Between approximately 1965 and 1973, single-strand aluminum wiring was sometimes substituted for copper branch-circuit wiring in residential electrical systems due to the sudden escalating price of copper. After a decade of use by homeowners and electricians, inherent weaknesses were discovered in the metal that lead to its disuse as a branch wiring material. Although properly maintained aluminum wiring is acceptable, aluminum will generally become defective faster than copper due to certain qualities inherent in the metal. Neglected connections in outlets, switches and light fixtures containing aluminum wiring become increasingly dangerous over time. Poor connections cause wiring to overheat, creating a potential fire hazard. In addition, the presence of single-strand aluminum wiring may void a home’s insurance policies. Inspectors may instruct their clients to talk with their insurance agents about whether the presence of aluminum wiring in their home is a problem that requires changes to their policy language.
 
Facts and Figures 

• On April, 28, 1974, two people were killed in a house fire in Hampton Bays, New York. Fire officials determined that the fire was caused by a faulty aluminum wire connection at an outlet. 
• According to the Consumer Product Safety Commission (CPSC), "Homes wired with aluminum wire manufactured before 1972 ['old technology' aluminum wire] are 55 times more likely to have one or more connections reach "Fire Hazard Conditions" than is a home wired with copper." 

Aluminum as a Metal
Aluminum possesses certain qualities that, compared with copper, make it an undesirable material as an electrical conductor. These qualities all lead to loose connections, where fire hazards become likely. These qualities are as follows: 

• higher electrical resistance. Aluminum has a high resistance to electrical current flow, which means that, given the same amperage, aluminum conductors must be of a larger diameter than would be required by copper conductors. 
• less ductile. Aluminum will fatigue and break down more readily when subjected to bending and other forms of abuse than copper, which is more ductile. Fatigue will cause the wire to break down internally and will increasingly resist electrical current, leading to a buildup of excessive heat. 
• galvanic corrosion.  In the presence of moisture, aluminum will undergo galvanic corrosion when it comes into contact with certain dissimilar metals. 
• oxidation. Exposure to oxygen in the air causes deterioration to the outer surface of the wire. This process is called oxidation. Aluminum wire is more easily oxidized than copper wire, and the compound formed by this process – aluminum oxide – is less conductive than copper oxide. As time passes, oxidation can deteriorate connections and present a fire hazard.   
• greater malleability. Aluminum is soft and malleable, meaning it is highly sensitive to compression. After a screw has been over-tightened on aluminum wiring, for instance, the wire will continue to deform or “flow” even after the tightening has ceased. This deformation will create a loose connection and increase electrical resistance in that location. 
• greater thermal expansion and contraction. Even more than copper, aluminum expands and contracts with changes in temperature. Over time, this process will cause connections between the wire and the device to degrade. For this reason, aluminum wires should never be inserted into the “stab,” “bayonet” or “push-in” type terminations found on the back of many light switches and outlets. 
• excessive vibration. Electrical current vibrates as it passes through wiring. This vibration is more extreme in aluminum than it is in copper, and, as time passes, it can cause connections to loosen. 

Identifying Aluminum Wiring

• Aluminum wires are the color of aluminum and are easily discernible from copper and other metals. 
• Since the early 1970s, wiring-device binding terminals for use with aluminum wire have been marked CO/ALR, which stands for “copper/aluminum revised." 
• Look for the word "aluminum" or the initials "AL" on the plastic wire jacket. Where wiring is visible, such as in the attic or electrical panel, inspectors can look for printed or embossed letters on the plastic wire jacket. Aluminum wire may have the word "aluminum," or a specific brand name, such as "Kaiser Aluminum," marked on the wire jacket. Where labels are hard to read, a light can be shined along the length of the wire. 
• When was the house built? Homes built or expanded between 1965 and 1973 are more likely to have aluminum wiring than houses built before or after those years.

Options for Correction
Aluminum wiring should be evaluated by a qualified electrician who is experienced in evaluating and correcting aluminum wiring problems. Not all licensed electricians are properly trained to deal with defective aluminum wiring. The CPSC recommends the following two methods for correction for aluminum wiring:

• Rewire the home with copper wire. While this is the most effective method, rewiring is expensive and impractical, in most cases. 
• Use copalum crimps. The crimp connector repair consists of attaching a piece of copper wire to the existing aluminum wire branch circuit with a specially designed metal sleeve and powered crimping tool. This special connector can be properly installed only with the matching AMP tool. An insulating sleeve is placed around the crimp connector to complete the repair. Although effective, they are expensive (typically around $50 per outlet, switch or light fixture).

Although not recommended by the CPSC as methods of permanent repair for defective aluminum wiring, the following methods may be considered: 

• application of anti-oxidant paste. This method can be used for wires that are multi-stranded or wires that are too large to be effectively crimped. 
• pigtailing. This method involves attaching a short piece of copper wire to the aluminum wire with a twist-on connector. the copper wire is connected to the switch, wall outlet or other termination device. This method is only effective if the connections between the aluminum wires and the copper pigtails are extremely reliable. Pigtailing with some types of connectors, even though Underwriters Laboratories might presently list them for the application, can lead to increasing the hazard. Also, beware that pigtailing will increase the number of connections, all of which must be maintained. Aluminum Wiring Repair (AWR), Inc., of Aurora, Colorado, advises that pigtailing can be useful as a temporary repair or in isolated applications, such as the installation of a ceiling fan. 
• CO/ALR connections. According to the CPSC, these devices cannot be used for all parts of the wiring system, such as ceiling-mounted light fixtures or permanently wired appliances and, as such, CO/ALR connections cannot constitute a complete repair. Also, according to AWR, these connections often loosen over time. 
• alumiconn. Although AWR believes this method may be an effective temporary fix, they are wary that it has little history, and that they are larger than copper crimps and are often incorrectly applied.  
• Replace certain failure-prone types of devices and connections with others that are more compatible with aluminum wire. 
• Remove the ignitable materials from the vicinity of the connections. 

In summary, aluminum wiring can be a fire hazard due to inherent qualities of the metal. Inspectors should be capable of identifying this type of wiring.

​Aluminum siding is generally in decline as an exterior cladding material because vinyl siding and other materials have become more popular choices.  However, it is still among the most common forms of siding found today.  It provided many advantages over other materials when it was introduced in the 1940s.  It was installed on many affordable homes through the 1970s.  
 
