Plumbing gremlins

[Sibling Lambicus the Toluous]

I know there are a few knowledgeable plumbers on here.  Hopefully someone can shed some light on my problem.

Last night, the cold water in my bathroom stopped working.  I went upstairs to get ready for bed, went to brush my teeth, and nothing.  Hot water works fine, but no cold water.  Same for the bathtub, shower and toilet, but everywhere else in the house is okay.

Possibly pertinent details:

- there's no flow at all... not even a little bit.  When I open the faucet, I don't hear anything; no gurgling, no flow, nothing.
- everywhere outside the one bathroom, everything works just fine: good flow on both hot and cold with no change from before.
- the house is about 10 years old, so all the pipe is copper in hopefully good shape; no galvanized or anything like that.
- it got really cold yesterday, though I don't think (or maybe "I hope" would be more accurate) that the pipe to the bathroom is in an outside wall.
- I didn't notice any water problems prior to this.  Yesterday morning, I had good flow on hot and cold, but yesterday afternoon, nothing on cold.
- the shower acted a bit funkier than the other fixtures.  At the sink and the bathtub, I have good flow on hot and nothing on cold.  At the shower, I now have low flow on hot and nothing on cold.
- I don't think it's leaking in the walls or anything like that.  There are no signs of water below the bathroom or anywhere I think the pipe might run, and with all the taps in the house shut, the water meter doesn't move.

I slept on the problem and came up with an idea this morning.  Assuming that it was a blockage that might be dislodged, I closed the shutoff on my water service at the meter and drained down the water level in the cold water pipes at the basement laundry tub.  Then, I opened up the bathtub faucet upstairs and opened the shutoff as quickly as I could, hoping that a bit of water hammer would work it loose - no effect.

So... it seems to me like it's some sort of blockage, but the question in my mind is what kind of blockage and what do I do about it?  Has anyone run into anything like this before?

[ivor]

Wow!  That's really weird.  Did it get below freezing? Is there a shut off valve for the cold water somewhere?

[Bob in a quantum-state-of-faith]

Well, that's certainly weird.

My first knee-jerk response is to assume that pipes have frozen in or near your bathroom. 

Is your house a slab or do you have a crawl space?

If the latter, your foundation vent near your bathroom may be open, allowing freezing air under that portion of your house, and this could account for all your symptoms.  Draining everything would not un-freeze things, either.  Only closing the vent, and letting the pipes thaw will.   (if, indeed freezing is the issue)


One symptom you can verify, is the floor in your bathroom unusually cold?  (i.e. colder than elsewhere in your house).   Try walking around the perimeter of your house, and look for tiny "windows" or openings to the crawlspace.  Covering these in the winter is a good idea, and a simple sheet of 1" thick styrofoam works wonders.   But any material that covers the hole should work.

......

If your house is on a slab, then the problem is different. 

Edit:  you said basement?   Hmmm....let me think about that...

If you really think it's blockage?  (and not freezing) then short of replacement, reverse blowing of the pipes is your best bet. 

How?  Well, you're going to need a source of water, and you're going to need to shut off the water to and from your bathroom.    At least, the cold parts. 

A cooperative neighbor can simplify this:  hook up a good quality garden hose to his/her outside spigot.  Close the water to *your* whole house.    Now, you're going to have to create both an inlet and an outlet.   

Knowledge of how your plumbing is laid out helps, but you can do the "whole thing" if you must.

With the water off at your meter, open one or more outside water spigots.... Or the one in your basement will do.

Now, disconnect the line from your cold supply to your bathroom sink faucet.   You're going to need an adapter, here, but you want to connect the garden hose from your neighbor's outside spigot directly to the cold supply under you bathroom sink.  Note: *not* to the sink itself, that remains unhooked.  To the supply coming out of the wall:  that is, garden hose from neighbor's house directly to the cold supply coming out of the wall/floor.

