One of our trusted vendors in the home inspection field is HouseMaster, and after 40 years of experience inspecting houses and more than 3 million homes inspected, they are a great resource for what is likely to be an issue in a house depending on its age.

Let’s dive into what components of your house are most likely to experience defects in the four big time periods.

Here’s what to look out for!

Here’s a simple table based on the HouseMaster Home Defect Survey that identified what component of a house is likely to experience a defect based on the age of the home.

The table is interesting in itself, but let’s clarify a few things and then interpret what it means for each age category of house.

What’s a defect?

Knowing something might go wrong is helpful, but knowing what that something might be is even more helpful.  Here’s the most typical defects defined for each component of the house.

STRUCTURE – this includes the need for major repairs to the house framing or foundation due to construction deficiencies or damage.

ROOF – defects observed include damaged roofing and flashings requiring repair or replacement. Most roofs will exhibit wear by the time they are 20 years old.

EXTERIOR ELEMENTS – conditions noted in this category include damage or other defects associated with chimneys, siding, decks, porches and stairs.

INTERIOR ELEMENTS – this includes, but is not limited to, defects requiring significant repairs in the living areas of the home affected walls, floors, or ceilings.

WATER PENETRATION – this category represents the homes that exhibited evidence of significant prior or current basement or crawlspace water intrusion conditions.

INSULATION – while not based on an energy audit, these numbers represents the homes where a visual inspection indicated the amount or placement of attic insulation was significantly below current recommended levels.

CENTRAL HEATING SYSTEMS – the typical heating system has a 20 year service life. Defects observed indicated a need for major repair or replacement.

CENTRAL COOLING OR HEAT PUMP SYSTEMS – the typical air conditioning or heat pump system components need major repair or replacement after about 10 years. Defects include equipment and distribution problems.

ELECTRIC SYSTEM – most electric system defects are significant in that safety hazards exist; however, these numbers also represent the times major repairs or upgrades were required due to the aging of components.

PLUMBING SYSTEM – these numbers represent physical defects associated with the piping, plumbing fixtures, or water heater, which typically has about a 10 year service life, as well as water flow or drainage issues.

WOOD DESTROYING INSECT DAMAGE – a home inspection does not include an inspection for wood destroying insects or other pests; however, these numbers represent occurrences that damage associated with wood destroying insects was observed. Warmer climates will have higher incidents of infestation.

Now that we have a handle of what the defects might actually be, let’s review the big picture for your house depending on its age.

The Big Picture if your house was built after 2000

By far the biggest concern (with 38% of homes likely to experience a defect) you will have in a house that built in the last 22 years is the exterior elements such as chimneys, siding, decks, porches and stairs.  This is particularly true in a country like Canada where we face significant seasonal variations in temperature and natural forces affecting our houses.

The next big one is the roof (with 25% of homes likely to experience a defect) which follows the same logic related to exposure to the elements.    While many roof materials promise a life of 25 to 30 years, it does seem common to start to see some issues between 15 to 20 years.  Whether it is flashing that has loosened, or shingles that have curled, it is worth having a roofer take a look at what’s above your heads to make sure your home stays dry.

On the low side of risk (with just 4% of homes likely to experience this defect) is damage to the wood of your home due to insects.  It takes time for termites, carpenter ants and other insects to damage your home, and they need to have access, perhaps due to exterior or roof defects, before that can even begin.

The Big Picture if your house was built between 1980 to 1999

More than half (53%) of homes of this age are likely to experience defects related to exterior elements.  The more time that your house has been exposed to the elements, the more likely some wear and tear and damage is to occur.

The second most likely (38% of homes likely to experience a defect) is actually the electric system, followed closely (at 35% of homes) for the plumbing.  When you think of a home that is between 22 to 42 years of age, there is a significant chance that the original layout and fixtures has changed during that timeframe.  Additional wiring or plumbing can have unintended consequences on those systems and when you add in wear and tear and the aging of components, it is not uncommon to need a plumber or electrician at your house.  When you look at what a newer home (built after 2000) experiences, the likelihood of electrical defect almost doubles and the change of plumbing problem more than doubles.

