Condensation double pane window is the accumulation of liquid water on relatively cold surfaces.

Almost all air contains water vapor, the gas phase of water composed of tiny water droplets. The molecules in warm airdouble-pane-window are far apart from one another and allow the containment of a relatively large quantity of water vapor. As air cools, its molecules get closer together and squeeze the tiny vapor droplets closer together, as well. A critical temperature, known as the dew point, exists where these water droplets will be forced so close together that they merge into visible liquid in a process called condensation.

Double-pane windows have a layer of gas (usually argon or air) trapped between two panes of glass that acts as insulation to reduce heat loss through the window. Other types of gas used in this space have various effects on heat gain or loss through the window. Some windows also have a thin film installed between panes that separates the space between the panes into two spaces, further reducing heat loss and heat gain through the window. If multiple-pane windows appear misty or foggy, it means that the seal protecting the window assembly has failed.

Silica Desiccant

A desiccant is an absorbent material designed to maintain dryness in the space it protects. In a double-paned window, silica pellets inside the aluminum perimeter strip absorb moisture from any incoming air that enters the space between the panes. If not for the silica desiccant, any moisture in the space between the panes would condense on the glass as the glass cools below the dew point temperature.

Silica gel has an immense surface area, approximately 7,200 square feet per gram, which allows it to absorb large amounts of water vapor. As the sealant protecting this space fails over time, increasing amounts of moisture-containing air will enter the space between the panes, and the silica pellets will eventually become saturated and will no longer be able to prevent condensation from forming. A double-paned window that appears foggy or that has visible condensation has failed and needs to be repaired or replaced.

Why Double-Paned Windows Fail:  Solar (Thermal) Pumping
 
Although double-paned windows appear to be stable, they actually experience a daily cycle of expansion and contraction caused by thermal pumping. Sunlight heats the airspace between the panes and causes the gas there to heat up and expand, pressurizing the space between the panes. At night, the window cools and the space between the panes contracts. This motion acts like the bellows of a forge and is called thermal pumping.

Over time, the constant pressure fluctuations caused by thermal pumping will stress the seal. Eventually, the seal will develop small fractures that will slowly grow in size, allowing increasing amounts of infiltration and exfiltration of air from the space between the panes.

Failure Factors

Windows on the sunny side of a home will experience larger temperature swings, resulting in greater amounts of thermal pumping, seal stress and failure rates.

Vinyl window frames have a higher coefficient of expansion resulting in greater long-term stress on the double-pane assembly, and a higher failure rate. Windows also experience batch failure, which describes production runs of windows, especially vinyl windows, that are defective, meaning that the pane assemblies have been manufactured with seals that have small defects that will cause the window to fail prematurely.

The Nature of Damage

If it’s allowed to continue, window condensation will inevitably lead to irreversible physical window damage. This damage can appear in the following two ways:

  • riverbedding.  Condensed vapor between the glass panes will form droplets that run down the length of the window. Water that descends in this fashion has the tendency to follow narrow paths and carve grooves into the glass surface. These grooves are formed in a process similar to canyon formation.
  • silica haze.  Once the silica gel has been saturated, it will be eroded by passing air currents and accumulate as white “snowflakes” on the window surface. It is believed that if this damage is present, the window must be replaced.

Detecting Failure

Condensation is not always visible. If the failure is recent, a failed window may not be obvious, since condensation doesn’t usually form until the window is heated by direct sunlight. Windows in the shade may show no evidence of failure, so inspectors should disclaim responsibility for discovering failed double-paned windows.

Thermal Imaging as a Detection Tool

Under the right conditions, it’s possible to use an infrared (IR) camera to detect failed windows. IR cameras are designed to record differences in temperature.

Recommendations for Failed Windows

According to industry experts, the glazing assembly can be replaced  approximately 75% of the time.  Occasionally, the sashes must be replaced, and only about 5% of those cases require that the entire window be replaced.

Inspectors should be aware that there are companies that claim to be able to repair misty windows through a process known as “defogging.”

This repair method proceeds in the following order:

  1. A hole is drilled into the window, usually from the outside, and a cleaning solution is sprayed into the air chamber.
  2. The solution and any other moisture are sucked out through a vacuum.
  3. A defogger device is permanently inserted into the hole that will allow the release of moisture during thermal pumping.

