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12 Tips To Prevent Pipes From Freezing in a Crawl Space

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


12 Tips to keep pipes from freezing in crawl space (most are weekend DIY projects; others require professional help):
  • Insulate pipes
  • Insulate crawl space
  • Close vents
  • Seal air leaks
  • Keep garage door closed
  • Keep house warm
  • Open kitchen cabinets
  • Use heat tape
  • Use heat cable
  • Use space heater
  • Leave water running
  • Drain pipes

1. Pipe Insulation

If the pipes in your crawl space are exposed, the first thing to do is insulate them. Depending on your climate, this may solve your problem.

In more severe climates, this is only step one in preventing the pipes from freezing in the crawl space, and you will have to utilize another one or more of the suggestions presented below.

The recommended pipe insulation thickness is around 3/4″ (19 mm).

Insulated metal pipe with a roll of insualtion

Foam Rubber Insulation

One of the fastest ways to insulate pipes is by using pre-split and self-sealing foam rubber insulation.

There are various options when it comes to foam rubber insulation. Armaflex is a good brand that you can check out.

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Using Armaflex compared to polyethylene foam insulation (which we will also look at) will save 30% on labor time. You save time because it is extremely flexible it is possible to fit it around bends in the pipe.

Polyethylene foam requires special angled pieces for these bends, meaning that there will be many places where the foam doesn’t fit together perfectly. This lowers the insulation efficiency and allows the pipes to freeze sooner than they would with continuous insulation.

And, of course, Armaflex is not your only option.

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Last update on 2024-05-29 / Affiliate links / Images from Amazon Product Advertising API

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

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

HVAC 1 1/8" Armaflex Copper Insulation 1" Thick Nominal Wall 6ft Long

Armaflex also comes in other forms like sheets, sleeves without the split, and long coiled sleeves.

The coiled sleeves are good if you have a pipe that is longer than 6.5 ft (2 m) that needs some love and care. Just cut the length from the coil and you will end up less wasted material).

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

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

Rubber sleeve insulation can be used outside since it is mold-resistant.

However, 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. Without this coating, it will crack and crumble after a while.

Rubber foam insulation is also an environmentally friendly way to go since it is fiber-free and CFC-free with an ozone depletion potential of zero.

Polyethylene Foam Insulation

Polyethylene foam insulation is tempting price-wise. But it can shrink with the heat from pipes, leaving air gaps. This is not optimal for best insulation results.

Furthermore, 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 (amazon link).

However, polyethylene foam insulation is certainly better than none.

Frost King IT30/8 Rubber Insulation Tape, 2in Wide x 1/8in Thick x 30ft Long, Black

2. Crawl Space Insulation

Insulating the crawl space is quite a time-consuming project since access is limited and work under crawl space takes much longer than normal.

Luckily, in most cases it is not necessary to insulate the entire crawl space.

It is enough to build a small compartment for the water heater and use heat cable and insulating sleeves for the pipes that run out of the insulated compartment.

Crawl space with exposed insulation and an insulated pipe.jpg

While partial insulation is still not the easiest job, 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.

3. 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, so 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, which can compromise health.

Equally as concerning is if your house has a wooden structure, the moisture can start to rot it.

As soon as the weather starts to turn, you should adjust the crawl space vents. 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.

Covered crawl space with hvac pipe

4. Seal off Other Air Leaks

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

5. 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.

6. 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.

Infographic about turning down the house temperature when leaving the house could make your pipes freeze easily, hvac, heating.jpg

7. 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.

8. Heat Tape

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.

You should not insulate over heat tape.

9. Heat Cable

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.

Frost King HC6A Automatic Electric Heat Kit Heating Cables, 6 Feet, Black

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.

10. Use a Space Heater

In an emergency situation, a space heater (amazon link) 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.

andily Space Heater Electric Heater for Home and Office Ceramic Small Heater with Thermostat, 750W/1500W

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.

11. 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.

12. 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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