Make certain the basement drain is open (or one or more outside spigot(s) is(are) open). 

Turn on the neighbor's spigot, letting cold water back-flow down your cold water supply and out the open drain(s).

You may need to turn on the hose, wait, turn it off....and repeat this several times.  Try to turn it on as sharply as you are able.

There are some adapter fittings in any well-stocked plumbing house/home improvement.  You'll want a brass female hose-fitting (1" garden hose type) and 1/2 FIP on the other end.   Male is easier, but female will work, with a short close 1/2" pipe nipple.  90% of bathroom fixtures use 1/2" at the base of the faucet.  The connection to the (hopefully) undersink valve varies, but modern houses with copper are typically 3/8" compression fittings.   Use the hose that comes from that, that would have gone to the faucet, but put the adapter(s) onto it instead.  Then screw in the garden hose. 


............

Basement?  You have a basement?   Is your basement full, or only partial?  Is your bathroom over the basement, or is it over somewhere else, like a solid slab?

[Sibling Lambicus the Toluous]

Well, that's certainly weird.

My first knee-jerk response is to assume that pipes have frozen in or near your bathroom. 

Is your house a slab or do you have a crawl space?

It's got a full basement, but the bathroom in question is on the second floor.  The kitchen is directly below, and everything's fine there.

If the latter, your foundation vent near your bathroom may be open, allowing freezing air under that portion of your house, and this could account for all your symptoms.  Draining everything would not un-freeze things, either.  Only closing the vent, and letting the pipes thaw will.   (if, indeed freezing is the issue)

Hmm.  That makes me think: maybe the insulation's been disturbed in the attic and cold air has gotten into an interior wall.  That might explain what's going on.

I haven't noticed any unusually cold walls, but then, I don't usually go rubbing up against them as a matter of course.

A builder in Canada would know better than to put pipes in an outside wall, wouldn't he?

One symptom you can verify, is the floor in your bathroom unusually cold?  (i.e. colder than elsewhere in your house).   Try walking around the perimeter of your house, and look for tiny "windows" or openings to the crawlspace.  Covering these in the winter is a good idea, and a simple sheet of 1" thick styrofoam works wonders.   But any material that covers the hole should work.

There are no holes that lead to the space... at least no man-made holes, and I hope I would've noticed if bats had pried the siding away or something like that.

Edit:  you said basement?   Hmmm....let me think about that...

No... the bathroom's on the second floor.  I just used the basement tap to try to drain the pipes.

If you really think it's blockage?  (and not freezing) then short of replacement, reverse blowing of the pipes is your best bet. 

I really don't know.  Everything seems to be behaving like the pipe has frozen, but I just don't see any way how that would be physically possible.

I'll keep in mind what you said about blowing the pipes, but it might not be practical; it would probably take several hundred feet of hose to stretch from my next door neighbor's outside spigot to the upstairs bathroom.

Basement?  You have a basement?   Is your basement full, or only partial?  Is your bathroom over the basement, or is it over somewhere else, like a solid slab?

The bathroom's on the second floor at one corner of the house.  It's immediately over top of the kitchen, which is over top of the rec room in the basement.

[beagle]

Not too familiar with North American plumbing practice, but like MB and Bob I'd go with the frozen theory, in which case the trouble will come when it thaws.

Otherwise is it possible that the bathroom water is coming off a loft tank unlike the rest of the house, and that the float valve has either stuck or frozen in the up position?

Only other things I can think off are blockage (e.g scale build up), airlock, or a faulty valve. The first I doubt would be so sudden for scale, not sure how the air would get in for the second, and (if it's like here) there's usually only a gate valve on the way down from the loft and they usually only go wrong when you shut or open them.

The low flow on the shower hot might be the thermostat compensating for having no cold feed to mix with the hot feed, depending on how it mixes before you see it.

edit

I really don't know.  Everything seems to be behaving like the pipe has frozen, but I just don't see any way how that would be physically possible.

