Will PEX Pipes Freeze in a Crawl Space? Here Are Ways to Prevent Them from Freezing

Pex pipe freezing

Freezing temperatures can become a hassle for homeowners who experience freezing weather. Plumbing becomes a problem that leads to burst pipes and increases repair costs.

Especially in crawl spaces, the temperatures can get too low for pipes to work.

All kinds of pipes are bound to become a nuisance, including PEX pipes.

Some homeowners believe that PEX pipe freezing is impossible because they are resilient to cold temperatures.

However, PEX pipes are not immune to freezing temperatures.

Bursting or cracking is a common plumbing problem that can happen to any pipe, even PEX.

But there are ways to prevent that from happening.

This article outlines effective methods for preventing PEX pipes from freezing.

Why Are PEX Pipes Preferred?

Some areas have long winters, while others have sudden drops in temperature that could be bad for plumbing.

Given the risk of freezing and bursting pipes, it becomes difficult for homeowners to decide which piping is the right one for their house.

They also have to consider the correct type for their crawl spaces, so PEX pipe freezing becomes impossible.

When it turns into a headache, PEX pipes are the better option because of the following reasons:

Freeze Resistance

PEX pipe freezing is rare compared to rigid pipes.

PEX is cross-linked polyethylene that is flexible and freeze resistant and can endure increased pressure.

So, winters are better for PEX pipes, even when the water freezes.

If you get PEX pipes installed in your home, you’ll notice that they expand when water freezes and return to their original shape when thawed.

Therefore, PEX pipes can survive in crawl spaces, too, if the cold temperatures are not extreme.

Corrosion Resistance

Water high in pH level is acidic, which easily corrodes metal pipes.

It can take a few months or years for the corrosion to destroy the metal pipes in your plumbing.

But PEX can save you from corrosion because it does not get affected by acidic water.

Some suburbs or cities have acidic water running through the plumbing systems, which can have an undesirable impact on the piping if it’s not PEX.

In case you live in a place with acidic water, we would suggest PEX piping for plumbing to avoid any harm.


If you are worried about the PEX pipe freezing, you should know that their flexibility makes it easier for the pipes to expand and contract in cold weather conditions.

In fact, flexibility is one of the main reasons people opt to install PEX pipes in their homes.

These pipes are made of plastic material, making it easier to run them around the corners of the house without any connectors.

You can also snake the pipes behind walls and save on demolition expenses that are usually required for rigid copper pipes.

Cost Saving

When you are renovating your home, you look for materials and tools that are cost-effective.

However, plumbing is something you would not want to compromise the quality for cost reduction.

Still, copper pipes have become too costly for most homeowners to buy and install.

That’s why they look for reliable options that do not hit their budget.

And that’s where PEX pipes come in! Regardless of the weather condition, PEX works better than copper pipes in most cases and saves you money.

DIY Benefit

A great benefit of having PEX pipes in the house is installing or fixing them yourself.

For copper pipes, you have to know to solder before replacing or repairing them. However, PEX pipes do not have any condition like that.

For example, if you have PEX pipe freezing in your crawl space and you need to get it repaired.

You can simply follow the basic PEX pipe thawing procedure and get the piping back to normal.

If this were a situation with copper pipes, you’d have to call a professional to do it.

Are PEX Pipes Really Freeze-Proof?

In the previous section, we talked about the benefit of using PEX pipes in the winter season.

But we also said that PEX is freeze resistance, not FREEZE PROOF!

Although PEX pipes can tolerate cold temperatures better than any other pipes that you have encountered, it does not mean PEX won’t freeze or break.

PEX pipe freezing is normal in places with extremely harsh weather conditions.

It could be an outside weather factor like a sudden drop in the temperature or another reason like a frozen crawl space.

However, it’s hard to determine what exact temperature causes the freezing in PEX pipes.

As the material is plastic, the pipes do not freeze themselves, but the water inside can easily freeze when the surrounding area reaches the freezing point.

For example, if the temperature outside the house is somewhere around 32 degrees, it’s not the same for underground pipes.

The outside temperature has to be a lot lower for the crawl spaces to have a freezing point temperature and cause PEX pipe freezing.

Pex pipes freeze in crawl spaces

People have been led to believe that PEX pipes are freeze-proof and can be installed in a house to endure harsh weather conditions.

In fact, some plumbers have used PEX, believing that it actually can survive extremely harsh conditions.

However, it’s all part of the myth surrounding the best plumbing for cold weather.

To some extent, PEX is better than other pipes and can survive the winter if the temperature is moderate for a cold season.

If the outside temperature is below freezing point, the PEX pipes freeze in crawl spaces, and sometimes, they even break.

It usually occurs when the PEX has been in use for a long time.

The expansion ability decreases with time, and as the pipe ages, it is more likely to act as a rigid pipe and burst upon reaching the freezing point.

Another factor that degrades PEX’s expansion is the use of chlorine in the water.

Is Frozen Water the Cause of PEX Pipe Expansion?