InterNACHI inspectors will encounter aluminum siding on many home exteriors and can benefit from knowing more about this common form of exterior cladding.  Homeowners may be interested in the drawbacks of this material, as well as some of the advantages it still provides in certain situations today.
 History and Manufacturing
Aluminum siding is made from aluminum coil stock, which is chemically coated to protect the metal and then painted for further protection, as well as aesthetics.  After coating, the siding is baked for durability, with enamel often added to create desired textures.
One of the earliest architectural uses of aluminum came in the 1920s when it was used to produce ornamental spandrel panels for the Chrysler Building and the Empire State Building in New York City.  By the 1940s, aluminum siding was being produced for use on residential structures, and quickly became popular due to the advantages it provided over other materials in use at the time.  A Pennsylvania subdivision built in 1947 was reportedly the first housing project to use solely aluminum siding.  
Its popularity remained fairly steady until the 1970s, during the energy crisis.  Aluminum siding requires a great deal of energy for production, as well as consumption of a significant amount of raw materials.  These factors largely contributed to its decline in use as other forms of exterior cladding became more popular.
Pros and Cons
Although aluminum siding is seeing less use these days, it possesses some attributes that may be seen as advantageous over other materials in certain situations.  There are also some areas where aluminum siding doesn’t stack up quite as well as other options.  Here are some pros and cons to consider with aluminum siding.
Advantages

• Aluminum siding is very lightweight.
• It is fairly durable.  When properly maintained, it can last from 40 years to the life of the structure.  
• It accepts the application of paint well and can be painted any desired color.
• Aluminum siding does not rust.
• It is fireproof.  In case of fire, it will not burn or melt like other claddings.
• It is waterproof.  When properly installed, it provides excellent water-resistant capabilities for exterior walls.
• Since aluminum siding contains no organic material, it will not rot or serve as a source of food for termites.
• An enamel coating baked onto the surface of the siding can mimic the look of other materials, such as wood grain, which gives the siding a more traditional look.
• Aluminum siding is recyclable.

Disadvantages

• Aluminum siding can dent easily, and the damaged area may be difficult to repair or replace.  Many siding manufacturers offer a thin backing board of insulation that fits behind each panel.  This backing can help protect against dents. 
• Although the siding takes the application of paint well, it may need to be repainted every five to 10 years.  If any oxidization has occurred, it must be removed before new paint is applied, which can make for a labor-intensive process.  In general, repainting aluminum siding requires preparation similar to repainting a car.
• Scratches in the siding will usually be immediately noticeable and unsightly because they can reveal the metal surface below the paint.
• Although aluminum will not rust because it contains no iron, as opposed to steel siding, it can corrode.  It can also be stained by the rust on adjacent materials.
• The sound of rain and hail striking it can be loud enough that some people avoid using it for this reason alone.
• Aluminum siding has gone out of style aesthetically, and is generally considered less desirable than both more traditional and newer, modern forms of exterior cladding.
• The production of aluminum siding requires a large amount of energy and raw materials.

Inspection Tips
Here are some things that inspectors can keep in mind while examining exterior walls clad in aluminum siding:

• Since metal siding can conduct electricity, some jurisdictions require that the siding be grounded as a safety measure.  Inspectors can check with the local authority having jurisdiction (AHJ) to find out if grounding is a requirement.
• Aluminum siding can be distinguished from vinyl siding by visual inspection.  Any dents in the siding are a clue that it is aluminum, as opposed to vinyl, which may show cracks or breaks.  
• Lightly tapping on the siding can also help determine what the material is.  Aluminum has a slightly hollow and metallic sound when struck.
• Distinguishing between aluminum and steel siding can be more difficult and may require the use of a magnet, which will interact with steel but not aluminum.  Rust spots are another sign that the siding is steel.
• Properly installed aluminum siding should not be in contact with the ground.  The AHJ can be consulted for the minimum required clearance.  
• If the siding has been installed in contact with the ground or below ground level, outward bulging at the bottom can be an indication that the building sills and/or lower walls have been damaged by rot or pests.

Aluminum siding was very popular in the latter part of the 20th century and is still installed on many homes across the United States today.  InterNACHI inspectors who know more about this common type of exterior cladding will be at an advantage when inspecting exteriors and answering clients’ questions.

​Taking air samples during a mold inspection is important for several reasons.  Mold spores are not visible to the naked eye, and the types of mold present can often be determined through laboratory analysis of the air samples.  Having samples analyzed can also help provide evidence of the scope and severity of a mold problem, as well as aid in assessing human exposure to mold spores.  After remediation, new samples are typically taken to help ensure that all mold has been successfully removed. 
 Air samples can be used to gather data about mold spores present in the interior of a house.  These samples are taken by using a pump that forces air through a collection device which catches mold spores.  The sample is then sent off to a laboratory to be analyzed.  InterNACHI inspectors who perform mold inspections often utilize air sampling to collect data, which has become commonplace.
Air-Sampling Devices
There are several types of devices used to collect air samples that can be analyzed for mold.  Some common examples include:

• impaction samplers that use a calibrated air pump to impact spores onto a prepared microscope slide;
• cassette samplers, which may be of the disposable or one-time-use type, and also employ forced air to impact spores onto a collection media; and
• airborne-particle collectors that trap spores directly on a culture dish.  These may be utilized to identify the species of mold that has been found.

When and When Not to Sample
Samples are generally best taken if visual, non-invasive examination reveals apparent mold growth or conditions that could lead to growth, such as moisture intrusion or water damage.  Musty odors can also be a sign of mold growth.  If no sign of mold or potential for mold is apparent, one or two indoor air samples can still be taken, at the discretion of the inspector and client, in the most lived-in room of the house and at the HVAC unit.   
Outdoor air samples are also typically taken as a control for comparison to indoor samples.  Two samples -- one from the windward side and one from the leeward side of the house -- will help provide a more complete picture of what is in the air that may be entering the house through windows and doors at times when they are open.  It is best to take the outdoor samples as close together in time as possible to the indoor samples that they will be compared with.
InterNACHI inspectors should avoid taking samples if a resident of the house is under a physician’s care for mold exposure, if there is litigation in progress related to mold on the premises, or if the inspector’s health or safety could be compromised in obtaining the sample.  Residential home inspectors also should not take samples in a commercial or public building.
Where to Sample and Ideal Conditions
In any areas of a house suspected or confirmed to have mold growth, air samples can be taken to help verify and gather more information.  Moisture intrusion, water damage, musty odors, apparent mold growth, or conditions conducive to mold growth are all common reasons to gather an air sample.  Samples should be taken near the center of the room, with the collection device positioned 3 to 6 feet off the ground. 
Ten minutes is an adequate amount of time for the air pump to run while taking samples, but this can be reduced to around five minutes if there is a concern that air movement from a lot of indoor activity could alter the results.  The sampling time can be reduced further if there is an active source of dust, such as from ongoing construction.
Sampling should take place in livable spaces within the house under closed conditions in order to help stabilize the air and allow for reproducibility of the sampling and measurement.  While the sample is being collected, windows and exterior doors should be kept shut other than for normal entry and exit from the home.  It is best to have air exchangers (other than a furnace) or fans that exchange indoor-outdoor air switched off during sampling.
Weather conditions can be an important factor in gathering accurate data. Severe thunderstorms or unusually high winds can affect the sampling and analysis results.  High winds or rapid changes in barometric pressure increase the difference in air pressure between the interior and exterior, which can increase the variability of airborne mold-spore concentration.  Large differences in air pressure between the interior and exterior can cause more airborne spores to be sucked inside, skewing the results of the sample.  
Difficulties and Practicality of Air Sampling
It is helpful to think of air sampling as just one tool in the tool belt when inspecting a house for mold problems.  An air sample alone is not enough to confirm or refute the existence of a problem, and such testing needs to be accompanied by visual inspection and other methods of data collection, such as a surface sample.  Indoor airborne spore levels can vary according to several factors, and this can lead to skewed results if care is not taken to set up the sampling correctly.  Also, since only spores are collected with an air sample and may actually be damaged during collection, identification of the mold type can be more difficult than with a sample collected with tape or a cultured sample. 
Air samples are good for use as a background screen to ensure that there isn’t a large source of mold not yet found somewhere in a home.  This is because they can detect long chains of spores that are still intact.  These chains normally break apart quickly as they travel through the air, so a sample that reveals intact chains can indicate that there is mold nearby, possibly undiscovered during other tests and visual examination.  
In summary, when taken under controlled conditions and properly analyzed, air samples for mold are helpful in comparing relative particle levels between a problem and a control area.  They can also be crucial for comparing particle levels and air quality in an area before and after mold remediation.

