Bruce W. Maki,
Frigid Real Estate:
In any area with cold winters there
is a risk of plumbing pipes freezing during cold weather.
I started writing this article to share some
tips on reducing the chances of pipes freezing and reducing the
flood damage if a pipe should actually burst. It seems that
everybody knows somebody who has experienced a burst pipe or a
While writing this article my
drywall-contractor friend Tod dropped by and told me a story about a
house he had just looked at. It was a foreclosure sale and the bank
was trying to sell it through a realtor. The rural house was vacant
and being offered at a good price. When Tod walked in, the house was
stone-cold, but he could hear water dripping. He opened the door to
the basement stairs and was greeted by three feet of water in the
partially-finished basement. Water was spraying from a burst pipe
and he could hear the well pump running.
According to the realtor, the home had been
"winterized" by the previous owners when they moved out. It makes me
wonder what some people think "winterizing a house" actually means.
They did turn down the thermostat, but the propane
tank ran out. They apparently didn't know to turn off the power to
the well pump.
This scenario makes me wonder how many
vacant, foreclosed houses in the northern states are facing a
similar fate. These banks and mortgage companies often don't have
any local staff, so there's nobody to monitor their collateral as it
languishes on the market. The realtor should have known to at
least turn off the circuit breaker to the well pump, but she didn't.
A smart realtor would have also paid somebody to drain the plumbing
supply pipes and pour RV antifreeze in the drain traps. A couple
hours of work is cheap insurance... instead, all the parties
involved just ignored the situation. Or maybe they just didn't know
better. How can someone be in the real estate business and not know
this? It will cost many thousands of dollars to repair the flood
damage to this house, and it will come out of the lender's pocket.
Why Is Freezing Water Such A Problem?
If the temperature inside a house gets below
32 degrees Fahrenheit (0° Celsius) it's likely that the water supply
pipes and the drain traps will freeze. When water freezes it
expands 9 percent, and if there is no room for expansion it's
possible that the pipe will develop a crack. When the ice thaws the pipe will
leak, and in the supply system this leak could occur anywhere.
Fixing a burst pipe can be expensive, but the damage from
uncontrolled water leakage can easily reach into the thousands of
A properly-insulated house built to current
building codes will probably never experience this problem under
normal conditions. What do I mean by normal conditions?
The heating system runs properly, the electricity supply stays on,
and the furnace fuel supply never runs out.
When A Good House Goes
Even a well-insulated
house with plumbing built to current codes can
experience a disastrous water leak from frozen
and burst pipes. But this problem usually only
happens when the heating systems fails during
cold weather and nobody is home to notice. The
classic example is a house left empty while the
owners take a winter vacation. There are several
things that can go wrong:
The furnace can
malfunction and fail to start. Some old
furnaces use a standing pilot (a
small flame that stays lit) which can be
blown out by strong winds sucking air up the
chimney. But there are lots of reasons why
any furnace can malfunction.
The power can go out
for a long period.
The fuel supply gets
shut off. If the fuel is natural gas, there
is a very small chance of the gas supply
being interrupted, as long as the bill gets
paid. However, if the furnace had a standing pilot
and the gas was shut off for just a few
minutes, the pilot will go out and stay out.
The fuel supply runs
out. This is possible if the house is heated
with propane or fuel oil and the homeowners
go away, not realizing that the fuel tank is
approaching empty. What if the owners go
away for a short trip but are unable to
return before the fuel runs out? If their
fuel supplier regularly fills the tank (i.e.
without needing to be called) this problem
is avoided. But some people, for whatever
reasons, aren't on the "automatic fill-up"
plan. Those people need to be aware of the
risk of running out of fuel if they go away
during the winter.
The solution to this
problem is simple: Have someone visit your
house every day or two and make sure
everything is working. This person needs to be
able to reach you if something goes wrong, or be
able to handle the problem. If you have an
existing relationship with a heating system
service company, make sure their phone number is
easy to find (usually these companies will put
their sticker on the furnace).
If it isn't possible to
have someone check on the house, then it's wise
to at least turn off the water supply. If
a pipe bursts, only a few gallons of water will
leak out, not thousands of gallons. The pipe
will still need to be repaired, but that expense
is much less than the damage caused by a gushing
When A Not-So-Good
House Goes Bad:
There are two main
weaknesses in a house that can allow pipes to
freeze in cold weather: Inadequate insulation to
keep all areas warm, and water supply pipes and
fixtures that are not kept inside the insulated
have worked on many houses that have little or
no insulation in the walls. Most of these homes
were older. It seems that houses built after
about 1975 were made with more attention to
energy conservation. In the late 70's and early
80's many states developed building codes that
required a certain amount of insulation... at
least my state (Michigan) did
this. Inadequate insulation is not an easy
problem to fix, but it's important to keep this
in mind when any remodeling is done, especially
changes that involve removing drywall or
exterior siding. I'm a big advocate of
adding insulation to the outside walls
whenever the siding is changed. On many
remodeling projects I have also added a layer of
foam insulation on the inside of the
studs before installing drywall.
point where the plumbing supply pipes are close
to the outside walls is a potential spot for
freeze damage. Since most houses have the
kitchen sink in front of a window, a common
problem is pipes freezing beneath the kitchen
sink. If the wall behind the sink doesn't have
enough insulation, or if the insulation was
installed sloppily leaving gaps (been there...
seen that...) then there is a risk of supply
pipes freezing beneath the sink. The kitchen
cabinets can insulate the contents from the heat
of the house. If there are any air leaks
in the wall or sill area then freezing pipes may
occur when there is a cold wind from a certain
direction. A common recommendation is to leave
open the cabinet doors beneath the sink,
especially at night or when away from home for a
An Example Of Freeze
An example from
my own house illustrates how pipes can
accidentally be put in harm's way.