The short answer is NO. Although one may think that frozen water causes the PEX pipe to freeze, frozen water cannot expand the pipe and damage it.

When the surrounding temperature is below the freezing point, first the water freezes, and then ice forms on the inner surface of the PEX pipe.

As the temperature does not increase, the ice keeps growing inwards, given the harsh climate conditions.

It eventually becomes a plug that pushes down the length of the pipe until it has no more space to move.

The plug pushes against the frozen water and expands the pipe to accommodate the built-up pressure.

PEX Pipe Freezing in Crawl Spaces

We understand now that the surrounding temperature can cause an expansion in the PEX piping with frozen water and ice forming on the inner surface.

But is it possible to prevent PEX pipes freeze in crawl spaces?

Yes, it’s possible to avoid freezing by implementing a few techniques during the winter season.

PEX pipes can run along the outside wall of the house or the insides of the crawl space.

When the areas surrounding the pipes are not heated or insulated, they can lead to freezing if the outside temperature is cold enough. If you can insulate the water supply lines and PVC drain traps, you will decrease the chances of PEX pipe freezing or cracking.

You will have to insulate both hot and cold water lines to stop the freezing.

When you insulate the hot water line, it delivers the water to the pipe fixtures faster and slows down the cooling of pipes.

Similarly, for cold water lines, you can insulate the pipes that will form condensation in the hot weather and contribute to crawl spaces remaining damp.

PEX piping can be a highly functional plumbing system regardless of the weather conditions.

You will not have to worry about yearly pipe bursts if you use methods that prevent the PEX pipes freeze in crawl spaces.

Insulation of PEX Pipes

PEX pipe insulation can decrease the potential risks of failure due to moisture condensation.

It can promote energy efficiency and save money by providing a reliable method to protect the PEX piping.

You can prevent the pipes from bursting or leaking by reducing the exposure to certain risks, including harsh weather conditions.

Without insulation, PEX pipes can cause trouble and frustration, not to mention high repair costs.

Insulation is vital if you want to use a reliable plumbing system like PEX piping.

Without insulated pipes, you will have to deal with unfortunate outcomes in the winter season.

It will usually be in the form of frozen PEX pipes in the crawl space.

Although PEX piping is flexible and resilient to fluctuating temperatures, it cannot hold for long without proper insulation.

PEX pipe freezing is still possible, given the vulnerable nature of plumbing systems during the cold season.

Once the temperature falls below 20 degrees, it will destroy the PEX pipes and lead to their eventual failure.

You can protect the PEX plumbing in your house by ensuring the longevity of the pipes with insulated materials.

You can also benefit from the expansion and contraction of the piping without worrying about freezing and cracking.

You can add insulation to your basement area, garages, attics, crawl spaces, and other sections of the house to prevent any problems during the winter season.

You should also consider PEX pipe insulation to limit exposure to harsh environmental conditions.

There are many ways to insulate PEX pipes—you can use foam to surround the piping because it is flexible and goes well with the material of PEX.

By cleaning the pipes with a wet cloth, you can prepare them for foam insulation.

You can also seal the PEX tubes with the help of insulation tape on the foam ends.  

Here are some important things to consider to improve the use of PEX piping in harsh weather:

PEX Pipes’ Location

If you are insulating the PEX pipes in a new home, you should consider running them through the interior walls of the house, instead of the exterior walls.

This can prevent PEX pipe freezing due to outside temperature.

If you’re considering using PEX pipe outdoors check out this article.

Your home’s inner heating system can keep the pipes from freezing and provide you with a better plumbing situation.

As you know, the pipes will freeze below 20 degrees, so you can keep the inside temperature higher to stop the freezing of pipes and let the insulation keep them safe.

Insulation of Exposed PEX Pipes

If you are not building or renovating your house but still want to use PEX piping for the upcoming winters, you can run the pipes outside.

However, you will need proper PEX pipe insulation to prevent the outside temperature from damaging the pipes.

Any exposed PEX pipe requires a minimum of R3 insulation, equal to 3/8” thickness.

If you live in a harsher environment, you will need R4 insulation, which equals 5/8” thickness.

You can insulate the pipes and secure the ends and bends with tape to avoid any problems due to incomplete insulation.

PEX Pipe Insulation Requirements

Insulation of PEX pipes is not difficult, but some requirements make the process easier and more effective.

Following are the standards that will help you improve the insulation of the pipes and prevent them from freezing:

PEX Pipe Sizing

PEX pipes come in standard sizes that range from 1/4 to 2 inches.

The length of the pipes can be anywhere from 50 to 200 feet, which makes it crucial to check the sizing before finalizing the insulation necessary.

The American Society of Testing & Materials (ASTM) requires the PEX pipes standard to be CTS, which is also required for copper and CPVC piping.

PEX pipe insulation can be the same foam size as copper piping.

The standard size is effective for PEX insulation, but it may not be completely snug because of the vague size.

A major factor that influences the fitting is trapped air space.