Even with good insulation a pipe with static water in a region consistently below zero will eventually freeze of course. Have you been away? If the pipes in the roof space feed into the bathroom then up there is most likely where the problem is IMHO. Probably at least a few feet away from where they drop into the house, since copper will conduct heat from the house a short distance up.

Maybe Canadian builders are smarter than to put pipes in the roof space in such a climate though...

[The Meromorph]

Look in your roof space over the bathroom to see if there are pipes or a 'header tank' there.
If there are, then see if there are two pipes going to the bathroom or only one.
If there are two, turn on your bathroom hot water until it runs hot, then shut it off, and feel the pipes in the roof space. The hot one will obviously be the hot water. the other (or the only) pipe will be the cold water.
Tap along the length of the cold pipe with a wrench or something metal and solid to find where the sound changes from 'clang' to 'thud'. That's where the blockage is.

Edit: Some plumbers are as dumb as a bag of wet hair. I have seen more than one case where plumbers have cut through and removed a section of a floor joist in order run a pipe in a route convenient for them... (usually discovered while trying to fix a sagging floor) 

[Bob in a quantum-state-of-faith]

Okay, we've clarified a few points.

A few more questions, I promise.

Is the sink freestanding, or is it a vanity/cabnent?  That is, is the sink mounted on a box or similar built-in, that encloses it's pipes, or is the sink open to the "winds" and mounted directly to the wall?

Is the sink on an outside wall, or on a wall immediately adjacent to an outside wall?   (i.e. 90 degrees from an outside wall)

As others have correctly asked, are there water pipes in the attic?

And I just had another thought that might be the root-cause.

*all* modern plumbing since, what, the 60's at least, have vent pipes through the roof for the waste plumbing lines.   Many combine these various pipes into a single or a few runs, but older houses have separate runs for each and every drain in the house.

A vent pipe is basically a waste pipe, connected to the waste plumbing, and goes all the way up, through the roof, and is never capped--open to the elements.  (and cold air, unfortunately)

If, your sink has it's own vent stack, or if it's closely tied to the toilet's vent stack, the stack may pass up the wall next to the incoming water pipes-- not uncommon, and nothing wrong with that, either.  Well, mostly nothing.

If your vent stack is large diameter, and if it's the toilet's one it will be at least 4" in diameter (roughly 10 cm) .  This can allow quite a bit of cold air infiltration.  If the pipe is made of cast iron (many are) then it's even worse.  If the water supply pipes are in the same cavity as the vent stack, *and* if when the plumber installed these when the house was built, he likely removed or reduced any insulation in that cavity....I see this all the time, actually.  :grrr:  (too lazy to fix it right...)

In any case, the vent stack *could* be the source of the cold air, and what caused the pipes to freeze solid. 

Unfortunately, short of Superman's x-ray vision, I cannot think of any way to "see" the location of these without tearing out wallboard.   But, if your pipe's frozen, and burst?  You're going to have to do this anyway..... but wait!  Not yet! 

Hmmmm.....let me think.  One way to check on things, is to climb up on the roof, directly over your bathroom (I  know!  2 stories!  Yuck!) and look for a vent stack on the same wall that the sink is attached to.  If the stack is directly or just beside the sink, that *may* be the cause.

Fix?  The only thing I can think of is, attaching a hot-water safe hose to a hot water tap, turning on the tap, and dumping water down that vent stack to see if it un-freezes things.  It won't hurt anything: the stack leads directly to your drain pipes (that's why it doesn't need a cap, rain just goes down the drain--literally).   The worst is that you'll waste some hot water (and if you *don't* fall off your roof!  CAREFUL!)

If, after running 1/2 hour or so of hot water down the stack does not un-clog your pipes, then it's *not* the stack.   If it does?  Your freeze was in the wall, somewhere behind the sink, likely below the level of the sink itself, nearer the floor.   It depends on how your pipes were run.