The front of my
house has a short section where the
floor joists extend beyond the
foundation. There was an outdoor faucet
in this section.
The first time I
turned on this outdoor faucet, water
poured out from beneath the
overhanging area. I removed the
sheathing and fiberglass insulation to
see the exact leak point (red arrow).
The faucet was a
proper "sillcock" where the actual valve
is about 12 inches behind the wall.
Normally this type of faucet won't
freeze because the water is stopped deep
in the house where the temperature is
owner had installed insulation in the
sill area, between the floor joists at
the outside wall. BUT... he insulated
above and below this pipe.
Insulating above the pipe
was a mistake because it kept the pipe
away from the warmth of the house.
This was a classic example of a homeowner
that didn't understand exactly where insulation
should be placed. RULE: The pipes need to
be kept on the warm side of the
insulation. Pipes should never be placed in the
middle of the insulation.
If you closely examine the above picture, you
can see that the leak point was on the
downstream side of the valve seat. This
fixture only leaked when I opened the faucet...
it never leaked when the faucet was off. When an
outdoor faucet develops this type of leak it
usually means that somebody had left a garden
hose (or perhaps some kind of hose shut-off
valve) attached to the faucet in freezing
weather. These freeze-proof faucets can burst if
the little bit of water downstream of the
isn't allowed to drain.
So it's likely that this freeze damage was
not caused by the insulation mistakes. But
the insulation installed on the warm side of the
pipe is still wrong.
from the instruction sheet for a
Mansfield frost-proof sillcock
illustrates my point.
these products always warn users to
never leave a hose attached in freezing
This type of leak can happen to ANY
house if the sillcock is not allowed to
drain because a garden hose was left
The best solution is to build the house
properly. If an older house has insulation problems, this can be
fixed during remodeling. If the work involves removing drywall, then
the wall cavities can be insulated properly. As I mentioned earlier,
foam insulation can be added to the inside face of the studs, or to
the outside walls before siding is replaced, or both. More
insulation can be added to the attic, if there is access. These are
worthwhile improvements because they also reduce the home's heat
loss and therefore reduce the amount of energy needed to heat (and
cool) the home.
But major changes are not in everyone's
budget. A common solution is to apply electric heat tape
around the vulnerable pipes. Some of these products are
thermostatically controlled so they only operate when the
temperature is cold enough to pose a freeze hazard.
The Simplest Solution:
If a house is known to have a problem with
freezing pipes, the simplest solution is to
leave the water running when the temperature
is cold enough for pipes to freeze. Of course,
you must first be aware of this problem, aware
of the weather, and actually be home to run the
The usual advice is to let the faucet run
with a stream of water about the same diameter
as a pencil. That's a pretty serious rate of
flow. If a house has hot and cold water
lines that are vulnerable to freezing, then the
stream needs to be warm water.
This is a waste of energy, but sometimes that's
the only solution available.
This solution works because the water supply
is often quite warm. Here in Northern Michigan
well water stays about 53 degrees all year
around. Even municipal water supplies will stay
quite warm (if the pipes are buried deep enough)
because the ground doesn't often freeze more
than a few feet deep.
But... there are some towns around here with
municipal water service that experience
wintertime freezing of underground water pipes.
The problem is greatest at night because the
temperature is coldest and most people are not
using any water. The branch lines between the
houses and the water main run a serious risk of
freezing, so the town's water department will
issue a notice telling everyone to leave one
cold water faucet running with a pencil-sized
stream of water. One town in my area
does this almost every year in late winter.
Some people have the notion that wrapping
water pipes with insulation will prevent them
from freezing. This is not necessarily true. I
have seen pipes that were insulated and still
managed to freeze. By wrapping pipes with
insulation, there is a risk that the pipes will
be insulated from the warmth of the house.
The main purpose of pipe insulation is to
retain the heat in hot water lines. Insulation
also has the benefit of reducing summertime
condensation (sweating) on cold water lines.
Use pipe insulation with caution. Insulated
pipes that run through a poorly insulated wall
or floor cavity still run the risk of freezing.
If the water is left running, then the pipe
insulation will help retain the warmth of the
water, so a smaller trickle of water can be used
to prevent freezing.
What If Pipes Freeze But Don't Burst?
When the water inside a supply pipe freezes,
it doesn't always damage the pipe. Galvanized steel and some types
of plastic pipe are more rupture-resistant than copper.
If it's a cold winter morning and water
doesn't come out of a faucet, chances are a pipe is frozen
somewhere. Finding the exact frozen area isn't always easy. You
might notice frost on the outside of the pipe...
that's a sure sign of freezing.
Most people just use a hair dryer to warm up
the pipes and wait for water to flow. Of course, you need to leave
that dead faucet open so you can hear the water when it begins to
If the pipes are concealed behind
walls, floors, or ceilings, then it's a much bigger problem. What
can you do?
Wait for the weather to warm up.
Turn up the heat.
Run an electric heater in the space
where the suspected freeze point is located.
Cut a hole in the wall or ceiling and
look around for frosted pipes.
Start a remodeling project sooner rather
None of these options are very good. This
problem seems to occur mostly in old houses that have not had their
insulation updated. Fortunately, most of these older homes have
galvanized steel water supply pipes, which is more capable of
resisting the extreme pressures generated when pipes freeze.
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