Knowing the age of a home and its components (such as furnaces and windows) can be helpful for many reasons, including assessing structural safety and energy efficiency. Here are a few techniques for guessing the approximate age of a house if you don’t know the date of construction.
Check the foundation.
Stone foundations were used extensively from the 1800s until around 1930. Brick foundation walls were in style from 1910 until the 1930s, while rubble foundations (the first generation of poured concrete) were used during the 1920s and 1930s. Apart from custom-built homes, most houses from the 1940s to mid-1960s have concrete block foundations. Since 1970, house foundations have been built almost exclusively with poured concrete. Each type of foundation has strengths and weaknesses; make sure you are familiar with how these relate to your home.
Most houses built before the mid-1960s had plank subflooring. From the mid-1960s until the early 1980s, plywood was used. After that, wafer board became the material of choice to decrease construction costs.
Check the wires.
Aluminum wiring was used residentially starting in 1965. At that time, the cost of copper was high by comparison, due in part to the Vietnam War effort. Sufficient bad press about aluminum wiring led to a halt in its use in the mid-1970s. In the present day, aluminum wiring has affected the insurability of some homes.
What are the walls made of?
Houses built before 1960 had plaster walls and ceilings; today, new houses are built with drywall.
Check the plumbing.
From 1920 to 1950, water supply plumbing was often made of galvanized steel. Since then, copper has been the number one material, although home builders have recently started using PVC plastic. Waste plumbing was made from cast iron until around 1960, when copper was used for a short time (it was too expensive to keep using). PVC plastic is now the predominant material used.
Rails and ducts offer clues.
Some homes built just after the Second World War have railway rails in the basement used as support beams; Ottawa was once an industrial city and had many old rails and ties. Houses built during the WWII era used tin for ductwork because it was cheaper than using steel, which was needed for munitions. Tin ductwork is typically more shiny than steel.
Look at the bricks.
Some brick homes can be dated by type of brick. For example, the salmon-coloured Glebe brick was manufactured and used on homes built in the 1920s. This particular brick was produced in Ottawa, in the area now occupied by Billings Bridge Shopping Centre.
Investigate other outdoor features for clues.
In newer subdivisions, you can sometimes pick up dates from manhole covers, sidewalks and curbs.
How old is my furnace?
You can check the month, date and year of manufacture; this is usually stamped on the blower fan inside the furnace, by the filter. You just have to make sure this part is the original to the furnace! As for the oil tank, most recent furnaces will have a plaque with the date welded on the tank. This date is required by most insurance companies.
Porcelain plumbing fixtures usually have a date of manufacture stamped inside, or on the rear portion of the tank. Again, is this the original?
Thermal pane windows typically have a metal strip between the two panes that shows their date of manufacture. Are they replacement windows?
Houses built just before the 1980s often have a HUDAC sticker (for Housing and Urban Development Association of Canada) on the electrical panel indicating the original date of construction. n
Steve Clayton, Registered Home Inspector with Capital Home Inspection, has generously contributed to this article.Tel.: 613-233-4515; www.capitalhomeinspection.ca