Inspectors should know that there is currently a debate as to whether this process is a suitable repair for windows that have failed, or if it merely removes the symptom of this failure. Condensation appears between double-paned windows when the window is compromised, and removal of this water will not fix the seal itself. A window “repaired” in this manner, although absent of condensation, might not provide any additional insulation. This method is still fairly new and opinions about its effectiveness range widely. Regardless, “defogging” certainly allows for cosmetic improvement, which is of some value to homeowners. It may also reduce the potential for damage caused by condensation in the form of mold or rot.  Some skepticism exists about the effectiveness and cost effectiveness of this method of repair.

In summary, condensation in double-paned windows indicates that the glazing assembly has failed and needs repair or replacement. Visible condensation can damage glazing and is the main indication of sealant failure.

Article provided via Nachi.org

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.
Fan Function  
 The fan may be controlled in one of several ways:
  • Most are controlled by a conventional wall switch.
  • A timer switch may be mounted on the wall.
  • A wall-mounted humidistat can be pre-set to turn the fan on and off based on different levels of relative humidity.
Newer fans may be very quiet but work just fine. Older fans may be very noisy or very quiet. If an older fan is quiet, it mayBathroom Ventilation not be working well. Inspectors can test for adequate fan airflow with a chemical smoke pencil or a powder puff bottle, but such tests exceed InterNACHI’s Standards of Practice.
Bathroom ventilation fans should be inspected for dust buildup that can impede air flow. Particles of moisture-laden animal dander and lint are attracted 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.
Defects
The following conditions indicate insufficient bathroom ventilation:
  • moisture stains on walls or ceilings;
  • corrosion of metal;
  • visible mold on walls or ceilings;
  • peeling paint or wallpaper;
  • frost on windows; and
  • high levels of humidity.
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:
  • mid-level in the attic. These are easy to spot;
  • beneath the insulation. You need to remember to look. The duct may terminate beneath the insulation or there may be no duct installed; and
  • under attic vents. The duct must terminate at the home exterior, not just under it.
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.
Mold
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:
  • oxygen;
  • temperatures between approximately 45° F and 85° F;
  • food. This includes a wider variety of materials found in homes; and
  • moisture.
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.
Improper Ventilation
Ventilation ducts must be made from appropriate materials and oriented effectively in order to ensure that stale air isbath-fan-attic-termination properly exhausted.
Ventilation ducts must:
  • terminate outdoors. Ducts should never terminate within the building envelope;
  • contain a screen or louvered (angled) slats at its termination to prevent bird, rodent and insect entry;
  • be as short and straight as possible and avoid turns. Longer ducts allow more time for vapor to condense and also force the exhaust fan to work harder;
  • be insulated, especially in cooler climates. Cold ducts encourage condensation;
  • protrude at least several inches from the roof;
  • be equipped with a roof termination cap that protects the duct from the elements; and
  • be installed according to the manufacturer’s recommendations.
The following tips are helpful, although not required. Ventilation ducts should:
  • be made from inflexible metal, PVC, or other rigid material. Unlike dryer exhaust vents, they should not droop; and
  • have smooth interiors. Ridges will encourage vapor to condense, allowing water to back-flow into the exhaust fan or leak through joints onto vulnerable surfaces.

Above all else, a bathroom ventilation fan should be connected to a duct capable of venting water vapor and odors into the outdoors. Mold growth within the bathroom or attic is a clear indication of improper ventilation that must be corrected in order to avoid structural decay and respiratory health issues.

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 byAluminum Wiring 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.