"Aging in place" is the phenomenon describing senior citizens' ability to live independently in their homes for as long as possible. Those who age in place will not have to move from their present residence in order to secure necessary support services in response to their changing needs. 
 The Baby Boomers
As the baby boomers age, the 60+ population will spike from roughly 45 million in recent years to more than 70 million by 2020. Research shows that baby boomers’ expectations of how they will receive care differ from that of their parents’ generation.  Overwhelmingly, they will seek care in their own homes and will be less likely to move into congregate living settings.
Why do many senior citizens prefer to age in place? 
Nursing homes, to many, represent a loss of freedom and a reduced quality of life. Here are a few good reasons why these fears are justified:

• In 2007, inspectors received 37,150 complaints about conditions in nursing homes. Roughly one-fifth of the complaints verified by federal and state authorities involved the abuse or neglect of patients. Specific problems included infected bedsores, medication mix-ups, poor nutrition, and other forms of neglect. 
• The proportion of nursing homes cited for deficiencies ranged from 76% in Rhode Island to as high as 100% in Alaska, Idaho, Wyoming and Washington, D.C. 
• Many cases have been exposed in which nursing homes billed Medicare and Medicaid for services that were not provided. 
• A significant percentage of nursing homes had deficiencies that caused immediate jeopardy or actual harm to patients.

Aging-in-Place Inspections  
Inspectors may recommend corrections and adaptations to the home to improve maneuverability, accessibility, and safety for elderly occupants. Some such alterations and recommendations for a home are as follows:
Appliances:

• • microwave oven in wall or on counter; 
  • refrigerator and freezer side by side; 
  • side-swing or wall oven; 
  • controls that  are easy to read; 
  • raised washing machine and dryer; 
  • front-loading washing machines; 
  • raised dishwasher with push-button controls; 
  • stoves having electric cooktops with level burners for safely transferring between the burners; front controls and downdraft feature to pull heat away from user; light to indicate when surface is hot; and 
  • replace old stoves with induction cooktops to help prevent burns.

Bathroom:

• • fold-down seat installed in the shower; 
  • adjustable showerheads with 6-foot hose; 
  • light in shower stall; 
  • wall support, and provision for adjustable and/or varied-height counters and removable base cabinets; 
  • contrasting color edge border at countertops; 
  • at least one wheelchair-maneuverable bath on main level; 
  • bracing in walls around tub, shower, shower seat and toilet for installation of grab bars; 
  • if stand-up shower is used in main bath, it is curbless and wide; 
  • low bathtub; 
  • toilet higher than standard toilet, or height-adjustable; 
  • design of the toilet paper holder allows rolls to be changed with one hand; 
  • wall-hung sink with knee space and panel to protect user from pipes; and
  • slip-resistant flooring in bathroom and shower.

Counters:

• • base cabinet with roll-out trays; 
  • pull-down shelving; 
  • wall support, and provision for adjustable and/or varied-height counters and removable base cabinets; 
  • upper wall cabinetry lower than conventional height; 
  • accented stripes on edge of countertops to provide visual orientation to the workspace; 
  • counter space for dish landing adjacent to or opposite all appliances; 
  • glass-front cabinet doors; and
  • open shelving for easy access to frequently used items.

Exterior:

• • low-maintenance exterior (vinyl, brick, etc); and 
  • low-maintenance shrubs and plants.

Entry:

• • sensor light at exterior no-step entry focusing on the front-door lock; 
  • non-slip flooring in foyer; 
  • accessible path of travel to the home; 
  • at least one no-step entry with a cover; 
  • entry door sidelight or high/low peep hole viewer; sidelight should provide both privacy and safety; 
  • doorbell in accessible location; and
  • a surface on which to place packages while opening door.

Electrical, Lighting, Safety and Security:

• • install new smoke and CO detectors; 
  • install automated lighting, an emergency alert system, or a video-monitoring system; 
  • easy-to-see and read thermostats; 
  • light switches by each entrance to halls and rooms; 
  • light receptacles with at least two bulbs in vital places (exits, bathroom); 
  • light switches, thermostats and other environmental controls placed in accessible locations no higher than 48 inches from floor; 
  • move electrical cords out of the flow of traffic; 
  • replace standard light switches with rocker or touch-light switches; and
  • pre-programmed thermostats.

Faucets:

• • thermostatic or anti-scald controls; 
  • lever handles or pedal-controlled; and
  • pressure-balanced faucets.

Flooring:

• • if carpeted, use low-density with firm pad; 
  • smooth, non-glare, slip-resistant surfaces, interior and exterior; and
  • color and texture contrast to indicate change in surface levels.

Hallways:

• • wide; 
  • well-lit; and
  • fasten down rugs and floor runners, and remove any that are not necessary.

Heating, Ventilation and Air Conditioning:

• • install energy-efficient units; 
  • HVAC should be designed so filters are easily accessible; and 
  • windows that can be opened for cross-ventilation and fresh air.

Miscellaneous:

• • 30-inch by 48-inch clear space at appliances, or 60-inch diameter clear space for turns; 
  • multi-level work areas to accommodate cooks of different heights; 
  • loop handles for easy grip and pull; 
  • pull-out spray faucet; 
  • levered handles; 
  • in multi-story homes, laundry chute or laundry facilities in master bedroom; 
  • open under-counter seated work areas; and
  • placement of task lighting in appropriate work areas.

Overall Floor Plan:

• • main living on a single story, including full bath; 
  • 5-foot by 5-foot clear turn space in living area, kitchen, a bedroom and a bathroom; and
  • no steps between rooms on a single level.

Reduced Maintenance and Convenience Features:

• • easy-to-clean surfaces; 
  • built-in recycling system; 
  • video phones; 
  • central vacuum; 
  • built-in pet feeding system; and
  • intercom system.

Stairways, Lifts and Elevators:

• • adequate hand rails on both sides of stairway; 
  • residential elevator or lift; and
  • increased visibility of stairs through contrast strip on top and bottom stairs, and color contrast between treads and risers on stairs with use of lighting.

Storage:

• • lighting in closets; 
  • adjustable closet rods and shelves; and
  • easy-open doors that do not obstruct access.

Windows:

• • plenty of windows for natural light; 
  • low-maintenance exterior and interior finishes; 
  • lowered windows, or taller windows with lower sill height; and
  • easy-to-operate hardware.

