Older Homes, Older Systems: Understanding the Material Risks

Knowing a home's original age is only a starting point to anticipating potential concerns. Not all older homes are going to have issues, but the probability of identifying deficiencies or hazards are much greater. A prudent first step to reducing your buying and ownership risks is retaining the services of a licensed, experienced, and knowledgeable Home Inspector.

Although building science, practices, and material technologies have been improved overtime, older building materials and techniques still remain in service with older homes. Older systems either reach the end of their serviceable-life, require improvement, or removal and replacement from future service based on known issues or risks. For example, design flaws and non-performance issue ('leaky condos' in BC), and health and safety risks (increased probability of electrical fires due to aluminum branch wiring and soil contamination from underground oil tanks). Older homes, especially those that have not been sold for decades, or not renovated/ improved at some point in the past, are commonly going to have defects/ deficiencies that a home buyer needs to know about prior to purchase.

Whether future plans for your older home includes no short-term improvements or extensive renovations, you need to ask the right questions to understand known issues. Certain issues can expose you to a whole new level of added requirements, such as:

  • Additional material evaluation/ sampling/ testing by qualified subject matter experts
  • Special permits for removal/ remediation of legacy materials
  • Difficulties finding insurance coverage or paying higher insurance premiums due to specific risks
  • Overall hidden costs that you never budgeted for, either affecting your ability to care for the property, reducing the future value of the property and/ or reduced buyer interest of your property at resale

Some of the more notable issues of older homes are as follows.

Asbestos insulating material

A commonly used material for attic/ wall insulation was vermiculite. It was generally used in homes between the 1930s and 1950s, however there are always exceptions. Although other products existed, vermiculite ore produced by the Libby Mine, Montana (sold as Zonolite® Attic Insulation) was distributed extensively in Canada. Not all vermiculite products contain asbestos fibers.

If this type of insulation is sealed behind walls, isolated in an attic, or otherwise kept from the interior environment, then your risk of exposure is suggested to be reduced. Generally though, if the asbestos material can be accessed, and disturbed to the point of being "friable" (can it be crushed, or reduced to powder by disturbance or pressure), then the fibers/products are indicated to increase health risks. Disturbance of the materials during maintenance, renovation, or demolition is a perfect example.

Given that construction trade workers are generally exposed to higher levels of "friable" materials while performing renovation activities, Work Safe BC has regulations in place that need to be understood before commencing renovation work. Any additional requirements for the work to be performed will add to your overall costs. For additional information search online for “Hazardous Products Act (Canada)” or “worksafebc asbestos guidelines."

Insulation is not the only source of asbestos fibers found in homes.

Buried oil tanks

Although a regionally specific practice, it was common to bury fuel-oil tanks that serviced forced-air heating systems. Around the late 1950s regulations changed, and tanks were then installed into basements and the exterior of homes. Buried tanks were generally abandoned when new above ground tanks were installed, or after homeowners moved to newer fuel sources. However, buried oil tanks are still being found at the front, rear, and side-yards of homes constructed later into the early 1960s.

Buried tanks pose a safety hazard and a financial risk to buyers, current homeowners, and their neighbors, as the remaining contents of the tanks may have leaked into surrounding soil - assuming the tank was abandoned with oil in the tank, and the tank has been compromised by rust. Disposal guidelines vary and may call for removal of the tank or filling it with sand or gravel - regulations and requirements are becoming more stringent. Soil testing may be required to establish whether an abandoned tank has leaked oil underground and contaminated the surrounding soil. Costs for some site remediation have been in the five-figure range and have triggered lawsuits as a result.

If you have any concerns about the house contact the local Fire Department for past permits issued for historical installations, and hire a company to perform a comprehensive site-scan. Site-scans are performed with a wide variety of technologies, and know that there is always a risk of multiple buried tanks on the property.

Legacy electrical practices

Older electrical wiring and components generally pose a higher risk for both fire and safety issues. Some common electrical installation practices with known issues:

    • Knob-and-tube (K&T) wiring. 
      This was an early standardized approach of electrically wiring buildings from around the late 1800s to the 1940s. While regulations do not require its removal, unsafe alterations, in-service age, overheating, and lack of a ground wire are some of the primary concerns with K&T wiring. If there are any identified upgrades to the original K&T wiring, further evaluation by a qualified Electrician may be required.
    • Aluminum branch wiring.
      Between approximately mid-1960 to 1973, single-strand aluminum wiring was often used instead of copper branch wiring. The installation practice at the time was due to the rising price of copper. If properly maintained, aluminum wiring can continue to perform as intended. However, due to the inherent characteristics of aluminum (thermal expansion/ contraction, and rust), the branch wiring can become defective over time. The most common concerns are termination points where the aluminum wiring is connected to various devices; a wall plug for example. There are modification options that can make the branch wiring safer, so if aluminum branch wiring is identified (installed as original, or introduced at the time of a renovation), it should be evaluated by a qualified electrician.

An older home often means common defects and outdated components, yet without the proper onsite condition evaluation by a qualified home inspector, you may not fully know or understand the potential risks when buying your next house. As part of your home-buying strategy, perform your research early since scheduling of real estate transactions are time sensitive, and you want to know you have the right people working for you.


Brad O'Connor CMHI, BA (Econ) is the President of Coastal Inspection Services Inc. He is a licensed Home Inspector with Consumer Protection BC, CanNACHI CMHI - Certified Master Home Inspector; InterNACHI, Infrared, and AHIT Certified ensuring his clients receive the most complete, professional home inspection in the market today.

With over 16 years of combined residential construction and home inspection experience, he reduces his client's overall home buying risk by presenting an unbiased opinion on the condition of a homes primary systems, and related components - all clients are able to make sound, buying decisions.

Brad is available at:


1-855-TO-INSPECT (864-6773)