Freeze Warning! The Admission of Incompetence
It’s “Freeze Warning” time of year again. We had our first freeze of the winter here in Atlanta last week, and I saw the sign above. I cringe every time I see one of these signs that says “Let faucets drip.” What’s worse is when those signs pop up in front of buildings with green building certifications. Yes, we have some of those here, and I drive by one on my way to the office. In either case, though, it’s hard to imagine a better way to broadcast that the incompetence of the design and construction of the building.
And then many other companies that deal with homes send out advice like what you see below, which I got from my homeowners insurance agent around the same time.
I think this is mainly a southern thing. People in cold climates generally know it’s a stupid idea to put water pipes in places that could cause them to freeze and burst. So I’m going to share some cold climate “secrets” that will prevent pipes from bursting without having to waste water and energy.
3 ways to protect your pipes from freezing
1. Get them completely inside the conditioned space. If freezes are a regular thing where you live, pipes need to be in the heated part of the house. Then, the only way they can freeze is if you lose power and can’t heat the house.
2. If they’re in a vented crawl space, encapsulate it. By air-sealing the crawl space to isolate it from outdoors and insulating the foundation walls, you’ll keep the crawl space much closer to the indoor temperature than the outdoor temperature. Then put a remote sensor for a digital thermo-hygrometer in the crawl space to monitor the conditions.
3. Wrap the pipes with insulation and perhaps install heat trace cables. If it’s just not possible to get all the pipes into warmer conditions, pipe insulation may be all you need to keep them from freezing. But sometimes that’s not enough.
And definitely don’t do this!
At least water pipes in attics are uncommon north of central Florida, but bigger buildings have fire suppression systems with sprinklers in ceilings. Some of those are “wet systems,” which are constantly pressurized with water. Those need protection from freezing. In fact, the fire code requires it. Using a dry system that lets water into the pipes only when necessary would be another way to prevent those pipes from freezing. (Here’s a good explanation of wet and dry systems.)
My mother-in-law lives in a retirement home with a wet sprinkler system. To keep the sprinkler system pipes from freezing, they’ve opened the attic hatches in the heated hallway. Ugh! That meets the fire code mandate of protecting the pipes from freezing but violates the fire code by having an open hatch that can feed a fire with oxygen.
So I got the contact info for the associate executive director and sent him an email about the increased risk of fire from having open attic hatches. I also told him about the safety issue and mentioned some of the relevant building and fire codes they were violating. The next time I went there, the attic hatches were closed. Now let’s see if they remember that lesson this year.
Stop the waste
I hate to think of how much water gets wasted by people leaving their taps running when those signs go out. Likewise with the amount of heating energy wasted when people think they have to keep the heat set to no lower than 60 or 65 degrees Fahrenheit or try to heat an unconditioned attic. If the occupants are home, that’s not an issue. But no residence in climate with freezing weather should need that much heat just to keep pipes from freezing.
So there. Freeze warning, schmeeze schmarning! Just steer around the incompetence and freeze-proof your pipes.
Allison A. Bailes III, PhD is a speaker, writer, building science consultant, and the founder of Energy Vanguard in Decatur, Georgia. He has a doctorate in physics and is the author of a bestselling book on building science. He also writes the Energy Vanguard Blog. For more updates, you can follow Allison on LinkedIn and subscribe to Energy Vanguard’s weekly newsletter and YouTube channel.
Related Articles
10 Uncommon Tips for Winterizing Your Home
Controlling the Humidity in Your Home in Winter
Don’t Compromise — Get a Low-Level Carbon Monoxide Monitor
Comments are welcome and moderated. Your comment will appear below after approval. To control spam, we close comments after one year.
They have these “drip faucet” signs all over Oklahoma too. I have a new house and it has a bathroom vanity on an outside wall that freezes if you don’t leave the doors open. I never had these problems in Illinois, Minnesota, or New York. I am not sure whether to blame the builders or the building codes for allowing such poor practices.
RoyC: Any builder who leaves pipes vulnerable to freezing definitely deserves at least some of the blame.
RoyC: recent building codes to blame? Mostly not, although I would be first to blame the codes for not being stricter. IRC section P2603 has had freezing protection requirement since at least 2000 (that’s as far back as I care to look…) and still does.
Allison: any builder who leaves pipes vulnerable deserves ALL the blame, although homeowners do silly things.
Paul: Does the IRC have specific freeze protection requirements? In other words, does it allow water lines to pass through insulated exterior walls? I suspect that some builders and plumbers think this is OK as long as the insulation is between the pipe and outside sheathing. I know from experience that that doesn’t work in extreme conditions, especially when you have a cabinet insulating the interior surface.