Advice for those who wish to age in place:

• Talk with family members about your long-term living preferences. Do you want to downsize to a smaller single-family home, or do you plan to stay put in your traditional family home?
• Take a look at your finances and retirement funds. With your current savings and assets, will you be able to pay for home maintenance? Consider starting a separate retirement savings account strictly for home maintenance. 
• Remodel your home before your mobility becomes limited. As you age, changes in mobility, hearing, vision and overall health and flexibility will affect how easily you function in your home. Consider making your home “age-friendly” as a phased-in and budgeted home improvement, rather than waiting until you need many modifications at a time due to a health crisis. 
• If you decide before you retire that you want to live in your current home through the remainder of life, consider paying for “big ticket – long life” home projects while you still have a healthy income. Such items may include having the roof assessed or replaced, replacing and upgrading the water heater or cooling unit, completing termite inspections and treatment, having a septic tank inspection and replacement, as needed, and purchasing a riding lawn mower. 
• InterNACHI advocates healthy living, as it plays a vital role in your ability to age in place. Most seniors leave their homes due to functional and mobility limitations that result from medical crises, and an inability to pay for support to stay with them in their home. Effectively managing health risks and maintaining a healthy lifestyle can help you stay strong, age well, and live long at your own home.

In summary, aging in place is a way by which senior citizens can avoid being dependent on others due to declining health and mobility.

​What are AFCIs? 
 
Arc-fault circuit interrupters (AFCIs) are special types of electrical receptacles (or outlets) and circuit breakers designed to detect and respond to potentially dangerous electrical arcs in home branch wiring.
 
What are AFCI testers or indicators?
 
AFCI tester indicators (sometimes called AFCI testers) are portable devices designed to test AFCI functionality. They create waveform patterns similar to those produced by actual arc faults, thereby causing working AFCIs to trip. AFCI indicators are considerably larger and more expensive (by several hundred dollars) than  ground-fault circuit interrupter (GFCI) indicators and are of questionable effectiveness. For these reasons, they are not used as widely as GFCI indicators.
 
Why are AFCI indicators important?
 
While an AFCI circuit breaker comes with a test button that performs a role similar to a portable AFCI indicator, this button cannot test for arc faults within individual portions of the branch circuit. An AFCI indicator, however, can test any individual receptacle within the branch. InterNACHI inspectors should use AFCI indicators to inspect receptacles observed and deemed to be AFCI-protected.
 
How do they work?
 
AFCI indicators should be inserted directly into the receptacle. Some AFCI indicators, such as the popular #61-165 model produced by Ideal™, offer a number of testing options. This indicator creates eight to 12 pulses of 106 to 141 amp charges in less than a second which should be recognized by the AFCI as a dangerous arc and cause it to open the circuit that it serves. The indicator can also test for nuisance tripping, the annoying tendency of an AFCI to open its circuit when it detects a safe, shared neutral connection. For this test, it produces a 300mA arc that should not cause the AFCI to trip. Some AFCI indicators conveniently incorporate a GFCI indicator into their design.
 
AFCI indicators are somewhat larger than GFCI indicators but they are operated in the same way. An inspector simply inserts one into a receptacle and navigates the menu in order to produce the desired electric current. The user will know that the circuit in question has been tripped if the AFCI device loses power. If this occurs following an AFCI test, the AFCI is functioning properly. The user should then go to the electrical panel to reset the AFCI breaker. If the test results in the failure of an AFCI breaker to open the circuit, then a qualified electrician should be contacted.
 
How effective are they?
 
It is important to understand the distinction between an AFCI indicator and the test button on an AFCI device. The latter produces an actual arc fault and can be relied upon to assess the functionality of the AFCI. An indicator, by contrast, creates waveforms that are not true arcs but are characteristic of them and are thus not a completely reliable measure of an AFCI’s functionality. As a result of this distinction, an indicator might not cause a perfectly functional AFCI to trip. Although commonly called testers, it is more appropriate to refer to them as indicators, despite terminology that often appears in AFCI “tester” user guides.
 
Underwriters Laboratories, a product-testing organization that develops product standards, requires AFCI indicators to include the following information detailing this limitation in their product manuals:
CAUTION:  AFCIs recognize characteristics unique to arcing, and AFCI indicators produce characteristics that mimic some forms of arcing. Because of this, the indicator may give a false indication that the AFCI is not functioning properly. If this occurs, recheck the operation of the AFCI using the test and reset buttons. The AFCI button test function will demonstrate proper operation.
This caution implies that an AFCI is working properly if the indicator causes it to trip, but the reverse is not necessarily true.  An AFCI that does not trip as a result of an indicator may actually be perfectly fine. The test button on the circuit interrupter can be used to confirm its malfunction in the event that the indicator does not cause it to trip. Manufacturers claim that their AFCI indicators provide a universal method to test AFCIs that are produced by different companies.
 
In summary, AFCI indicators help ensure that AFCIs are properly monitoring the circuits that they serve for dangerous arc faults. These devices create electrical waveforms characteristic of those produced by an actual arc. As their effectiveness has been debated, they should be viewed as a complement to the test button on an AFCI, rather than a substitute.

​Aerogel is a class of porous, solid materials that exhibits an impressive array of extreme properties. Invented in 1931 and used for decades in scientific applications, aerogel is becoming increasingly feasible as a building insulation, largely due to a decrease in the price of the material. 
 
Aerogel is still prohibitively costly for most homeowners, and the few who can afford it probably don’t know what it is. At expensive properties with environmentally friendly features, however, inspectors should be prepared to encounter the material. Also, the prevalence of aerogel is likely to increase in the coming years as it becomes more affordable and widely known. 
 
Physical Properties and Identification
 
Aerogel holds 15 world records for material properties, a few of which are listed below. Aerogel is:

• lightweight. It is, in fact, the lowest-density solid on the planet. Some types are composed of more than 99% air, yet they still function as solids; 
• extremely high in surface area. It can have a surface area up to 3,000 square meters per gram, meaning that a cubic inch of aerogel, if flattened out, could cover an entire football field; and
• strong. It can support up to 4,000 times its own weight. In the picture at right, a 2-gram piece of the material is supporting a 5-pound brick.

The following qualities will also assist with identification. Aerogel:

• appears blue due to Rayleigh scattering, the same phenomenon that colors the sky; 
• feels like Styrofoam® to the touch. Although a slight touch will not leave a mark, pressing more firmly will leave a lasting depression or even produce a catastrophic breakdown in the structure, causing it to shatter like glass; and
• is rigid. Despite its name, it is hard and dry, little resembling the gel from which it was derived.

Performance as an Insulator
Composed almost entirely of gas, which is a poor heat conductor, aerogel can almost nullify the three methods of heat transfer (conduction, convection and radiation). Boasting an R-value of 10 to 30, NASA has used the material to protect astronauts and equipment, such as the Mars Rover, from the extreme cold of space. As compared to conventional insulation material, the R-values of vermiculite, rockwool, fiberglass and cellulose are approximately 2.13, 3.1, 3 and 3.1, respectively. Silica aerogel is especially valuable because silica is also a poor conductor of heat.  A metallic aerogel, on the other hand, would be less useful as an insulator. 