With barbecue season already here, homeowners should heed the following barbecue safety precautions in order to keep their families and property safe.
  • Propane grills present an enormous fire hazard, as the Consumer Product Safety Commission (CPSC) is aware of more than 500 fires that result annually from their misuse or malfunction. The following precautions are recommended specifically when using propane grills:
    • Store propane tanks outdoors and never near the grill or any other heat source. In addition, never store or transport them in your car’s trunk.
    • Make sure to completely turn off the gas after you have finished, or when you are changing the tank. Even a small gas leak can cause a deadly explosion.
    • Check for damage to a tank before refilling it, and only buy propane from reputable suppliers.
    • Never use a propane barbecue grill on a terrace, balcony or roof, as this is dangerous and illegal.
    • No more than two 20-pound propane tanks are allowed on the property of a one- or two-family home.
    • To inspect for a leak, spray a soapy solution over the connections and watch for bubbles. If you see evidence of a leak, reconnect the components and try again. If bubbles persist, replace the leaking parts before using the grill.
    • Make sure connections are secure before turning on the gas, especially if the grill hasn’t been used in months. The most dangerous time to use a propane grill is at the beginning of the barbeque season.
    • Ignite a propane grill with the lid open, not closed. Propane can accumulate beneath a closed lid and explode.
    • When finished, turn off the gas first, and then the controls. This way, residual gas in the pipe will be used up.
  • Charcoal grills pose a serious poisoning threat due to the venting of carbon monoxide (CO). The CPSC estimates that 20 people die annually from accidentally ingesting CO from charcoal grills.  These grills can also be a potential fire hazard. Follow these precautions when using charcoal grills:
    • Never use a charcoal grill indoors, even if the area is ventilated. CO is colorless and odorless, and you will not know you are in danger until it is too late.
    • Use only barbeque starter fluid to start the grill, and don’t add the fluid to an open flame. It is possible for the flame to follow the fluid’s path back to the container as you’re holding it.
    • Let the fluid soak into the coals for a minute before igniting them to allow explosive vapors to dissipate.
    • Charcoal grills are permitted on terraces and balconies only if there is at least 10 feet of clearance from the building, and a water source immediately nearby, such as a hose (or 4 gallons of water).
    • Be careful not to spill any fluid on yourself, and stand back when igniting the grill. Keep the charcoal lighter fluid container at a safe distance from the grill.
    • When cleaning the grill, dispose of the ashes in a metal container with a tight lid, and add water. Do not remove the ashes until they have fully cooled.
    • Fill the base of the grill with charcoal to a depth of no more than 2 inches.
  • Electric grills are probably safer than propane and charcoal grills, but safety precautions need to be used with them as well. Follow these tips when using electric grills:
    • Do not use lighter fluid or any other combustible materials.
    • When using an extension cord, make sure it is rated for the amperage required by the grill. The cord should be unplugged when not in use, and out of a busy foot path to prevent tripping.
    • As always, follow the manufacturer’s instructions.
Safety Recommendations for General Grill Use
  • Always make sure that the grill is used in a safe place, where kids and pets won’t touch or bump into it. Keep in mind that the grill will still be hot after you finish cooking, and anyone coming into contact with it could be burned.
  • If you use a grill lighter, make sure you don’t leave it lying around where children can reach it. They will quickly learn how to use it.
  • Never leave the grill unattended, as this is generally when accidents happen.
  • Keep a fire extinguisher or garden hose nearby.
  • Ensure that the grill is completely cooled before moving it or placing it back in storage.
  • Ensure that the grill is only used on a flat surface that cannot burn, and well away from any shed, trees or shrubs.
  • Clean out the grease and other debris in the grill periodically. Be sure to look for rust or other signs of deterioration.
  • Don’t wear loose clothing that might catch fire while you’re cooking.
  • Use long-handled barbecue tools and flame-resistant oven mitts.
  • Keep alcoholic beverages away from the grill; they are flammable!
In summary, homeowners should exercise caution when using any kind of grill, as they can harm life and property in numerous ways.

From Barbeque Safety – Int’l Association of Certified Home Inspectors (InterNACHI) http://www.nachi.org/barbeque-safety.htm#ixzz36eQdRW00

Asbestos cement is a composite material consisting of Portland cement reinforced with asbestos fibers.  When manufacturers figured out ways to produce siding made using asbestos cement, it became very popular for a number of years before being banned in the U.S. in the 1970s.  Orange County home inspectors are likely to come across this form of exterior cladding during inspections.  Inspectors and homeowners alike can benefit from knowing more about how the known health risks of asbestos apply to asbestos cement siding, too, as well as some of the common problems and issues associated with the material’s damage and deterioration.

HistoryAsbestos Cement Siding Inspection

Asbestos cement first came into use as an exterior cladding after 1907, when Austrian engineer Ludwid Hatschek came up with a way to shape the material into sheets, allowing it to be manufactured as siding and shingles.  By the 1920s, the National Board of Fire Underwriters recommended that asbestos cement replace wood as siding and roofing material because of its superior fire-resistant properties.  This recommendation from a nationally known insurance board contributed to a boost in sales and, by the 1940s, hundreds of thousands of homes in the U.S. had been constructed using asbestos cement siding.

