Frozen Water Pipes and How to Test Your House for Freezing Pipes
Hey this is Jon with Two Moose Home Inspections, let’s talk about your frozen pipes, welcome to inspector insights.
During the winter it is very possible that the water pipes in your home could freeze resulting in severe and costly damage to your home. During this video we will be discussing the natural events, construction practices, and the things we do as homeowners that lead to frozen pipes. We will then discuss some different ways of reducing your risk and how to check if your pipes are at risk of freezing.
Uncontrollable Events
Cold weather is the first prerequisite for frozen pipes, but most houses can handle the cold without any issues, so what does it take to be at risk? It is important to remember that the difference between liquid water and frozen water is just 1˚, so houses that are already on the cusp of having frozen pipes during a normal winter season a susceptible to changing exterior temperatures, changing interior temperatures, opening or closing doors inside the house, and how frequently the plumbing is being used. If any of these variables change it is possible that the pipes could freeze. During an extreme cold weather event it is imperative that steps are taken to prevent the pipes from freezing.
If there is a power outage, an interruption of natural gas, an empty propane tank, or an unexpected failure of the furnace or boiler, the pipes in your house have a limited amount of time to be saved before they freeze.
Construction Practices
Not all houses are created equal. The placement of the pipes in the house and how well the house was insulated has a massive impact on the likelihood of freezing. Standard construction practices don’t always turn out well in high alpine environments. Exterior walls have historically been made with 2”x4” wooden studs which provide a limited amount of space in the wall for insulation and unfortunately when that space is taken up by plumbing pipes, there is no effective way to properly insulate that space. That is why homes built in cold climates shouldn’t have pipes installed in the exterior wall. To keep the pipes installed on the exterior of the home from freezing some homeowners have learned to keep the cabinets under the bathroom or kitchen sink open during cold weather events. This is done to allow the warm conditioned air in the home to escape into the cabinet, through the drywall, past the pipes located in the poorly insulated exterior wall, and out the house. Hopefully as your expensive heat escapes past the pipes enough of that heat can be absorbed by the pipes before it escapes to prevent the pipes from freezing. If the cabinets are shut the warm air from the house may not be able to heat the pipes well enough and the pipes might freeze.
Some houses have plumbing in the crawlspace, but the crawlspace is not a conditioned space which means that it isn’t heated or cooled which can lead to frozen pipes. Some crawlspaces are vented which means the air in the crawlspace is being exchanged for the freezing cold air outside which will definitely result in frozen pipes. Your first thought might be to close the crawlspace vents to prevent the cold air from entering the crawlspace, but two health hazards can occur when you do that.
First reducing the crawlspace ventilation can result in an increase of radon inside the house that might be above the EPA action level of 4.0 pCi/L which means that your family will be at risk of developing lung cancer from radon. The second issue can also cause respiratory issues because the moisture that might be present in the crawlspace is no longer being vented to the exterior which could result in mold growth which can be harmful to the occupants of the home.
Similarly, attics spaces are also not conditioned spaces but yet plumbing is run through the ceilings or attics of homes. Clearly since attic spaces are vented and designed to create a continuous exchange of air from the exterior to the interior of the attic, the risk for frozen pipes can exist. However, this normally isn’t an issue when the inside temperature of the house is set to a comfortable level because the heat will rise and escape out of the roof of the house which we talked about in our ice dam videos and blog post.
Homeowner Actions
One of the most important aspects of preventing your pipes from freezing is to keep your house warm. If your house is kept at a reasonable temperature, then the pipes in your home should be capable of staying warm enough not to freeze. When a home is not in use such as a second home, rental property, or just waiting to be sold, the owners might try to save a little bit of money by lowering the temperature in the house to reduce the heating bill, but we have seen frozen pipes in houses that have had their temperature set at 60˚F. Most Empty homes that we inspect are set to the lowest heating settings which is about 55˚F. When the house is set 15˚ lower than normal that is more than enough of a drop in temperature to cause the pipes to freeze. Remember it only takes a drop of 1˚ to freeze.