Production
 
Aerogel is derived from gels, which are substances in which solid particles span a liquid medium. The first aerogel was produced from silica gels, although later work involved alumina, chromia, carbon and tin oxide. Through a process called super-critical drying, the liquid component of the gel is removed, leaving behind the hollow, solid framework. The resulting aerogel is a porous, ultra-lightweight lattice composed of more than 90% air. Ordinarily, drying of a gel results in its shrinkage and collapse (think of Jell-O left out for a few days), but super-critical drying is performed under intense heat and pressure that preserve the structure of the gel. 
 Manufacturers offer the material in a variety of forms, such as the granules pictured at right, made by Cabot, which are sometimes used as insulation in skylights. Aspen Aerogel® offers 57-inch wide rolls of the material in 0.2- and 0.4-inch thicknesses, while Thermoblok® comes in 1.5-inch wide strips that are used to cover framing studs and help prevent thermal bridging at a cost of about $1.99 per foot. 

Safety
Aerogel safety is dependent on the safety of the gel from which it was made; it will be carcinogenic, for instance, if the gel from which it was derived had this quality. Fortunately, silica-based aerogel is not known to be dangerous, although it may irritate skin, mucous membranes, eyes, the respiratory tract, and the digestive system. Aerogel is hydroscopic and extremely dry to the touch, which can, in turn, cause it to dry out unprotected skin. Gloves and goggles are recommended for inspectors and contractors who must handle the material.
Aerogel does not seem to be an environmental threat. Aspen Aerogel’s® website states: “Aerogel blankets do not meet any of the characteristics of a U.S. EPA hazardous waste,” and further notes that scrap aerogel may be disposed of in landfills that are approved to accept industrial waste.
 
 
In summary, aerogel is a safe, remarkably effective thermal insulator whose use should become more widespread as it becomes more affordable.

Solar energy offers considerable advantages over conventional energy systems by nullifying flaws in those systems long considered to be unchangeable. Solar power for home energy production has its flaws, too, which are outlined in another article, but they're dwarfed by the advantages listed below. 
 
The following are advantages of solar energy:

• Raw materials are renewable and unlimited. The amount of available solar energy is staggering -- roughly 10,000 times that currently required by humans -- and it’s constantly replaced. A mere 0.02% of incoming sunlight, if captured correctly, would be sufficient to replace every other fuel source currently used. 

Granted, the Earth does need much of this solar energy to drive its weather, so let’s look only at the unused portion of sunlight that is reflected back into space, known as the albedo. Earth’s average albedo is around 30%, meaning that roughly 52 petawatts of energy is reflected by the Earth and lost into space every year. Compare this number with global energy-consumption statistics.  Annually, the energy lost to space is the combined equivalent of 400 hurricanes, 1 million Hoover Dams, Great Britain's energy requirement for 250,000 years, worldwide oil, gas and coal production for 387 years, 75 million cars, and 50 million 747s running perpetually for one year (not to mention 1 million fictional DeLorean time machines!).  

• Solar power is low-emission. Solar panels produce no pollution, although they impose environmental costs through manufacture and construction. These environmental tolls are negligible, however, when compared with the damage inflicted by conventional energy sources:  the burning of fossil fuels releases roughly 21.3 billion metric tons of carbon dioxide into the atmosphere annually.  
• Solar power is suitable for remote areas that are not connected to energy grids. It may come as a surprise to city-dwellers but, according to Home Power Magazine, as of 2006, 180,000 houses in the United States were off-grid, and that figure is likely considerably higher today. California, Colorado, Maine, Oregon, Vermont and Washington have long been refuges for such energy rebels, though people live off the grid in every state. While many of these people shun the grid on principle, owing to politics and environmental concerns, few of the world’s 1.8 billion off-the-gridders have any choice in the matter. Solar energy can drastically improve the quality of life for millions of people who live in the dark, especially in places such as Sub-Saharan Africa, where as many as 90% of the rural population lacks access to electricity. People in these areas must rely on fuel-based lighting, which inflicts significant social and environmental costs, from jeopardized health through contamination of indoor air, to limited overall productivity.   
  
  
• Solar power provides green jobs. Production of solar panels for domestic use is becoming a growing source of employment in research, manufacture, sales and installation. 
  
  
• Solar panels contain no moving parts and thus produce no noise. Wind turbines, by contrast, require noisy gearboxes and blades. 
  
  
• In the long run, solar power is economical. Solar panels and installation involve high initial expenses, but this cost is soon offset by savings on energy bills.  Eventually, they may even produce a profit on their use. 
  
  
• Solar power takes advantage of net metering, which is the practice of crediting homeowners for electricity they produce and return to the power grid. As part of the Energy Policy Act of 2005, public electric utilities are required to make available, upon request, net metering to their customers. This practice offers an advantage for homeowners who use solar panels (or wind turbines or fuel cells) that may, at times, produce more energy than their homes require. If net metering is not an option, excess energy may be stored in batteries. 
  
  
• Solar power can mean government tax credits. U.S. federal subsidies credit up to 30% of system costs, and each state offers its own incentives. California, blessed with abundant sunshine and plagued by high electric rates and an over-taxed grid, was the first state to offer generous renewable-energy incentives for homes and businesses. 
  
  
• Solar power is reliable. Many homeowners favor solar energy because it is virtually immune to potential failings of utility companies, mainly in the form of political or economic turmoil, terrorism, natural disasters, or brownouts due to overuse. The Northeast Blackout of 2003 unplugged 55 million people across two countries, while rolling blackouts are a part of regular life in some South Asian countries, and occasionally in California and Texas. 
  
  
• Solar power conserves foreign energy expenditures. In many countries, a large percentage of earnings is used to pay for imported oil for power generation. The United States alone spends $13 million per hour on oil, much of which comes from Persian Gulf nations. As oil supplies dwindle and prices rise in this politically unstable region, these problems continue to catalyze the expansion of solar power and other alternative-energy systems.

In summary, solar energy offers advantages to conventional fossil fuels and other renewable energy systems.

Craftsman Home Inspections llc is a home inspection company proudly serving the Aurora CO and Denver CO Metro Areas. If you are looking for a Home Inspector in Aurora or Denver, please give us a call at 720-593-0383 or check us out online at CraftsmanColorado.com or simply schedule your home inspection below.

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​by Nick Gromicko

​Adobe is a natural building material made from clay and sand mixed with water and an organic binder, such as sticks, straw or dung. Adobe structures are more common in inhospitable climates and where lumber is scarce.  They're commonly built in low-income communities that lack the resources to construct more complex or conventional designs whose components are more costly. InterNACHI inspectors should be prepared to find adobe buildings in all types of communities -- even wealthy ones -- as green building advocates and experimental builders have become more attracted to adobe construction in recent years.
 