During the late 1960s and early ‘70s, however, the news media began to report on the health hazards associated with asbestos.  As reports increased, concern grew, so the federal government took action and, in 1973, the EPA banned the use of asbestos in the manufacture of building products.

Health Risks Associated with Asbestos Cement

Asbestos fibers are a proven health hazard if inhaled.  Asbestos dust is a known cause of a type of lung cancer called asbestosis.  Mesothelioma, another deadly form of cancer that attacks internal organs, can also be caused by exposure to asbestos.  However, asbestos cement siding that has been properly installed and is not in a state of decay presents no health risks as long as it remains undisturbed.  This is because the cement binds the asbestos fibers and prevents their release into the air, under normal use and maintenance.

The EPA deems asbestos to be hazardous when it is in a friable state, meaning that it can be crumbled, crushed or pulverized by hand pressure.  Crushed asbestos in a powdery form can allow its particles to become airborne and inhaled, causing potential health problems.  Asbestos cement products that are not in a friable state are not considered hazardous.  The only potential danger is when the cement is disturbed in a way that causes the asbestos fibers to become airborne.

If mechanical activities performed on the siding, such as chipping, sawing, grinding or sanding, allow particles to become airborne, then the cement is considered in a friable state and, consequently, hazardous.  Deterioration can also lead to particles becoming airborne and potentially dangerous.

AdvantagesAsbestos Cement Siding Inspection

  • Asbestos cement siding is highly fire-resistant and will not burn or melt the way vinyl and wood siding will.
  • It resists termite damage.
  • It resists rotting.
  • It has been manufactured with textures intended to simulate the look of other cladding materials, such as wood grain.
  • It is fairly easy to clean and maintain.
  • Unlike more porous siding materials, such as wood clapboard, asbestos cement siding will not quickly soak up paint, which allows it to be painted more easily.

Disadvantages

  • Asbestos cement siding is very brittle and can be easily chipped, cracked or broken.  Asbestos Cement Siding Inspection
  • The use of a pressure washer for maintenance can crack the siding and lead to moisture intrusion, if the pressure setting is high enough.
  • Asbestos cement can be dangerous if pulverized by sawing, sanding, breaking, etc.
  • It is difficult to find replacement siding for repairs.
  • This product cannot be refurbished, unlike other forms of siding.  Wood clapboard, for example, can be sanded and re-painted, and cedar shake siding can be sand-blasted and re-stained.  Either of these methods can restore wood close to its original state.  But this is not possible with asbestos cement siding.
  • It is no longer considered aesthetically desirable.

Maintenance

Damage and deterioration can lead to structural and health issues, so proper maintenance of asbestos cement building materials is a primary concern.  Keeping the siding clean and performing any minor repairs as soon as they become necessary are both important.

Asbestos cement siding is fairly brittle and has little resistance to cracking, chipping and damage from impact, which can cause asbestos particles to become airborne.  Damage to the siding can also lead to other damage related to moisture intrusion.  Damaged areas that cannot be fixed can be replaced with non-asbestos fiber cement by a professional.  Specific fiber cement materials have been manufactured for repairs that are intended to mimic the look of asbestos cement siding.

Landscaping features, such as a row of shrubs, can be incorporated around the home to help protect the siding from impact damage.

Homeowner Tips

Here are some common problems associated with asbestos cement siding that homeowners are likely to encounter:

  • Chipping and cracking often occur with this brittle material.
  • Fasteners used to hold the siding in place may deteriorate at a faster rate than the siding.
  • Discoloration and staining may occur from corrosion or runoff from an adjacent material.  The discoloration may be normal, but it could also indicate a chemical reaction that has decreased the durability of the material.
  • Like many other cement products, efflorescence may appear on asbestos cement siding.  This crystalline growth can indicate that water is passing through the material, promoting deterioration of the cement.
  • Biological growth, such as moss and algae, can occur if conditions are favorable.  This growth may stimulate surface deterioration and staining.
Because it was such a popular cladding material for many years, inspectors are likely to encounter asbestos cement siding when inspecting exteriors.  Knowing some of the health risks associated with this material can be useful when answering clients’ questions about asbestos, although any specific concerns should be deferred to the appropriate healthcare professional.  Homeowners will want to hire an InterNACHI inspector for the periodic inspection of this type of cladding as part of their annual or regular home maintenance

From Asbestos Cement Siding Inspection – InterNACHI http://www.nachi.org/asbestos-cement-siding-inspection.htm#ixzz36Q2777Z3