Frozen Pipe inside wall

Looking for suggestions here -

I have a basement that's about three quarters finished so I have access to where all of the plumbing originates from.

There is a bathroom in the basement - the water pipes come from the unfinished space, go into the finished ceiling space, branch off to the kitchen and an upstairs bathroom and also go through the ceiling of the basement bathroom, down to an outside wall, and to the sink and toilet.

The house is insulated pretty well, but when the temperatures dip down into the 20's, the pipes for the basement bathroom that go down the outside wall freeze.

When this happened last year I put a space heater in the room, opened the faucet, and several hours later, water was flowing again. Since then, when it gets really cold out, I leave that faucet dripping.

Well, last night it got really cold (about 5 degrees) and I forgot to leave that faucet dripping.

Is there a faster or better way to get that pipe thawed out? Is there I way I can prevent this from happening in the future? Leaving it dripping works if I remember to do it, and wastes a lot of water.

By the way, this is all Flowguard Gold CPVC piping.

Thanks for your advice.

Re: Frozen Pipe inside wall

You could use one of the heat tape systems they make for pipes. Low current draw and keeps them warm enough to not freeze...

Re: Frozen Pipe inside wall

I was looking at them, but you're not supposed to install them inside of a wall or within .5 inches of insulation. This pipe is inside the wall and hopefully, has insulation within .5 inches of it.

I'm about to open up the wall to see what exactly is going on.... when I pull the pipe flange away from the wall where the pipe enters it, I feel cold air...

Re: Frozen Pipe inside wall

Oh, I misunderstood...I thought the pipes were running down the inside of an outside wall (vs. in the wall). If they're in the wall it should be an easier fix. Insulate, insulate, insulate...

Re: Frozen Pipe inside wall

Heat it with a hair dryer, or heat gun to thaw it out. I don't know why you couldn't use heat tape, they use them all the time in Mobile homes, & trailers. Another idea, I know it's not the best, but is to put a small vent in the wall so room heat keeps it from freezing.

Re: Frozen Pipe inside wall

Can you reroute the pipes to the inside of the wall? If you think it would look to ugly you could build something around them that looks nice somehow.

Re: Frozen Pipe inside wall

Get some sheet plastic outside and fill the gaps with spray foam. You have cold air getting in and a 1/8" gap is enough to freeze a pipe.

Re: Frozen Pipe inside wall

I think Bob_VT nailed it, and I appreciate everyone's suggestions.

I couldn't stand it, and I was pretty sure that the pipes ran behind a mirror (perfect! I hate drywall work!) so I took the mirror down and cut the wall open. The pipes thawed out quickly once the wall was open (probably 30 minutes before both hot and cold started running).

Turns out that the builder put the insulation between the pipes and the drywall. It should be between the outside house wall and the pipes.... arrrgh. To add insult to injury, the exhaust fan vent runs outside the house in the same stud bay that the pipes go down in. The fan vent louver outside the house wasn't closing all the way (probably 2/16ths open) plus it's only a small piece of sheet metal which has probably no insulation value and some of a caulking around the vent was cracked.

So, I put foam rubber pipe insulation around all of the pipe that I could reach in the wall, stuffed in as much R-13 batting as I could reach and also stuffed it around the vent flex-hose where it exits the house the best I could. I also pulled the old aluminum vent off the outside of the house (what a pain! It was super-caulked on!) and installed a new plastic one that seems to close better (but still has no insulation value...). I used expanding spray foam around the whole thing from the outside to make sure that everything is good and tight. Tomorrow, once the foam is dry, I'll caulk around it to make it pretty and seal up any gaps that the foam may have missed.

So, now I'm debating with myself if I let it go overnight and see if this fixes it or if I should leave the sink dripping just to be safe....

Re: Frozen Pipe inside wall

jsfinn said:

So, now I'm debating with myself if I let it go overnight and see if this fixes it or if I should leave the sink dripping just to be safe....

Click to expand...

If you leave it dripping, you'll never know if you got it. I say go for it...no guts, no glory...

Re: Frozen Pipe inside wall

jsfinn said:

I think Bob_VT nailed it, and I appreciate everyone's suggestions.

stuffed in as much R-13 batting as I could reach and also stuffed it around the vent flex-hose where it exits the house the best I could. ....

Click to expand...

I hope you didn't compress the insulation and pack it tight in there. I was taught that when you compress insulation, it looses insulating efficiency ( R factor )..

wncrjb

Re: Frozen Pipe inside wall

I think you got the right idea about how to fix things now.
They also make what is known as a thermal plug-in fixture that turns on the electric power to a heater of sorts when the temp drops down to about 34-35 degrees.
If you decide to leave the water dripping, it really does not take much movement to keep it from freezing.

Re: Frozen Pipe inside wall

First of all, 5 degrees isn't cold.

Having said that, is this bathroom in the basement? I am unclear about that. If it is, the cold air is probably infiltrating between the sill plate/rim joist and the foundation. In colder climes, say Wisconsin, the entire perimeter of the floor system is insulated with 6" batts.

