Are all interior and exterior components of the house examined during a home inspection? The answer is no. A home inspection mainly focuses on the most important and fundamental systems, components, and equipment that make up the house—those that buyers are generally concerned about and that influence their decision-making. These primarily include: roofing and chimney, exterior and garage, foundation/structural system, heating system, cooling system, plumbing system, electrical system, insulation and ventilation, interior and attic, windows/doors, and fireplce.

The Ontario Association of Home Inspectors (OAHI) has a document called the Standards of Practice, which outlines in detail what items should be inspected, what should be described, what is not required to be inspected, and how the report should be written. OAHI requires and monitors its members to follow this standard. Non-members are not subject to such regulation. This standard has been in use for nearly twenty years, continuously revised and improved. It has proven in practice to be a realistic and feasible standard that meets client needs and can be completed within 2 to 3 hours. It is widely accepted by the public, including the real estate industry. Those interested can download it from the OAHI website: www.oahi.com.

The following are not included in this standard (i.e., outside the normal scope of a home inspection): telephone systems, security systems, cable television (these are serviced and maintained by specialized companies), termite infestation, water quality, air quality, and environmental hazard assessments (such as radon gas, toxic gases, electromagnetic fields, etc.). The reasons are:

1. The probability of occurrence is relatively low;
2. These require specialized training and equipment;
3. These cannot be completed within 2-3 hours.

Although these are outside our inspection scope, the OAHI still places importance on educating its members about these topics (e.g., termites, UFFI, asbestos, etc.). Therefore, most home inspectors have some basic knowledge in these areas and will alert clients to perform further inspection when suspicious issues are found. However, clients should understand that these are not within the home inspection scope, and home inspectors are not specialists in those fields. If you have specific concerns, you should proactively hire the appropriate professional or organization for a specialized inspection.

As previously mentioned, the method of home inspection is visual inspection, meaning it is conducted primarily through visual observation and basic operation, with the help of certain tools and equipment. The inspection assesses the current condition of the major systems and components of the home that are readily accessible and operable. That is to say, the home inspector relies mainly on experience and professional training, supplemented by tools, to infer essential conditions through surface appearances. This determines the limitations of the inspection, which mainly include:

1. Hidden issues or those with no visible symptoms are difficult to detect. Home inspectors do not have X-ray vision and current technology does not allow them to see inside walls. In practice, we do not (and cannot) tear open walls, ceilings, or floors; we cannot move all furniture and clutter out of the way; some areas may be sealed off and completely inaccessible—e.g., attic access may be nailed shut. In winter, we may be unable to inspect roofs covered in snow. Also, homeowners may have intentionally concealed some problems in advance; and certain issues only appear seasonally or periodically (e.g., leaks or dampness that occur only during rain or thaw). There may be no visible signs during the inspection, and problems may only surface after someone has lived in the home for some time.
2. Inspection reports only reflect the condition of the house at the time of the inspection. Inspectors cannot predict when a component or system might fail in the future. Just as a car mechanic cannot predict exactly when a car engine might fail, a home inspector can't forecast specific future issues. When we use a moisture meter to check for dampness or leaks, it only indicates the moisture level at that time. If an area had leaked in the past and has since dried, the instrument cannot detect it. If we test a toilet and it flushes well, we still cannot predict when or why it might clog. A basement that has never leaked in the past could leak in the future if exterior drainage is poor and the foundation walls have weak spots.
3. The home inspection is limited by time. For a typical house, the commonly accepted time for an inspection is 2.5 to 3 hours. If we spend half an hour examining a single bathroom, we'll certainly find more issues—but the entire inspection might take two full days. If we were to move all the furniture, clutter, clothes in closets, wall hangings, and floor carpets, we would likely uncover more problems—but just moving and replacing everything might take a full day, and the homeowner likely would not permit it.
4. Home inspectors are generalists, not specialists in every field. They have knowledge across many disciplines, but are not experts in all areas. Some equipment can only be operated by technicians with the proper licenses. If we encounter problems we cannot handle, we will recommend seeking help from appropriate experts. Strictly speaking, to conduct a truly accurate and authoritative assessment of a home, one would need to hire an architect, civil engineer, water specialist, electrical expert, HVAC specialist, and roofing specialist—each to inspect their own area. But this would require a lot of money and time, and in real life it's not feasible (homeowners wouldn't allow it), and usually not necessary.

It is precisely because of the above limitations that most home inspectors will clearly and honestly tell clients: Home inspections cannot identify or predict every problem, and are not a guarantee or insurance of any kind. However, they greatly reduce risk. It is a low-cost, practical, and widely used method of understanding the current condition of a house. The reason I clearly state these limitations is to help everyone form a realistic understanding and reasonable expectations about home inspection. This does not mean that home inspectors are trying to evade responsibility. They should adhere to professional ethics, follow relevant standards and regulations, and work carefully and responsibly—owe the client a duty of care.

This article was originally published in “Real Estate Weekly”, Issue #31, August 12, 2005.