At the low end of likely problems in a home of this age (with only 11% of houses experiencing defects) is the central cooling or heat pump systems.  While such systems can have lifespans of 20 to 25 years, we can tell you that we’ve helped many clients buy homes where the AC unit is “near the end of it’s expected lifespan” and sold that home 5 to 10 years later with the same AC still chugging away.

A big change from the previous age category (built after 2000) for these homes is the prevalence of wood destroying insect damage, which went from 4% up to 20%.  That’s a significant change from being quite rare (4 out of 100 new homes experiencing the issue) to relatively common (1 in 5 slightly older homes experiencing the issue).  It just becomes more prevalent from this age onward, so keep an eye on the wood in your home as it ages.

The Big Picture if your house was built between 1940 to 1979

The trend with exterior elements being most likely to see a defect continues, with 60% of homes of this age likely to see issues with exterior elements.

The roof and electric system are more or less tied for second place in homes of this age, with the roof have defects in 53% of homes and the electric system in 52% of homes.  The roof makes sense due to the exposure aspect, and the electric system increase is also likely due to the copper shortage in the mid-1960s, which saw aluminum wiring introduced in some homes.  While aluminium is more conductive than copper, it does become defective at higher rates due to the higher rate it contracts and expands.  As well, if a mix of the two is used in a home, it can cause issues that need to be remedied.

The low end (19%) of the likely defect component remains the central cooling or heat pump systems for homes of this age.  It would seem that these systems, which are typically regularly used and ideally regularly maintained, don’t experience defects at the same level as other components of a house.

In terms of significant changes from the previous age range (1980 to 1999 built homes), houses built between 1940 to 1979 see the likelihood of insulation defects more than doubling, going from a 20% likelihood to a 45% likelihood.  Part of that may be due to the difference in recommended levels of insulation from when the homes were built, but also settling and inefficiencies over time.

The Big Picture if your house was built before 1939

With a surprising number of homes in Toronto and older communities in the GTA built before this time, it’s worth knowing the most likely defects in these older homes as well.

The component most likely to see a defect in this age of home remains the exterior elements, now at 65% likelihood.

We have three other components in the 55% to 58% likelihood of defect range, namely the electrical system, the plumbing system and, new to our list of significant likelihood, water penetration.  The aging electrical and plumbing systems running into issues makes sense, particularly as building standards in this time included knob and tube wiring and lead plumbing.  Water penetration becoming an issue is likely related to the exterior element issues over time creating possible areas of penetration.

At the low end of likely defects arising is the central cooling or heat pump systems, which has actually dropped down from 19% in homes built between 1940 to 1979 to just 10% for homes built before 1939.  This is a bit surprising but perhaps due to such homes not having such systems (or certainly not modern versions) and having experienced a major upgrade in relatively recent times.

It is fascinating to see what components of a house are likely to experience defects based on the age.  There are some significant differences in the different eras of home building.  When we look at the average likelihood of all the defects occurring, based on the age of the home this is what we see.

  • 18% of homes built after 2000 will experience some combination of these defects.
  • 29% of homes built between 1980 to 1999 will encounter defects and you’re more likely than not (over 50% do encounter them) to see some exterior elements defects.
  • 39% of homes built between 1940 to 1979 will encounter defects, and you’re more likely than to experience roof, exterior elements and electric system defects.
  • 43% of homes built before 1939 will encounter defects, and if you own a home of that age, you’re more than likely than not to experience issues with exterior elements, water penetration, insulation, electrical systems and plumbing systems.

Now, a word of caution before you refuse to ever buy an older home again.  All of the percentages we’re referencing above are based on what HouseMaster inspectors found when they inspected homes of these age.  It doesn’t mean you’ll encounter these defects in every home of that age, it definitely doesn’t mean you’ll encounter these issues every year or even in your ownership of the home.

If you use this information as a guideline for what you need to consider and ask about depending on the age of a prospective home (or your home), then you will have a much better chance of avoiding an unpleasant surprise!  If you’re interested in buying a home but worried about unexpected costs, then we’d love to work with you and make sure you’re informed and confident in your decision.  Get in touch with us to discuss next steps!