Dating Houses
The hardest house to
date is a link home. They appear to be single, but if you do some digging
they’re actually attached.
As home inspectors, we
have some tricks for figuring out the age of a house. In newer subdivisions
we pick up dates from manhole
covers, sidewalks, and
curbs. This will give you an idea of when the subdivision was built. This
obviously doesn’t work in older neighborhoods
Thermal pane windows usually have a
metal strip which separates the two panes of
glass. On that metal strip you will often find
the manufacturer’s name, a CMHC number,
and the date of manufacture. Again, this
information must be used carefully. It will
tell you the age of the window but not
necessarily the age of the house. Check
several windows. If they are all the same,
you have just figured out how old the house
is or the date when all of the windows
were upgraded.
On houses built within the last 20 - 25 years,
you will often find a sticker on the outside of
the electrical panel indicating the possession
date of the house. The Ontario New Home
Warranty Program (in its earlier days know
as HUDAC) placed these stickers on the
electrical panel so that the warranty period
could easily be established.
If you can be sure that the furnace or the
water heater is original, the gas inspection
sticker on either of these appliances is a good
indication of the age of the house.
Porcelain plumbing fixtures usually have a
manufacture date stamped into them. The
easiest place to pick up a date is off a toilet
(no jokes). If you remove the lid from the
tank, the date will often be stamped on the
underside of the lid and also inside the tank
near the water line. The date is usually on
the right hand side of the rear portion of the
tank when you are facing the toilet. The date
inside the tank is more reliable than the date on the lid because sometimes
lids get
broken and replaced. Again, you must look
for other clues to convince yourself that the
toilet is an original one. Otherwise, you have
only established the date when the
bathroom was renovated.
Certain building materials can be clues about
the age of a house. These clues can vary
dramatically by region. For example, in
Toronto, virtually all houses with stone
foundation walls were built before 1930. If you
go to Kingston, Ontario, however, and ask
when they stopped using stone foundation
walls, the response might be "You mean they
stopped using stone foundation walls?".
In Toronto, brick foundation walls were also
popular until about 1935. In other parts of
the province, you will find no brick
foundation walls at all. With the exception of
custom built houses, most houses built with
concrete block foundations are pre 1970.
Most subdivision houses built in the 70’s or
newer have poured concrete foundations.
Most brick houses in Ontario were solid
masonry construction (two wythes of brick)
up until the late 1960’s. Most brick houses
built after 1970 were brick veneer
construction (one wythe of brick with a
wood stud wall behind).
If you stand in an unfinished basement and
look up at the subflooring, you will find that
most houses before 1965 used plank
subflooring. After 1965, most houses had
plywood subflooring, until the early 1980’s,
when waferboard subflooring became
popular (with the builders at least).
Aluminum wiring began to be used
residentially in about 1965, however, it did
not really catch on until about 1970. When
was it banned? It was never banned,
however, it received so much bad press, that
aluminum wiring stopped going into houses
in about 1978. To this day, aluminum wiring
is still used to bring power into the house
from the street!
As you are probably aware, knob and tube
electrical wiring makes insurance companies
very nervous. Knob and tube wiring was
superseded by conventional modern wiring
in the late 1940’s. Even though wiring
looked modern through the 1950’s, it was
not until 1960 that modern wiring contained
a ground wire. Therefore, houses built
before 1960 have two prong outlets as
opposed to modern electrical outlets which
are designed for three prong plugs.
Before 1950, supply plumbing was
galvanized steel. Houses with galvanized
steel supply plumbing also tended to have
cast iron waste plumbing.
In about 1955, waste plumbing was more
likely to be copper than cast iron. In the late
1960’s, the price of copper went through the
roof. Waste plumbing very quickly became
plastic. (It was this jump in the price of
copper that also lead to the use of
aluminum wiring.)
Old houses have plaster on the walls and
ceilings whereas new houses are built with
drywall. When did the change occur? While
there was no magic day when plasterers quit
and drywallers began, most houses built
before 1960 were plaster and most houses
after were drywall.
Dating houses can be helpful for a number
of reasons; for example, the type of furnaces
installed 20-25 years ago have a life
expectancy of 20-25 years. Therefore, most
houses built in the early 1970’s have a new
furnace or will need one shortly. Most
houses built in the early 1980’s were built
with asphalt shingle roofs that lasted up to
15 years. Again, most of these houses either
have a new roof covering or
need one. The good news
about a 1982 house in need
of new shingles is that it
couldn’t possibly contain
Urea Formaldehyde Foam
Insulation. It was banned in
December of 1980!!