Another consideration for second homes, rentals and those waiting to be sold is the lack of water consumption. Some homes have sections of pipe that can be at risk of freezing, but when water is used throughout the day that section of pipe may not have a chance to freeze. Lets assume that a section of pipe might take 48 hours to freeze during the winter. If a home is used every day the water in the pipe is replaced by an above freezing supply of water and the 48-hour countdown restarts. If a homeowner is away for an extended period of time the pipe could freeze solid.
Frozen Pipes and Ruptures
This sounds rather doom and gloom… Is it always game over when a pipe freezes? Well… It Depends. If the pipe or its fittings don’t rupture, then the worst thing that will happen is that you won’t have water until the frozen blockage melts or can be bypassed. But, depending on how quickly the pipe freezes, what section of the pipe freezes, and how much of the pipe freezes the pipe may or may not be damaged.
As water freezes it expands which can cause a pipe to rupture. If a pipe freezes quickly the water will be frozen in place which might cause a localized rupture. If the pipe freezes more slowly the water may have an ability to expand along the length of the pipe which would allow the pipe to freeze without rupturing. Some pipes like PEX can expand slightly so the likelihood of a rupture is reduced. PEX is the most rupture resistant pipe material followed by copper and then CPVC far behind the pack. If you have Galvanized pipe or polybutylene then you have more issues to worry about than just freezing. If the section of pipe that freezes is located between fittings such as 90˚ elbows or tee junctions the fittings could be forced off the pipe or the rupture could be localized in the joint. If only a small amount of the pipe freezes the expansion tank on the system may be able to absorb the extra pressure created by the ice blockage.
Thaw and Water Damage
The real issue with frozen pipes is not fully realized until the pipe thaws. When a pipe thaws the water will begin leaking out of any compromised section of the pipe. When this happens not only will building materials and personal items be at risk of water damage, but once the water is stopped the risk of mold then becomes the next greatest concern. Sometimes the source of a leak is very difficult to find because water doesn’t always present itself near the source of the leak. The water may not become visible until there is a natural break in construction materials such as 8 feet away from the leak at a drywall seam. What this means is that a large section of ceiling, floor, or wall may need to be removed to find the leak which can make the repair extremely expensive. Even if there is no immediate leak caused by the pipes freezing, it is still very possible that the pipe’s strength is compromised which may result in a leak days, months, or even years from the initial pipe freeze.
Insulation
Insulation can be applied directly to water pipes to reduce the risk of freezing. This type of insulation is most effectively used to prevent heat loss from hot water pipes, but people also apply insulation to pipes trying to prevent the pipes from freezing. Insulation only slows the rate of heat loss as it does not provide heat. If above freezing water is not passed through the pipe, then the pipe will freeze regardless of how much insulation is added.
Running Water
If you are concerned that your pipes might freeze during an extreme cold weather event you can turn on your faucets on to a slow trickle which will help to reduce pressure inside the pipes, supply the pipes with an above freezing supply of water, and if the pipes do freeze it will allow the pipes to freeze in a uniform manner which will reduce the risk of rupturing. It is still possible that the heat loss in one section of pipe is greater than the heat gain from the above freezing supply of moving water, which would then lead to localized blockages that result in ruptures.
Heat Tape
If there are sections of exposed pipe that are at risk of freezing such as a water supply pipe in a non-conditioned vented crawlspace then heat tape might be a good option to keep the pipe above freezing temperature. Continuous voltage heat tape may be a fire risk because it can create hotspots when the wire is overlapped, but variable voltage heat tape will modify resistance along the length of the wire to prevent hotspots and reduce electrical bills. If heat tape is improperly installed it is possible to create unintended fire and electrical shock hazards, and if the electricity goes out there is nothing that heat tape can do to help protect your pipes.