The History of Adobe
 Due to the abundance of its constituents and ease by which it is produced and shaped, adobe construction is truly ancient and universal. Even the word “adobe” has existed for around 4,000 years, with little change in its pronunciation or meaning; it can be traced from the Middle Egyptian word for “mud brick” and was borrowed by Late Egyptian, Demotic, Coptic, Arabic, Old Spanish and, finally, English. Entire cities have been made from the material and many adobe buildings have seen continuous use for thousands of years. Even within the United States, many of the oldest buildings, indigenous and European, were made from adobe. Two such examples are the San Miguel Mission of Santa Fe, New Mexico, thought to be the oldest church in the country, and Pueblo towns and villages that have withstood the winds of the American West since 750 AD. Today, the use of adobe is still widespread across the American Southwest, North Africa, West Africa, western Asia, South America and southern Europe. 
Perhaps not surprisingly, adobe is an ideal building material for the climates in which it is most commonly found, such as deserts and other regions typified by hot days and cool nights. The material’s great thermal mass cannot transfer heat without a relatively long input of sun exposure, keeping the interior cool during the daytime when the sun burns intensely. By the time the sun sets, the thick adobe walls will have absorbed the sun’s heat, which is then slowly released into the living space when the outside temperature is at its lowest. By the time the structure has exhausted its heat reserves, the sun will rise again, starting the cycle anew. 
Adobe provides excellent soundproofing and fire-resistance, which is helpful when a fire must be kept lit during cold nights. It is also easy to produce; according to Sustainable Sources, a green building journal, adobe requires less than 1/150th of the energy required to manufacture a similar amount of Portland cement, and less than five times the energy required to produce ordinary brick.  
Adobe Construction Elements
 
The following materials are commonly found in adobe construction: 

• bricks:  While adobe can simply be piled up and shaped into a structure (as did American Indians before their contact with the Spaniards and their architectural influences), it is generally cast into uniformly sized bricks before they are assembled.  The adobe mixture, by weight, is roughly half sand, one-third clay, and one-sixth straw or some other organic, fibrous material. Modern bricks are 14 inches long, 10 inches wide and 4 inches thick. Water is used to turn the clay and sand into a more fluid, malleable consistency, and the straw helps the bricks shrink more uniformly while they dry. Visible alkali salts or brackish water should be avoided for mixing adobe.  A test brick is sometimes made to ensure the suitability of local soil. To form bricks, the wet adobe mix is poured into molds or pressure-molded using special machinery and then left to cure for weeks. Bricks are sometimes kiln-fired in low temperatures, but their use at the exterior is discouraged in climate zones with daily freeze-thaw cycles;
  
  
• mortar:  Traditionally, mud mortar was used to lay adobe bricks, as the two have the same rates of thermal expansion. Modern adobe bricks may be laid with cement (or some other strong mortar) if the adobe bricks are stabilized during production using certain admixtures, such as asphalt, in order to limit the adobe’s water adsorption. Cement mortar will accelerate the deterioration of natural (or non-stabilized) adobe bricks, however, because the cement is stronger than the adobe;
  
  
• foundations:  The foundations of historic adobe buildings were made from a variety of materials, including seashells, bricks, tile fragments and field stones. In more modern adobe structures, foundations may be large or non-existent.  Adobe structures were rarely constructed over basements or crawlspaces. Modern building codes prohibit the use of adobe as a foundation material due to its low structural strength; 
  
  
• walls:  To compensate for their structural weakness and to support a heavy roof, adobe walls are massive. They may account for 15% to 20% of the weight of the whole house, while frame-house walls account for about 5% of the structure’s weight. The aspect ratio, or the ratio of the height of the wall to its thickness, should not be higher than 10 or the structure will be unstable. For this reason, adobe structures are almost exclusively only one or two stories tall and used for single-family housing;
  
  
• floors:  Floors may be flagstone, tile, fired brick or adobe brick;
  
  
• roofs:  Older adobes of the American Southwest were typically built with flat roofs with parapet walls. Logs and wooden poles were incorporated into the roof for support. Sawn planks and boards are used in newer adobe roofs and for repairs in older adobe. Adobes built over the last hundred years in New Mexico have sheet metal for roofing;
  
  
• bond beams:  On top of the highest layer of brick is the bond beam, which provides a horizontal bearing plate for the roof to distribute the weight more evenly along the wall. They help anchor the roof against wind loads and secure the structure against earthquakes and the gradual effects of gravity. The Universal Building Code (UBC) states: 
  
  The wood tie beam shall be a minimum of 6 inches in thickness, except as provided for walls thicker than 10 inches above; 
  
  
• lintels:  Lintels are used to distribute loads over entrance ways and window openings, as well as for decoration. Concerning lintels in adobe, the UBC states:
  
  Lintels shall be minimum in size, 6 inches by wall thickness. All ends shall have a wall bearing of at least 12 inches. All lintels, wood or concrete, in excess of 9 feet shall have specific approval of the building official; and 
  
  
• footings and stem walls:  The footing and stem wall of adobe houses should be 24 inches and 14 inches, respectively, both of which are somewhat larger than those for frame houses whose difference is due to the greater weight of adobe walls. In colder regions, such as the mountains of New Mexico, adobe footings are dug even deeper to avoid the expansion and contraction caused by freezing cycles. 

Adobe Coatings 
Adobe walls that are not stabilized require exterior coatings to protect against moisture intrusion. Even in stabilized adobe, protective coatings can retard surface deterioration caused by sand, wind and insects. 
 
While inspecting adobe homes, InterNACHI inspectors may encounter the following types of coatings:

• mud plaster:  This was typically used on historic adobe houses because it bonds easily with the brick and exhibits the same expansion under heat. The mud plaster must be smoothed manually, which can be a time-consuming process;
  
  
• whitewash:  Similar to mud plaster, whitewash includes gypsum and acts as a sealant when it’s brushed onto the adobe. It has fallen out of favor in recent years due to its impermanence and high maintenance, as it must be re-applied regularly;
  
  
• lime plaster:  Consisting of lime, sand and water, lime plaster is stronger than mud plaster but it tends to crack easily. Walls are sometimes cut with hatchets to create grooves that encourage the lime plaster to adhere to the adobe. This style became popular during the early 20thcentury; or
  
  
• stucco:  This consists of cement, sand and water and is applied with a trowel over a wire mesh nailed to the adobe surface. This material has enjoyed popularity because it requires little maintenance when applied over fired or stabilized adobe brick and because it can be easily painted. Many New Mexican structures appear to be adobe but they’re actually stucco-clad wood or concrete, as their builders use stucco to convey a historic adobe appearance. 

Adobe Buildings and Moisture Damage 
Adobe structures are extremely vulnerable to the effects of moisture, which are mainly in the forms of rainfall and the local water table. Adobe will lose its structural strength as it becomes saturated, turning into putty and eventually flowing and dripping as a liquid. Rainwater splashes can cause coving, which is the hollowing-out of the wall just above grade level.  The drying process after rainfall can create furrows, cracks, deep fissures and pitting. Weakened walls will bulge, deform and eventually collapse under the roof’s weight. For these reasons, the survival of adobe structures depends on keeping them free from excessive moisture. 
 
The destructive effects of moisture on adobe buildings may be substantially halted by the following remedies:

• Slope the land adjacent to the structure so that rainwater does not pool next to its lower walls. Consider creating drainage channels, French drains or swales to direct rainwater away from the building.
  
  
• Remove trees, plants and other vegetation from the adobe structure’s foundation and walls. Moisture can be collected by their roots beneath, next to or even on the building’s walls. Roots might also be growing into the structure and physically destroying the walls from within. See our article on Tree Dangers for more information about the problems of intrusive roots.
  