Allison: I have seen builders use codes to cover their butts. I asked a builder why he didn’t vent the gas fireplace or range hood to the outside. His simple response was “meets code”.
Roy: specific? Well, here is what P2603.5 says:
“In localities having a winter design temperature of 32F or lower as shown in Table R301.1(1) […] pipe shall not be installed outside of a building, in exterior walls, in attics or crawl spaces or in any other place subjected to freezing temperature unless adequate provision is made to protect it from freezing by insulation or heat or both. […]”
In other words (and it is the HVAC design temperature, btw), use adequate provision. There you have it. That’s specific! And then by “heat”, as in leaking indoor heat, like opening cabinet doors? Yeah, come on code people, you’re taking the “land of the free” a bit too literally.
If I turn my sarcasm off for a moment, maybe by “heat” they mean if a pipe is positioned deep enough inside the building envelope it is protected by the indoor heat?
Paul, I would guess that my builder would claim that he meets code by the clause that says “adequate provision is made to protect it from freezing by insulation” since the exterior wall is insulated.
Ah, yes, heat melts ice. On the bright side, people know their basic physics, after all! 😉
The homeowners insurance agent advice list above goes hand-in-hand with “start a camp fire in your living room, more or less. It reflects the state of a good chunk of our existing housing stock.
Paul: Well, that they know some basic physics is good. That they don’t go beyond that is the real problem here, though.
I will say that not concerning oneself with protecting pipes from freezing also wastes water. Once my neighbors in a 100 year old house in Asheville with minimal insulation and exposed pipes in the crawlspace did nothing during a fast freeze, and their pipes froze and burst and gushed water into the street for several hours while they slept in, which froze into a nice thick sheet of ice that made the road impassible, until my other neighbor got fed up and turned their water off for them at the road. The people who live there now are very diligent with their heat trace cables, other effective crawl air sealing was just not feasible for the age and condition of that crawlspace.
Leigha: Yeah, not every house is a good candidate for crawl space encapsulation. And even when a house is a good candidate, the owners have to shell out a few thousand dollars to make it happen and that’s not in everyone’s budget.
Allison, what makes a house a good candidate for crawl space encapsulation?
Tim: In general, it shouldn’t have any serious water problems, and you need to be careful with atmospheric combustion appliances in the crawl space. It also should have good, continuous foundation walls.
Here’s an article I wrote on the topic:
https://www.energyvanguard.com/blog/should-you-encapsulate-your-crawl-space/
Up here in NE Ohio the news suggests opening cabinet doors and dripping faucets when the air temp is roughly below 0 F. I’ve never seen a sign like that. Who is paying for it? I don’t think a sign like that would stick into frozen ground let alone not get blown over up here.
Jeremy: I don’t think I’ve seen these signs anywhere but in front of condos or apartment buildings. It seems to be a way that the developers and builders can get away with not designing and building right from the start and HOAs can get away with not fixing the problem.
“If it’s just not possible to get all the pipes into warmer conditions, pipe insulation may be all you need to keep them from freezing.”
Pipe insulation won’t protect pipes from freezing if the water is static. The small amount of heat in the water when it arrived will gradually migrate through the insulation until equilibrium is achieved. Pipe insulation can be effective, if it’s not too cold, if the water is moving.
Peter: Yeah, I was too supportive of that idea. It can work in places that don’t freeze regularly or in a crawl space or basement that always stays significantly warmer than outdoors, but it’s not a reliable solution by itself. Thanks for calling me on that.
When I was 17 we had what I think was probably the longest cold spell on record in North Texas, my mom was with her sick mom out of state and Dad was in charge – always a bad idea (the time he covered the house in sevin dust because the kitten brought fleas in – as Mom pointed out, tiny solid white kitten… no, there were possums living under the house and the fleas were only in that one spot). This does tell you what kind of house we lived in, very old pier and beam with no insulation at all.
He forgot to leave the water dripping – we had 16 days without water right through Christmas. Thankfully, the plumbing in the bathroom in the center of the house did not freeze so we could flush – where’d the water come from? We had well water and Dad hauled it in by the bucket. He cut the bottom of the kitchen cabinet out so that would just drain to the ground and we warmed water on the stove for shallow baths – I resorted to visiting friends in town.
When it finally thawed, there were little geysers all through the yard where the pipes froze on the way to the house! They were barely buried and it turned out one pipe went across the pasture to a neighbor’s from when it had been part of the ranch we lived on.
I have one more short story, the garage apartment behind my old house in East Texas did have its water left on during a deep freeze but no one was home and there was no heat so the drain froze, pushed the sink up off the pipe then the weight ripped it off the wall and broke the pipe which glaciated the bathroom, living room, front stoop and outdoor stair case – it was an amazing sight!