If the wrong fit is used to insulate the piping, the result will not be adequate.

It would be recommended to use appropriately sized insulation that can fit perfectly.

Insulation Material Type

As mentioned before, foam is the preferred material for PEX pipe insulation.

It can be flexible and match the demands of the PEX material.

An important reason to use foam for PEX insulation is the flexibility factor.

PEX is most commonly used to accommodate the curved spaces within a house so that there is no need to use connection joints.

Due to the flexible nature of foam, it can wrap around the PEX piping and protect it from freezing in cold temperatures.

The substitute for foam would be fiberglass insulation which is too rigid for PEX piping.

Insulation Fit Type

Following the standard requirements for pipe material, it’s time to figure out the perfect fit for the insulation.

There are two options for PEX pipe insulation fit that would be the best for proper use—continuous length and polytype.

Despite the differences between the two types, you will find both of them are great for pipe insulation.

Continuous length extends over an extended area, so it’s suited for continued piping, while the polytypes are better suited for post-construction plumbing.

Remember that selecting the right insulation fit is crucial for the perfect fitting of the pipe and insulation material.

Other Ways to Prevent PEX Pipe Freezing

Pex pipe freezing prevention

In addition to the insulation of PEX piping, you can use different methods to keep the pipes from freezing in cold temperatures. Following are some tips that can help you protect your PEX plumbing:

Install a Water Monitor

A good investment on your part would be to keep track of your water usage with a water monitor.

Besides monitoring the usage, it can also help you track and detect freezing conditions, appliance failures, leaky pipes, and running toilets.

Imagine how much you can save with a device that informs you about problems before they become irreparable!

Keep the PEX Hose in a Warm Location

During the winter season, the PEX hose can lead to the freezing of water and cause damage to the pipes.

You can prevent that from happening by disconnecting the PEX hose and bringing it inside the house for temporary piping solutions.

If the hose is kept in a warm location, you can prevent the PEX pipe from freezing.

Running Interior Faucet

Running the interior faucet during cold temperatures is an effective method to prevent the freezing of water or pipes.

Not running the faucet to let out the cold temperature slowly is one of the reasons PEX pipes freeze in crawl spaces during harsh weather conditions.

When the hard freeze happens (usually below 20 degrees), you can run the interior faucets to let the water flow in a small stream.

It will reduce the water pressure in the walls of the PEX pipes and prevent them from freezing beyond control.

Freeze-Proof Sillcock Can Help

Freeze-proof sillcocks are perfect for regulating water flow in the PEX pipes.

You can use these water valves for freeze resistance and prevent the water from freezing in the pipes and damaging them.

Winterizing the PEX Pipes

Owning or renting a vacation home is common for most families who prefer to spend winters in a more wintery location.

However, plumbing becomes a problem if the vacation home does not have winterized PEX pipes.

If you plan to spend the winters with your family or friends at a vacation house, you can winterize the plumbing before your visit to prevent PEX pipe freezing.

You can start with draining the entire plumbing system, including the toilets and water heater.

You can also install P traps in the crawl spaces and basements to prevent any damage to the pipes.

Maintain Room Temperature

When the outdoor temperature drops below 20 degrees, you can set up the thermostat inside the house to keep the interior space warm at 55 degrees throughout the day.

This will prevent PEX pipes freeze in crawl spaces and keep them from bursting due to harsh temperatures.

You can also use other methods to protect the plumbing system in your home–professional furnace checks, cracks sealing, cleaning gutters, and battery replacements, are some examples.

What Happens If PEX Pipes Still Freeze?

It’s possible that the outside temperature still gets to the PEX pipes despite all the measures.

What should you do in a situation like that?

The simplest thing for PEX pipe freezing is to use thawing methods to unfreeze them.

You can first inspect the pipes to see any visible cracks, and if you find any, you can contact your plumber to repair or replace the pipes.

If there are no cracks, you can shut off the main water supply and let the faucets run until there is no water in the pipes.

Once you are sure there is no water in the pipelines, you can use a hair blow dryer to unfreeze the PEX pipes.

You should keep the blow dryer a few inches away from the pipes and use your hands to check if the pipes are thawing or not.

PEX pipes can endure up to 200 degrees, so you can only keep the hairdryer to that much heat.

If you keep any area of the PEX pipe under too much heat from the dryer, you are at the risk of damaging the pipes.

Therefore, use the hairdryer carefully and thaw the PEX pipes unhurriedly.


PEX pipe freezing is common for crawl spaces, especially during cold spells.

The environment can gradually impact the pipes if they are not properly insulated to prevent freezing or cracking.

Instead of letting the winter season increase your repair costs, we suggest you insulate the plumbing of your house.

You can use foam to run along the length of the PEX pipes and close the crawl space vents during the coldest months so that you have a better chance of protecting the pipes.

You can also use other methods like winterizing the house and running the faucets to keep the PEX pipes in better shape.

And if for some reason, you end up with frozen pipes anyway, you can simply use the thawing method to get the PEX pipes back to their original condition.

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