  
• Apply hydrophobic coatings to repel water from the walls. In older structures, mud plaster, whitewash or stucco may be used to maintain the historic appearance.
  
  
• Slope the roof. Flat roofs will allow rainwater to pool. Parapet roofs are particularly troublesome, as their high walls will allow rainwater to pool, slowly disintegrating the adobe.
  
  
• Stabilize the bricks near ground level. Natural untreated bricks should not be used within 4 inches of ground level, where moisture intrusion is most likely.

 
Adobe Buildings and Earthquake Dangers
 
Adobe is a heavy yet relatively weak building material, which makes adobe structures particularly vulnerable to earthquakes. The typical mode of collapse is out-of-plane failure of the walls, resulting in the loss of support for the roof. 
 
The scope of this danger can be seen in the devastation caused by the 2003 earthquake in Bam, Iran, where a 6.6 temblor leveled thousands of adobe homes. Along with them fell the 2,500-year-old Bam Citadel, which, at 180,000 square meters, was then the largest adobe structure in the world. 
 
In seismically active Peru, one can further see how not to design earthquake-resistant adobe homes. Traditional construction techniques used there do not call for binding the four walls together, making them vulnerable to even modest seismic shifts in a country that has experienced more than 450 major earthquakes in the last century alone. One Architecture Week reporter commented, “You can see gaps at the corners and between the walls and the roof. That means that when there's an earthquake, the walls just flop outward like cards.  And the roofs, which can weigh up to 11 tons, come crashing down, crushing people to death." 
 
Experimental building techniques in Peru have revealed that strips of electro-welded wire mesh may be used to "sew" the house together along the inside and outside seams of the walls, which are then covered with concrete. Local materials, such as bamboo and sugar cane, have also been used successfully to strengthen houses against earthquakes. These measures do not make the structure indestructible but, rather, allow the occupants extra time to escape before the ceiling comes crashing down. 
 
Building codes related to the structural reinforcement of adobe are more stringent in seismically active regions, and inspectors and adobe homeowners should learn about the earthquake dangers for their region. An engineering analysis should be performed to determine whether and what type of reinforcement may be necessary.  According to the UBC, steel reinforcement, if used in adobe, "should be embedded in a cement-based mortar and grout unless there is a positive interlacing of reinforcement around the earthen material." Misguided attempts to secure adobe walls often cause more harm than good, as steel reinforcement inserted vertically into adobe bricks can cause cracking because it prevents the new adobe from naturally shrinking. Steel will also not bond with adobe as easily as it will with fired brick or concrete.
 Other Inspection Tips
Inspectors may notice that adobe walls are pitted, bulging or cracked, or the roof may be sagging, but the cause of these problems may not be obvious. Yet, historic and modern adobe structures share common deterioration problems, so it pays to understand the basic vulnerabilities inherent in the material. 
 
Consider the following sources of adobe deterioration:

• intrusive vegetation:  Perhaps not surprisingly, adobe tends to attract vegetation and animals that naturally live in soil. Seeds deposited by animals or blown by the wind will germinate there.  Insects, rodents and birds will find adobe walls and foundations very comfortable to nest in. Plant roots will forcefully degrade adobe bricks and retain moisture, undermining the strength of the structure. All plant and animal pests should be removed from the structure unless their removal would cause further damage;
  
  
• sand erosion:  Wind-blown sand is a common source of adobe deterioration in desert climates. This damage is generally found at the top half of the wall and at the corners, where it can be distinguished from coving that is caused by rain splashing on the lower portion of the wall. New adobe mud may be applied where sand has damaged the walls or roof. Trees may also be planted as windbreaks, although they should be planted far enough away from the structure so that their roots do not themselves pose a threat;
  
  
• incompatible materials:  Older adobe structures have periodically been repaired using cement or steel, which may cause the surrounding adobe to crumble. The reason for this is simple: the relatively weaker adobe material is crushed by the newer materials, which expand at different rates due to temperature changes. Watch for the presence of steel doors and wooden lintels. Latex and plastic wall coatings applied to their exterior will not expand with the rest of the structure and will eventually cause portions of the wall to break off;
  
  
• cracks in walls, foundations and roofs:  In adobe, cracks are generally quite visible, but their causes may be difficult to diagnose. Some cracking is normal, such as the short hairline cracks that occur during the curing process as the adobe shrinks and continues to dry out. More extensive cracking, however, usually indicates serious structural problems. The UBC states:
  
  No units shall contain more than three shrinkage cracks, and no shrinkage crack shall exceed 2 inches in length or 1/8-inch in width; and
  
  
• the ground is not compressed or sufficiently tamped before building:  Before assembling an adobe structure, the ground should be compressed because the weight of adobe bricks is significantly greater than a conventional frame house. Uncompressed earth may allow sinking of the structure, eventually resulting in wall cracks, among other problems.

In summary, adobe is an ancient and beautiful building material, and there are ways to prevent it from returning to the earth on which it stands.  InterNACHI inspectors, as well as green homeowners, can help avert costly mistakes and potential disasters by learning some fundamentals about its characteristics.

by Nick Gromicko and Kenton Shepard ​

Adjustable steel columns, also known as screw jacks and beam jacks, are hollow steel posts designed to provide structural support. An attached threaded adjustment mechanism is used to adjust the height of the post. 
 A few facts about adjustable steel columns:

• They are usually found in basements. 
• In some parts of North America, adjustable steel columns are called lally columns, although this term sometimes applies to columns that are concrete-filled and non-adjustable. 
• They can be manufactured as multi-part assembles, sometimes called telescopic steel columns, or as single-piece columns.

The following are potentially defective conditions:

• The post is less than 3 inches in diameter. According to the 2012 International Residential Code (IRC), Section R407.3, columns (including adjustable steel columns)...
  
  "shall not be less than 3-inch diameter standard pipe." 

Poles smaller than 3 inches violate the IRC, although they are not necessarily defective. A 2½-inch post may be adequate to support the load above it, while a 4-inch post can buckle if the load exceeds the structural capacity of the post. Structural engineers -- not inspectors -- decide whether adjustable steel posts are of adequate size. 

• The post is not protected by rust-inhibitive paint. The IRC Section R407.2 states: 

All surfaces (inside and outside) of steel columns shall be given a shop coat of rust-inhibitive paint, except for corrosion-resistant steel and steel treated with coatings to provide corrosion resistance.
Inspectors will not be able to identify paint as rust-inhibitive. In dry climates where rust is not as much of a problem, rust-inhibitive paint may not be necessary. Visible signs of rust constitute a potential defect.

• The post is not straight. According to some sources, the maximum lateral displacement between the top and bottom of the post should not exceed 1 inch. However, tolerable lateral displacement is affected by many factors, such as the height and diameter of the post. The post should also not bend at its mid-point. Bending is an indication that the column cannot bear the weight of the house. 
• The column is not mechanically connected to the floor. An inspector may not be able to confirm whether a connection between the post and the floor exists if this connection has been covered by concrete. 
• The column is not connected to the beam. The post should be mechanically connected to the beam above to provide additional resistance against lateral displacement. 
• More than 3 inches of the screw thread are exposed. 
• There are cracks in upstairs walls. This condition may indicate a failure of the columns.  