The following remarks are made assuming that it is a basement bath; if not, read no further. What you have done may well solve the problem. To be safe, stuff insulation up toward the first floor. Compaction will be less of a concern; you just want to block the flow of cold air. To improve the heating of the house and knowing that part of the basement is finished, insulate whatever exposed rim joist area that you can reach.

Re: Frozen Pipe inside wall

wncrjb said:

I hope you didn't compress the insulation and pack it tight in there. I was taught that when you compress insulation, it looses insulating efficiency ( R factor )..

wncrjb

Click to expand...

I didn't jam pack it - I know to leave it loose but cover everything. It is compacted a little bit between the pipe and the outside wall but there isn't any getting around that. Either way, it's better than it was.

Re: Frozen Pipe inside wall

gss036 said:

I think you got the right idea about how to fix things now.
They also make what is known as a thermal plug-in fixture that turns on the electric power to a heater of sorts when the temp drops down to about 34-35 degrees.
If you decide to leave the water dripping, it really does not take much movement to keep it from freezing.

Click to expand...

Thanks. I was looking at those wrap around pipe heater things but there are two problems -

1. You can't install them in a finished space and they need at least 1/2 inch clearance between them and insulation.

2. It would look kind of funny having an electrical cable hanging out of the wall.

I think I'm going to let it drip tonight and once I can finish up the job with the outside caulk tomorrow, maybe turn off the faucet and see what happens. I just know that if it freezes overnight, I'll be stressed out about it all day at work tomorrow not being able to keep an eye on it.

Re: Frozen Pipe inside wall

burroak said:

First of all, 5 degrees isn't cold.

Having said that, is this bathroom in the basement? I am unclear about that. If it is, the cold air is probably infiltrating between the sill plate/rim joist and the foundation. In colder climes, say Wisconsin, the entire perimeter of the floor system is insulated with 6" batts.

The following remarks are made assuming that it is a basement bath; if not, read no further. What you have done may well solve the problem. To be safe, stuff insulation up toward the first floor. Compaction will be less of a concern; you just want to block the flow of cold air. To improve the heating of the house and knowing that part of the basement is finished, insulate whatever exposed rim joist area that you can reach.

Click to expand...

5 degrees is plenty cold.

It is a bathroom in the basement and I should have mentioned that the basement is only about 1/3 underground.

Is the sill plate/rim joist that 2xsomething wood that sits horizontally on the concrete foundation wall? How far down do you figure the frost line is?

I'm 99% sure that the freeze was happening in the ceiling of the basement, probably 4 or so feet above the concrete foundation.

Re: Frozen Pipe inside wall

I agree with that 5 degrees is cold. We were down to 19 here last night with 55 mph northeast winds howling. Now that creates problems. Stopping the cold air infiltration is the most important. The worst we have ever had it here in the 40+ years was about -10-15 degrees w/65 substained and 90-100mph gusting. I ended up having to do some plumbing after that.
If I remember right the pipe that you have will not burst if frozen, that is a real plus. They are starting to use that kind of pipe here now because we do have a tendancy to loose power for several days at a time. I do have a generator and usually have at least 25 gallons of gas in the boat just in case.
Good luck and keep us posted as we can all learn from others experiences.
I think it is said that a wise man learns from others mistakes.

Re: Frozen Pipe inside wall

You said you put foam rubber insulation around the pipes. You should not do that. You insulate between the pipe and the outside wall and leave the pipe exposed to the inside heat as much as possible.

Re: Frozen Pipe inside wall

jsfinn said:

Is the sill plate/rim joist that 2xsomething wood that sits horizontally on the concrete foundation wall? How far down do you figure the frost line is?

Click to expand...

Yes. The frost line is probably less than 4'. That is what is commonly agreed to here in WI. I guess that you are at 3' or less since your foundation is only 4.5'-5' below grade. For your pipes to freeze due to the cold migrating into your house below grade, the temperature would have to be severely cold for quite a spell. The weakest point is that basement wall/floor system connection. If you felt cold air coming from the hole in the wall, a breeze was positively pushing it. The solution is to insulate the cavity behind the pipe floor to floor. The unfinished area in the basement could benefit from the same treatment.

The farmer approach in the drafty old homestead is to place straw bales around the entire foundation. That is frowned on in the newer subdivisions unless you are in the UP. or MN.

Re: Frozen Pipe inside wall

Update -

Well, it's been cold, and I've been too chicken to not let the faucet drip...

I did get in touch with the builder (I'm the 2nd owner, the house is 8 years old, and has a 10 year warranty) and convinced them that this is a real problem and it really is covered (they didn't want to talk to me last year when this happened - but I hadn't cut the wall open yet).

They came out today to see what was going on and agreed that the insulation isn't properly installed. They are going to send out a repair guy next week to open up the rest of the wall to make sure that it's all insulated properly (I'm not sure I got my insulation all the way up in to the ceiling - couldn't reach that high with the hole I cut) and then send out a drywall guy to patch and paint.

That's great news because I *hate* doing drywall work!

Re: Frozen Pipe inside wall

I hear you on the drywall thing. I will hang it all week but the taping and sanding belong to someone else.

Good news on the warranty!!!