumbing lines or defects in the valve itself. Users may fine-tune the valve with a rotating mechanism that will allow the water to become hotter or colder, depending on which way it’s turned. Homeowners may contact an InterNACHI inspector or a qualified plumber if they have further questions or concerns.
In summary, anti-scald valves are used to reduce water temperature fluctuations that may otherwise inconvenience or harm unsuspecting building occupants.
Kickout flashing, also known as diverter flashing, is a special type of flashing that diverts rainwater away from the cladding and into the gutter. When installed properly, they provide excellent protection against the penetration of water into the building envelope.
The kickout was never installed.
The following are locations where kickout flashing is critical:
In summary, kickout flashing should be present and properly installed in order to direct rainwater away from the cladding.
An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow from draining. As water backs up behind the dam, it can leak through the roof and cause damage to walls, ceilings, insulation and other areas.
How do ice dams form?
Ice dams are formed by an interaction between snow cover, outside temperatures, and heat lost through the roof. Specifically, there must be snow on the roof, warm portions of the upper roof (warmer than 32° F), and cold portions of the lower roof (at freezing or below). Melted snow from the warmer areas will refreeze when it flows down to the colder portions, forming an ice dam.
Although the primary contributor to snow melting is heat loss from the building's interior, solar radiation can also provide sufficient heat to melt snow on a roof. For example, in southern Canada, enough sunlight can be transmitted through 6 inches (150 mm) of snow cover on a clear and sunny day to cause melting at the roof's surface even when the outside temperature is 14° F (-10° C), with an attic temperature of 23° F (-5° C).
Gutters do not cause ice dams to form, contrary to popular belief. Gutters do, however, help concentrate ice from the dam in a vulnerable area, where parts of the house can peel away under the weight of the ice and come crashing to the ground.
Problems Associated with Ice Dams
Ice dams are problematic because they force water to leak from the roof into the building envelope. This may lead to:
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