What is wrong with my house? Frozen pipes are the symptom...
January 6, 2014 3:30 PM   Subscribe

We are in Illinois and gripped by the coldest weather in 20 years. Our house is 15 years old, we've lived in it for 2. With the cold some plumbing has stopped working to one toilet and one bathtub. Weirder, ice has formed around the drain of the tub. Inside. We had a plumber out and he was at a loss. More details inside. Need to know what is wrong and what are our next steps?

Our house is two story. Before going to bed last night the biggest fear we had was frozen pipes. Online we read the pipes most at risk are on external walls, and there are only three plumbed items we have on external walls -- Kitchen Sink, Kitchen Dishwasher (both 1st story) and master bathroom toilet (2nd story, a bit above kitchen). We set the kitchen sink to drizzle overnight but thought there was nothing we could do about the toilet.

At 3:30am I check the toilet and sure enough, no water (it worked at 10 pm). We check the shower and both sinks in that bathroom, all work (spouts on inner wall perpendicular to the outer wall). We then try the tub located between the shower and the toilet and after a couple drips from behind the faucet the tub did not work either. This tub is under a window, next to the outside wall, but the faucet is at the foot, again perpendicular to the outer wall.

We figured the pipes were frozen and perhaps the pipe to the tub went up the outside wall and hence why it would be frozen. We then called a plumber as we feared the pipes leaking into the basement.

The plumber came out and said there was nothing he could do as the pipes were all behind drywall. He showed us where the main shut-off is for the house and told us to run the heat to thaw the pipes. He told us there's likely only one run of pipes to feed the entire bathroom (though he had no way to prove that...again, drywalled in) so he thought the pipes went to the sink and shower, then along the outer wall to the tub and toilet, so the freeze would be confined to that tub/toilet area.

We noticed the few drops that had dripped into the tub, however, had turned to solid ice. Touching the tub it was really cold, a good 30-40 degrees colder than the room. We had the heat at 70, that bathroom always runs a bit colder but never freezing. However the tub bottom froze the ice.

All day we ran a space heater in that bathroom, plus we ramped the heat on that story up to 80. It was easily 90 degrees in that bathroom, but the pipes still do not work and the bottom of that tub (only 2 feet from the space heater) is still cold. We put more water in the tub...it will not drain (why would the drain pipe freeze? The tub has not been used in many months). The scalding hot water we put in the tub instantly dropped to icy temperatures but has not turned to actual solid ice (yet).

We looked outside and see no breech in our siding. What is going on with these pipes? Why would a drain pipe stop working when it would have been perfectly dry, and why would these other (theoretically frozen) pipes be so cold as to not thaw in a room where the ambient temperature is hotter than hell?
posted by arniec to Home & Garden (8 answers total)
Drain pipes are vented to the atmosphere, so I'd guess the cold air is getting in the vent and really cooling down the pipes. Are your drain pipes metal or PVC? If you had a slow drip down the drain, it could have frozen from the cold pipes.

Depending on insulation techniques, the temp in the room may not be reaching your plumbing. More hot water is probably the answer.
posted by hwyengr at 3:43 PM on January 6, 2014 [1 favorite]

I would suspect that there is cold air directly entering the floorspace underneath the bathroom.

There could be an open vent of some sort. For instance, I've seen dryer vents mounted on the exterior, but no actual venting pipe attached. The vent simply opened to the interior space.
posted by Thorzdad at 3:51 PM on January 6, 2014 [3 favorites]

One hint in your explanation is that "the tub has not been used in many months." That means that the trap, normally filled with water, probably dried out, leaving a clear airway for freezing air to migrate from the vent stack (a pipe which sticks up out of your roof and allows the pipes in your house to drain) directly into your tub.

You don't say when you first tried to drain the tub, but if the first water that went down that drain was cold, there's a good chance it hit the extremely cold trap, stagnated there, and froze. You mention putting hot water into the tub, but it sounds like you had the drain closed when you did so. If you haven't already, try pouring hot water down the drain, to try to thaw the ice plug in the trap.

Other than that, it sounds like you're doing everything right. You probably only have a small ice plug somewhere in the supply line, but, once frozen, it can take an amazingly long time for ambient heat from within the house to overcome the extreme cold from the (probably under-insulated) outside walls.
posted by dinger at 3:51 PM on January 6, 2014 [7 favorites]

My guess is that whoever built your house did not insulate between the tub and the exterior wall. Depending on what it's made of its probably acting a lot like a window right now, when it's really cold ice will build up on the inside of glass windows no matter how hot the room. Best suggestion is to get a fan in there blowing air directly into the tub to warm it up. And keep a close eye for leaks as it starts to warm up!
posted by fshgrl at 3:54 PM on January 6, 2014 [1 favorite]

I doubt the drain is freezing because of the vent pipe. You say the whole tub bottom is freezing cold. So probably there is just very poor insulation, or none, between the cavity space under the tub and the outside wall.

Your best option is probably to keep the heat up high and wait for the warmer weather which is supposed to come tomorrow or Wednesday. If you're in luck, it all thaws out without damage.

Option B would be to figure out where the pipes run in the walls, open them up and thaw with hair dryers.

Regardless, get an energy audit done (winter is the best time for this) and remediate the insulation. You'll save a lot of money in future winters.
posted by beagle at 3:56 PM on January 6, 2014 [3 favorites]

Seconding @fshgirl's theory that your builder did not insulate between the tub and the interior wall.

For areas where you can see pipe, putting some heat tape around the pipes might also be a good preventive. Those IL winters are no joke.
posted by hush at 4:20 PM on January 6, 2014 [1 favorite]

Is your master bath over an attached garage? Sometimes they won't insulate/insulate properly between the ceiling of the garage and floor of the 2nd story. Another thing to consider.

Certainly these problems would make me get an energy audit.
posted by sbutler at 7:16 PM on January 6, 2014 [3 favorites]

I grew up (and still own) a house with an exterior wall pipe. It feeds the whole house. A temp fix is once you get the water running to let it drip a bit until you can get someone in to fix it.
posted by beccaj at 7:47 PM on January 6, 2014

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