If your pipes were run between floors, then up the wall to the sink, then your clog is somewhere in the wall, or beneath the bathroom floor.  This is a very common way to run plumbing, unfortunately.   If your pipes run up to the attic space, and down the wall to the sink?  Unlikely, but possible...then your clog may be higher up, and actually in the attic as the others suggested.

First, I'd look in the attic space-- easier to get to, and you can reconnoiter the vent stack while you're up there.   Look for a pipe going straight up through the roof.  Roughly 4" (10 cm) in diameter.  It will either be cast iron (black) or it will be plastic (usually white, but maybe black, blue or even grey).   Your house is too new for it to be pottery....and that's GOOD.

While up there, feel the vent stack, and look for ice built up around it's outside-- this may be a clue the stack is the source of your cold.

If you see smaller copper pipes nearby, that appear to "dive" into the attic floor, then your plumbing's in the attic space.  Use the excellent advice given by others above, to check if either one is frozen.   It may be frozen near the stack, for reasons I've outlined.

If you decide to climb on the roof?  BE SUPER, SUPER CAREFUL!!!!!!! 

NO PLUMBING IS WORTH A BROKEN LEG!  Seriously! 

If you don't want to do that? It may be worth calling in a pro....they have insurance for broken limbs!   

[Sibling Lambicus the Toluous]

I think I've figured out what's going on: it looks like the builders did put the water pipes to the upstairs bathroom on an outside wall.  The main floor walls didn't line up with the upstairs ones like I thought, so there isn't an interior wall passage to use for the riser.  However, there's a boxed-in protrusion in the kitchen, right on the corner of two outside walls that's immediately under the tub.  I'm fairly certain that's where they ran the pipes.

It's been crazy cold and windy here for the past few days, and that corner's the spot of the house that's most exposed to weather.

On a hunch, I cranked the thermostat way up yesterday evening, and by morning I was getting a dribble from the cold water tap at the tub.  Hopefully that's all it needs; if not, I'll probably end up hacking into the kitchen drywall to install an electric pipe heater.

In case that's not it, here are the answers to your questions:

Okay, we've clarified a few points.

A few more questions, I promise.

Is the sink freestanding, or is it a vanity/cabnent?  That is, is the sink mounted on a box or similar built-in, that encloses it's pipes, or is the sink open to the "winds" and mounted directly to the wall?

Is the sink on an outside wall, or on a wall immediately adjacent to an outside wall?   (i.e. 90 degrees from an outside wall)

[/quote]
It's mounted in a vanity on an outside wall.  The tub sits in the corner of two outside walls, though the tap for it is on an interior wall shared with the shower.  The toilet's at the opposite corner of the bathroom from the tub on two inside walls.

As others have correctly asked, are there water pipes in the attic?

I'm fairly certain there aren't.  The attic's designed to be a cold (i.e. below-freezing) space.

And I just had another thought that might be the root-cause.

*all* modern plumbing since, what, the 60's at least, have vent pipes through the roof for the waste plumbing lines.   Many combine these various pipes into a single or a few runs, but older houses have separate runs for each and every drain in the house.

A vent pipe is basically a waste pipe, connected to the waste plumbing, and goes all the way up, through the roof, and is never capped--open to the elements.  (and cold air, unfortunately)

If, your sink has it's own vent stack, or if it's closely tied to the toilet's vent stack, the stack may pass up the wall next to the incoming water pipes-- not uncommon, and nothing wrong with that, either.  Well, mostly nothing.

If your vent stack is large diameter, and if it's the toilet's one it will be at least 4" in diameter (roughly 10 cm) .  This can allow quite a bit of cold air infiltration.  If the pipe is made of cast iron (many are) then it's even worse.  If the water supply pipes are in the same cavity as the vent stack, *and* if when the plumber installed these when the house was built, he likely removed or reduced any insulation in that cavity....I see this all the time, actually.  :grrr:  (too lazy to fix it right...)