So maybe having heat and dripping water is called for in some situations. Alternatively and this was born out 4 years ago during Snowmageddon, just cut the water off!
Kelly: Closing the valve is only step in preventing pipes from bursting. You’d also have to drain the lines.
Here’s an interesting study from the University of Illinois showing how pipe bursts occur. Pipe bursting is caused by the extreme pressure increase due to ice expansion on the remaining (non-compressible) water in the system. This explains why sometimes the burst occurs in an area that obviously was not subject to freezing. When I was a kid in East Texas my father had a small mobile home park. Sometimes the piping would freeze under the trailer yet the burst might occur in a cabinet inside the home. And frequently we wouldn’t know there was a leak until the pipes were thawed. Having only gone there because the tenant complained of having no water.
https://www.ideals.illinois.edu/items/54859
Here’s the summary:
This research shows how pipe bursts occur. A
commonly held view, that ice growth simply pushes
against pipe walls, is not correct. Pipe bursting occurs
when 1) freezing temperatures create ice blockages in
water pipes, then 2) further ice growth applies
dangerously high pressures to a confined water volume.
This understanding of the rupture mechanism has been
confirmed in two years of laboratory and field studies
I refused to drip my pipes after buying my house. All pipes in the house were fine. However, after one particularly rough freeze (3F for a week) a 3/4 inch PVC water main broke about 100 yards from the house. The pipe was buried 2 feet as code requires, but it was near a ditch in an area shaded by numerous trees. I’m aware that I can have the entire water line to the house redone at a great cost through an insulated trenching system. Is there any other way to make sure it doesn’t happen again? I don’t want to use electricity, and I’m not going to dig 2 feet for a substantial length. Could this break have been a consequence of a neighbor having frozen pipes?
Stacy: not sure where you are, but it sounds like you’re sufficiently north to have a week in single digits and 2 feet is just not enough for a climate capable of that. You probably need to be at or below 4ft, check with your local building inspections. Also see here: https://www.hammerpedia.com/frost-line-map/
If you don’t want to redo the whole water line to the house, you could excavate to expose the existing line and insulate with rigid foam board (at least on three sides: left, right, and top). How thick and other details: you could probably find out appropriate local methods from your city/county water department (how they insulate shallow lines).
Having said that, the cost of high compressive strength foam board, the labor to install etc, might all be more than simply digging a new trench.
I’m outside Knoxville, TN, where the frost line is only 12 inches. The design temperature is 15. Around that time I noticed my dentist office and several local gas stations closed due to water pipe bursts. My plumber said that he’d seen one line buried 3 feet for extra protection.
Stacy: according to NOAA data for Knoxville airport, last time there were at least 3 consecutive days with lows below 10F was 1/16-18/2024 (low of 8 on 1/16, 0 on 1/17, and 5 on 1/18, with highs in the mid 20s to low 30s). Before that, it was 1/6-8/2014, 2/3-6/1996, 1/18-20/1994, and then in 1989, 1988, 1985, 1983, 1982, 1978, 1977, and so on. Find someone who laid water lines in the 1980’s and you’ll be good 😉
You’re not anywhere near as far north as I thought, and 24″ should’ve been fine, unless the cover was affected by soil conditions favorable to heat transfer (dense, dry soil). Discussing all possible heat transfer scenarios in different soil conditions combined with temperatures leading up to the event would be a whole research project. I’d rely on local empirical knowledge and add 12″ to that to feel better, so maybe the plumber with 3ft was right?
If there is a way to add soil on top of that 100 feet of pipe?
Perhaps making it like a slight hump/berm along the length of pipe?
Even 6-8” could perhaps make it safer from bursting the next time?
It could be less expensive than digging a trench?
Could be done in stages if diy – 30 feet one season, then another 30 feet, etc
If the space is wide open you could perhaps incorporate inexpensive solid extruded foam prior to adding soil – not sure if termites is the issue with foam in the South
I’ve had termites in the yard and under the house before. It’s my understanding that the trouble with foamboard is that termites can tunnel through it, but it’s not like it feeds them. I was concerned that wet foamboard can be involved in chemical leaching, possibly negating the advantage of bora-foam and other termiticide treated foams.
The yard is sloping about 15 degrees near the area of the pipe breaking, so I wonder if it was just failure to keep a good horizontal distance as well. Add it in the nearby ditch and I can consider erosion .
The Knoxville Utility Board (which doesn’t have jurisdiction as I’m in the next county) requires mains to be buried 3 feet and residential connections only at least 2 feet. I assume that they are ok with occasionally replacing residential lines after unusually bad freezes but cannot accept replacing their main water line.