Water Circ Pumps
Normally the hot water pipe runs parallel to the cold water pipes and this can help you keep the cold water line above freezing through parasitic heat loss. Some of the heat being radiated off the non-insulated hot water pipe will be absorbed by the cold water pipe. A water circulation pump can be added to keep the water in the system moving and heated. If your house has a water circulation system the pipes may be at a lower risk of freezing.
Heating the House
Increasing the temperature inside the house can help to reduce the risk of freezing pipes. It may be a good idea to increase the temperature of your house by a few degrees during an extreme cold weather event. This will help make sure that the heat of the house can penetrate into the walls far enough to warm the pipes. If you are concerned about plumbing located on the exterior wall you can open the cabinets under the bathroom and kitchen sinks to help the warm air in the house reach the pipes.
If your pipes are located in the crawlspace, you can install insulation to reduce the heat draw caused by the cold foundation and ground. Insulation will only help in the crawlspace if the crawlspace is not vented. If your crawlspace is sealed and insulation you can install a small electric heater in the crawlspace to help keep the temperature of the crawlspace above freezing, but this solution will not only increase your electrical bill, but it will also be completely ineffective if your electricity goes out. Remember, If the crawlspace is vented and you close the vents that can cause some serious issues such from an increase in both Radon and Mold.
Alarms
If you have done all that you can to prevent freezing pipes and you’re leaving your house for a period of time in the winter, you can install leak alarms and temperature alarms to send an alert to your cell phone if water or freezing temperatures are detected. Unfortunately, this won’t help you shut off the water or fix the heating issue, but it allows you to be proactive for a relatively low cost. Unfortunately, if the power goes out these options may not function unless they are installed with a battery backup system.
Automatic Valves
Water usage and leak detection valves learn how water is used in your house and shut off the water if they sense a leak or unusual behavior. Battery backups can be installed to ensure that the system works during power outages and this system can prevent tens of thousands of dollars of damage when you are away from the house. These types of automatic valves can be worth their weight in gold not just for freezing pipes, but also ruptured supply lines for refrigerators, ice machines, laundry machines, or dishwashers.
Test Your System
If you want to get an idea about the amount of risk your pipes are facing each winter you can perform this simple analysis. First record the inside temperature of your house and outside temperature, then run the cold water and place a thermometer in the water stream. Keep track of the changes in temperature and record the lowest temperature. If the water pipes are on the exterior of the house the thermometer may have the lowest temperature reading shortly after you turn on the faucet. If the pipe travels through a cold attic or crawlspace the lowest temperature water may take several seconds to reach the thermometer. After a few minutes the temperature of the water should drop even lower and stay consistent which would be representative of temperature of the water supply. You can then use this information to help you make assumptions about your risk of freezing pipes. The best time to run this test is early in the morning after a cold night before anyone has had a chance to run the water. Next you will repeat this procedure on a different day. It doesn’t matter if the outside temperature is warmer or colder as long as the difference in temperature outside is significant such as 20˚ or more. Ideally your inside temperature would be constant which would leave you with two outside temperatures and two water temperatures. This can help you understand what temperature your pipes might be at risk of freezing.
You can apply this information by using some graph paper and plotting your data on the page. If my first measurement had an outside temperature of 50˚ and a water temperature of 60˚ before the water supply stabilized at 40˚ I would place a dot at that intersection. If my second measurement had an outside temperature of 30˚ and a water temperature of 45˚ before the water supply stabilized at 40˚ then I would place a dot at that intersection. When I draw a line between those two points, I can extrapolate that my pipes might be at risk of freezing when it is about 14˚ outside. I can repeat these steps as many times as I want to ensure that I have accurate data to base my decisions on. Now I am going to plot a water supply that isn’t at risk of freezing. If my initial measurement remained the same but my second measurement had an outside temperature of 10˚ and a water temperature of 55˚ you can see that when I draw a line between the to points there is no reasonable risk of freezing as long as the interior house temperature remains constant.
Hopefully you learned a little about freezing water pipes and some of the things you can do to prevent them from happening to you.
If you have any questions or if you would like to schedule a home inspection, please visit Two Moose Home Inspections .com, have a wonderful day!