Explosive Problem: Frozen Pipe in Basement Wall

  • Thread starter russ_watters
  • Start date
In summary, the homeowner is working on a basement and has an issue with the water freezing in the pipe. The hose bib valve is frozen and won't open, and there is a possibility of a break.
  • #1
russ_watters
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No, it isn't that stomach flu that's going around.

See pic. I live in an end-unit townhouse and I'm finishing my walk-out basement, which was completely (illegally?) un-insulated prior to me starting. The wall on the left is the back wall. Six feet down is an outside hose bib. The pipe runs up the inside of the back wall and then across the ceiling, between the joists. Just inside the access hole is a shutoff valve for the hose bib. The side wall (with the access panel) is the "wet" wall, with my main sewer pipe enclosed in it, There is about 6" between the concrete wall/foundation and the drywall. All of the concrete foundation is covered inside by 5/8" foam sheets and the rest of the wet wall is packed with standard 4" insulation. But I cut the insulation around the hose bib pipe, so that is right up against the concrete, outside of the insulation.

The lighted electrical cord is for heat trace, which is wrapped around the valve and 6" of piping on either side. Then that is covered with a piece of molded foam insulation.

So here's the problem. It was 10F here last night, got up to 20F today and is going to be 10F again tonight. A couple of months ago, I remembered to close the isolation valve, but forgot to open the hose bib to let the water out or plug in the heat trace. Last night, I went outside to open the hose bib and nothing came out...but forgot about the heat trace. Clearly, water is frozen in the pipe. I should have investigated further, but didn't...

Tonight, I opened the access panel and found a little bit of water and ice on the insulation. The pipe insulation is cupped upwards and held a little more water. Altogether, no more than an ounce or two. The hose bib valve is now frozen and won't move. An infrared thermometer recorded temperatures well below freezing in the wall cavity.

I don't think any pipes/joints have burst, but I don't want them to, so I was hoping to thaw out the frozen pipe. So I pulled aside the insulation, turned on the heat in the basement, plugged in the heat trace and stuck a hairdryer on low in the wall. Thinking perhaps the pipe had pulled out of the valve (I can't see it and couldn't really feel it), I closed the isolation valve.

Bad idea. A half hour later, I checked on it and the pipe was too hot to touch. I opened the valve to test it and it made a "thunk" from depressurizing itself. Hopefully this means there were no leaks (not sure if the little bit of water was condensation?), but I certainly don't want to break the pipe by heating it and I'd really like to thaw it while I'm here to avoid any surprises when it does thaw. It's been more than an hour and nothing is coming out yet and the hose bib valve is still frozen. So...

Could the water in/on the insulation be condensation? It's pretty dry here when it is cold...
Could it have squeezed out through the seals in the isolation valve without destroying the valve/bursting a pipe?

Opinions on what I should do? The outside hose bib valve may be frozen for the next week, but the inside isolation valve works. If I don't have success I guess I'll let the system cool a bit, then close the isolation valve. But I'll be pressurizing that last 6' of piping and I'd really rather not.

For now, the isolation valve is open, and I'm checking every few minutes to see if anything is coming out either into the wall or outside. Nothing so far.

Ugh.

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  • #2
Ffrrrrrrrrrrrrrrrrrrrriiiiiiiiiiiiiiiiiick!
 
  • #3
If it's any help, remember the thing that bursts pipes is not freezing them solid. It's freezing them at two positions and trapping some water in between, and then freezing (and expanding) the trapped water.

If the water can get out of the way some place as the ice accumulates, often there's not a problem.

I don't understand US plumbing terminology well enough to relate that to the situation you have!

Ice contracts as it gets colder, like almost everything else. Water expands very slightly cooling from 4C to 0C (specific gravity change 1.0000 to 0.9998) but the big volume change is between water and ice (s.g. 0.9168 at 0 C)

EDIT: didn't see your post #2 before posting this - but it seems to translate as bad news :cry:
 
  • #4
:cry:

Not sure if I discovered a break or caused one, but...

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  • #5
Uh, oh.. looks like it turned into a wet problem. Bad situation, it would require breaking down the wall to fix it? At least you know where it's coming from, sometimes there are leaks where water takes a long path before appearing in another location.
 
  • #6
I'll need to break down the wall (that I built!) to fix it. I'll do that this spring. For now, it seems to be secured by the isolation valve above the leak.
 
  • #7
Arg. Good luck Russ.
 

Related to Explosive Problem: Frozen Pipe in Basement Wall

1. What causes a frozen pipe to explode in a basement wall?

When water freezes in a pipe, it expands and puts pressure on the walls of the pipe. If the pipe is already weakened or damaged, this pressure can cause the pipe to burst or explode. In a basement wall, the frozen pipe may be under even more pressure due to the weight of the building above it.

2. How can I prevent a frozen pipe from exploding in my basement wall?

The best way to prevent a frozen pipe from exploding is to prevent it from freezing in the first place. This can be done by insulating pipes in your basement and keeping the temperature above freezing. In extreme cold weather, you may also need to open cabinet doors to allow warm air to circulate around pipes.

3. What should I do if I suspect a frozen pipe in my basement wall?

If you suspect a frozen pipe in your basement wall, it is important to act quickly. Turn off the water supply to the affected area and try to thaw the pipe with a hairdryer or space heater. Do not use an open flame to thaw the pipe, as this can be dangerous.

4. What should I do if a frozen pipe in my basement wall has already exploded?

If a frozen pipe in your basement wall has already exploded, turn off the water supply and assess the damage. Call a professional plumber to repair the pipe and check for any other potential issues. You may also need to contact a water damage restoration company to clean and dry the affected area.

5. Can a frozen pipe in a basement wall cause other problems besides exploding?

Yes, a frozen pipe in a basement wall can cause other problems besides exploding. If the pipe does not explode, it can still cause damage by bursting or leaking once it thaws. Additionally, the frozen pipe can cause a decrease in water pressure and make it difficult to access water from that area of the house.

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