 
In summary, InterNACHI inspectors may want to inspect adjustable steel columns for problems, although a structural engineer may be required to confirm serious issues.

Mold in the Home
Health concerns related to the growth of mold in the home have been featured heavily in the news.  Problems ranging from itchy eyes, coughing and sneezing to serious allergic reactions, asthma attacks, and even the possibility of permanent lung damage can all be caused by mold, which can be found growing in the home, given the right conditions. 
All that is needed for mold to grow is 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 and begin growing, they will lead to problems.  Molds produce allergens, irritants and, in some cases, potentially toxic substances called 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 rash (dermatitis).  Allergic reactions to mold are common.  They can be immediate or delayed.  Molds can also trigger asthma attacks in people with asthma who are allergic to mold.  In addition, mold exposure can irritate the eyes, skin, nose, throat and lungs of both mold-allergic and non-allergic people.  
As more is understood about the health issues related to mold growth in interior environments, new methods for mold assessment and remediation are being put into practice.  Mold assessment and mold remediation are techniques used in occupational health.  Mold assessment is the process of identifying the location and extent of the mold hazard in a structure.  Mold remediation is the process of cleanup and/or removal of mold from an indoor environment.  Mold remediation is usually conducted by a company with experience in construction, demolition, cleaning, airborne-particle containment-control, and the use of special equipment to protect workers and building occupants from contaminated or irritating dust and organic debris.  A new method that is gaining traction in this area is abrasive blasting.
Abrasive Blasting
The first step in combating mold growth is not to allow for an environment that is conducive to its growth in the first place.  Controlling moisture and assuring that standing water from leaks or floods is eliminated are the most important places to start.  If mold growth has already begun, the mold must be removed completely, and any affected surfaces must be cleaned or repaired.  Traditional methods for remediation have been slow and tedious, often involving copious amounts of hand-scrubbing and sanding.  Abrasive blasting is a new technique that is proving to be less tedious and time-consuming, while maintaining a high level of effectiveness.
Abrasive blasting is a process for cleaning or finishing objects by using an air-blast or centrifugal wheel that throws abrasive particles against the surface of the work pieces. Sand, dry ice and corncobs are just some of the different types of media used in blasting.  For the purposes of mold remediation, sodium bicarbonate (baking soda) and dry ice are the media commonly used.  
Benefits of Abrasive Blasting
Abrasive (or “media”) blasting provides some distinct advantages over traditional techniques of mold remediation.  In addition to eliminating much of the tedious labor involved in scrubbing and sanding by hand, abrasive blasting is extremely useful for cleaning irregular and hard-to-reach surfaces.  Surfaces that have cross-bracing or bridging can be cleaned more easily, as well as areas such as the bottom of a deck, where nails may be protruding.  Areas that are difficult to access, such as attics and crawlspaces, can also be cleaned more easily with abrasive blasting than by traditional methods.  The time saved is also an advantage, and the typical timeframe for completion of a mold remediation project can often be greatly reduced by utilizing abrasive blasting.  
Soda-Blasting
Soda-blasting is a type of abrasive blasting that utilizes sodium bicarbonate as the medium propelled by compressed air.  One of the earliest and most widely publicized uses of soda-blasting was on the restoration of the Statue of Liberty. In May of 1982, President Ronald Reagan appointed Lee Iacocca to head up a private-sector effort for the project.  Fundraising began for the $87 million restoration under a public-private partnership between the National Park Service and The Statue of Liberty-Ellis Island Foundation, Inc.  After extensive work that included the use of soda-blasting, the restored monument re-opened to the public on July 5, 1986, during Liberty Weekend, which celebrated the statue's  centennial.  
 The baking soda used in soda-blasting is soft but angular, appearing knife-like under a microscope.  The crystals are manufactured in state-of-the-art facilities to ensure that the right size and shape are consistently produced.  Baking soda is water-soluble, with a pH near neutral. Baking-soda abrasive blasting effectively removes mold while minimizing damage to the underlying surface (i.e., wood, PVC, modern wiring, ductwork, etc.).  When using the proper equipment setup (correct nozzles, media regulators, hoses, etc.) and technique (proper air flow, pressure, angle of attack, etc.), the process allows for fast and efficient removal of mold, with a minimum of damage, waste and cleanup.  By using a soda blaster with the correct-size nozzle, the amount of baking soda used is minimized. Minimal baking soda means better visibility while working, and less cleanup afterward.
Dry-Ice Blasting
Dry ice is solidified carbon dioxide that, at -78.5° C and ambient pressure, changes directly into a gas as it absorbs heat.  Dry ice pellets are made by taking liquid carbon dioxide (CO2) from a pressurized storage tank and expanding it at ambient pressure to produce snow.  The snow is then compressed through a die to make hard pellets.  The pellets are readily available from most dry ice suppliers nationwide.  For dry-ice blasting, the standard size used is 1/8-inch, high-density dry ice pellets.
The dry-ice blasting process includes three phases, the first of which is energy transfer.  Energy transfer works when dry ice pellets are propelled out of the blasting gun at supersonic speed and impact the surface. The energy transfer helps to knock mold off the surface being cleaned, with little or no damage.
The freezing effect of the dry ice pellets hitting the mold creates the second phase, which is micro-thermal shock, caused by the dry ice’s temperature of -79º C, between the mold and the contaminated surface.  This phase isn’t as much a factor in the removal of mold as it is for removing resins, oils, waxes, food particles, and other contaminants and debris.  For these types of substances, the thermal shock causes cracking and delaminating of the contaminant, furthering the elimination process.
The final phase is gas pressure, which happens when the dry ice pellets explode on impact.  As the pellets warm, they convert to CO2 gas, generating a volume expansion of 400 to 800 times.  The rapid gas expansion underneath the mold forces it off the surface.  
HEPA Vacuuming
A HEPA vacuum is a vacuum cleaner with a high-efficiency particulate air (or HEPA) filter through which the contaminated air flows.  HEPA filters, as defined by the U.S. Department of Energy’s standard adopted by most American industries, remove at least 99.97% of airborne particles that are as small as 0.3 micrometers (µm) in diameter.  HEPA vacuuming is necessary in conjunction with blasting for complete mold removal.  
While abrasive blasting with either baking soda or dry ice is an effective technique, remediation will not be complete until HEPA filtering or vacuuming has been done.  Abrasive blasting removes mold from contaminated surfaces, but it also causes the mold spores to become airborne again.  The spores can cover the ground and the surfaces that have already been cleaned.  So, the mold spores need to be removed by HEPA filters.  Additionally, while some remediation companies claim that there will be no blasting media to remove after cleaning, especially with the dry-ice method, there will be at least a small amount of visible debris left by the blasting that must be removed before HEPA vacuuming can occur.  HEPA vacuuming removes all invisible contaminants from surfaces and the surrounding air.  When HEPA vacuuming is completed, samples at the previously contaminated areas should be re-tested to ensure that no mold or mold spores remain.
Abrasive blasting using dry ice or baking soda, combined with HEPA-filter vacuuming, is an effective method for mold remediation.  InterNACHI inspectors who offer ancillary mold inspection services should be aware of the benefits and applications of this technique adapted for remediating mold in homes.