12 Tips To Prevent Pipes From Freezing in a Crawl Space?

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When living in an area where the winter means snow, and temperatures drop below freezing point, it is more than possible that you can encounter frozen pipes in a crawl space

Here are 12 tips to keep your pipes from freezing in the crawl space. Most of them are doable over the weekend as a DIY project, but others require professional assistance.


Pipe Insulation

When pipes in the crawl space are exposed, the first thing to do is insulate them. Depending on your climate only insulating the pipes is not enough and extra measures need to be taken.

If water freezes in the pipe, then lack of flowing water will be a minor problem. The expanding ice will most likely break the pipes or fittings. The water damage that follows can be very expensive and time-consuming to eliminate.

Recommended pipe insulation thickness is around 3/4 inch (19 mm)


One of the fastest ways to insulate pipes is by using Class O Nitrile Foam Rubber Insulation(Armaflex Class O Pipe Insulation)  pre-slit, and self-sealing.

Using Armaflex compared to Polyethylene foam insulation will save 30% on labor time. Since it is extremely flexible it is possible to fit it around bends in the pipe.

With polyethylene foam you must have special angle pieces for that, this means that there will be many places where the foam doesn’t fit together perfectly and the insulation efficiency is lower and the pipes will freeze sooner.

Armaflex also comes in other forms like sheets, sleeves without the split, and long coiled sleeves. (Good if you have a longer than 2m pipe that needs some love and care, just cut the length from the coil and you will end up less wasted material).

This insulation will be helpful all year round, in the winter it prevents frozen pipes and in summer it helps to avoid condensation.

There will be considerable energy savings on the hot water pipes. Armaflex sleeves reduce energy losses by up to 87% compared to no insulation at all.

Armaflex sheets are good to use for the water heater tank or other irregular shapes that need insulation. It is a lightweight and flexible insulation product, that works for all kinds of applications.

Read more on installing a water heater in a crawl space.

It can handle a little less heat when used on flat surfaces 185F°(85C°) and around pipes it can handle temperature up to 220F°(105C°)

Rubber sleeve insulation is also perfect to use outside since it is mold resistant.

Please remember, while it can be used outdoors, it is not UV resistant and needs extra protection from the sun. This can be achieved by Armafinish 99 paint. Otherwise, it will crack and crumble after a while.

It is an environmentally friendly way to go since it is fiber-free and CFC free with an ODP of zero. (It will not infect the ozone layer in a negative way)

Polyethylene Foam Insulation

Polyethylene foam insulation is tempting price-wise. But it can shrink under the heat from pipes and leave air gaps, and that is not optimal for best insulation results.

As we said earlier it is not very flexible and special pieces must be used for bends in the pipe. Whenever you connect two separate pieces of foam the connection point should be taped with insulating tape.(link to Amazon)

Crawl Space Insulation

In most cases it is not necessary to insulate the entire crawl space, it is enough to build a small compartment for the heater and use heat cable and insulating sleeves for the pipes that run out of the insulated compartment. This is quite a time-consuming project since access is limited and work under crawl space takes much longer than normal.

At the same time, it will prevent a massive headache in the future. It is not fun to deal with the insurance companies whose help you will need to fix the water damage and burst pipes.

Insulating the entire crawl space will be very expensive and not practical. The cost will depend on the size of your crawl space, climate, and, how accessible the crawl space is.

Close The Vents

Closing the crawl space vents for the cold season might be enough for milder climates. However, ventilation is very important in a crawl space and the vents should not be closed completely.

In most cases, you will find that building codes even require crawl space to have ventilation openings. This is to make sure that the moisture does not have a chance to build up and cause mold or mildew. Even worse, if your house has a wooden structure the moisture can start to rot it.

When the weather gets cold it is helpful to close crawl space venting holes.

I find it helpful to mark those kinds of things in my calendar as a yearly event, so I will never forget to close/open the vents.

Seal off other air leaks

Do not forget to close and insulate windows and other openings.

Make sure to close garage door

Many households have water pipes that run through the garage and crawl space.

Sometimes in a hurry, we can forget to check if the garage door is 100% closed, and it can end with frozen pipes.

Keep Your House Warm

Sometimes we leave our homes for more than a day and it seems like a good idea to lower or turn off the heat to save money on the electric/gas bill. That’s a no-go. The heat inside the house will also move to the crawl space through the pipes and ducts and will prevent them from freezing.

When leaving home for a longer period do not turn down your house temperature. When lowering the temperature inside the house, the crawl space temperature will drop significantly and pipes can freeze more easily.

Open Kitchen Cabinets

It is wise to open your kitchen or other cabinets where the pipes that go down to the crawl space are located. The pipes in the cabinets will warm up and the heat will transfer to the crawl space.

Heat Tape

Wrap-On Pipe Heating Cable - 6-Feet, 120 Volt, Built-in Thermostat, Low Wattage - 31006

It is not recommended to use heat tape in a crawl space. There are many people who say it is ok to use it but they forget to mention that using heat tape in a crawl space is a fire hazard.

Heat tapes are good to use in the places you can keep your eye on them. Insurance can refuse payment for fires caused by using heat tape in concealed locations.

Heat Cable

Heat Tape Pro for Ice Dam Prevention Heavy Duty - Self-Regulating - Plug-in Ready Heat Cable - 120V, 6 watts/FT (75 Feet + 10 Foot Cold Lead)

Using a heat cable(Amazon) is an excellent way to prevent the nightmare of freezing pipes and water damage.

In-fact I use a 30 ft. heat cable under my own house for the main water line. I have the pipes just sitting on the ground(open crawl space), it has kept the water flowing even when the outside temperature drops below –22F°(-30C°).

I would recommend buying a slightly more expensive cable, the cheap ones just don’t last, I have gone through 2 cheap cables before I bought a quality cable.

I would not recommend buying this from any big box store, they usually carry the cheaper and lower quality cables. It is a pain to replace. Especially when the pipe is frozen and it is -20 outside.

So go to your local plumbing store and ask for a high-quality heat cable. Expect to pay twice as much, but it will be a good investment.

Use a Space Heater

Portable Electric Space Heater with Thermostat, 1500W/750W Safe and Quiet Ceramic Heater Fan, Heat Up 200 Square Feet for Office Room Desk Indoor Use

In an emergency situation, a space heater(amazon) can be used to prevent frozen pipes in the crawl space. This is not a long-term solution, as animals or wind could trip over the heater or worse move it next to something flammable.

Many people think that using a space heater in the crawl space will heat up your home as well. This is not the case. Most likely your floors are well insulated and the extra heat from the crawl space will not reach your living area.

Never leave the space heater unsupervised in a crawl space for extended periods of time.

Leave Water Running

Sometimes, either because of financial reasons or other reasons you may not be able to permanently fix the problem. Leaving your tap running can help to avoid frozen pipes, without any upfront costs.

Water needs to be flowing, a trickle is not enough. It is important to have both cold and warm water flowing from the tap. This can be achieved on a single lever tap by moving it to the middle.

This definitely is not environment friendly and will raise your utility costs, but until a better solution is found it will help.

Drain The Pipes

Turning off the main water valve and draining all the pipes can be a solution when leaving for a longer time.

It is time-consuming and a lot of work but at the same time you do not need to worry, and can be sure that you don’t need to deal with a disaster upon returning.

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