In any case, the vent stack *could* be the source of the cold air, and what caused the pipes to freeze solid. 

Unfortunately, short of Superman's x-ray vision, I cannot think of any way to "see" the location of these without tearing out wallboard.   But, if your pipe's frozen, and burst?  You're going to have to do this anyway..... but wait!  Not yet! 

Hmmmm.....let me think.  One way to check on things, is to climb up on the roof, directly over your bathroom (I  know!  2 stories!  Yuck!) and look for a vent stack on the same wall that the sink is attached to.  If the stack is directly or just beside the sink, that *may* be the cause.

Good thought, but my vent stack is on the opposite side of the house.  We've got two bathrooms upstairs; the vent is next to the other one, which is fine.  The frozen-up bathroom is as far away as you can get from the vent stack and still be in the house.

If your pipes were run between floors, then up the wall to the sink, then your clog is somewhere in the wall, or beneath the bathroom floor.  This is a very common way to run plumbing, unfortunately.

At this point, I think this is the most likely explanation.  There's a drywall box built into my kitchen wall that runs up the wall from floor to ceiling, then across to approximately where my bathroom sink is above.  I hadn't thought of that before because it looks kinda like an architectural feature: it looks like an extension of the drywall work above the kitchen cabinets.  In retrospect, though, it's quite possible that there's plumbing behind it.

[The Meromorph]

A possible minimal solution might be to install a grill at the top and bottom of that chase, to allow warm air to percolate through it and keep the pipes warm. (Might need to block off the chase top and bottom with fiberglass insulation...)

[Bob in a quantum-state-of-faith]

Grill is a good idea.

I was going to suggest opening a smallish hole near the floor, and insert a cheap hair dryer, set on it's lowest heat setting, and let it run....

No worries that you'll start a fire, because if the hair dryer gets too hot, it will simply quit working (there's  a thermal fuse in there).  But, I'd stick around the room, just in case.  Feel the walls from time to time to see if they are warming up, etc.

But the two grilles is a good temp fix.

Once you get the water running, open the taps and leave them until it flows full.  The running water is warmer than freezing, and ought to thaw out the pipes.  Once that's done, leave it dripping on the coldest days...

[Sibling Lambicus the Toluous]

Bob, I think great minds think alike - I just came inbto say that I fixed the problem and saw your post about the hair dryer. I found the cold water pipe in the basement ceiling as close as I could get to the riser and blasted it with a hair dryer for about ten minutes.  Thermal conductivity was my friend; that was all it took to get everything flowing again.

I'm glad it's working again. Thanks, all.

I'm annoyed with whoever designed my plumbing layout, though - the cold water pipe goes from the tee to the outside tap (i.e. a big thermal bridge) and then up a riser in the outside corner of the house most exposed to the wind (i.e. another thermal bridge). Arrrgh. I'm surprised this is the first time we've had it freeze.

[Griffin NoName]

Glad you are sorted Lambi.

Been following this with bated breath.

As you will have noted, I have a penchant for plumbing issues.

My makeshift toilet flush is still working and although visitors find it a mite puzzling I am still holding off a more thorough resolution.

The old hair dryer trick was always handy for de-icing the fridge, but it was rather slow, and I am grateful for the auto defrost. It sounds like "design" might be an over-statement for your plumbing layout.

[Bob in a quantum-state-of-faith]

Bob, I think great minds think alike - I just came inbto say that I fixed the problem and saw your post about the hair dryer. I found the cold water pipe in the basement ceiling as close as I could get to the riser and blasted it with a hair dryer for about ten minutes.  Thermal conductivity was my friend; that was all it took to get everything flowing again.

I'm glad it's working again. Thanks, all.

I'm annoyed with whoever designed my plumbing layout, though - the cold water pipe goes from the tee to the outside tap (i.e. a big thermal bridge) and then up a riser in the outside corner of the house most exposed to the wind (i.e. another thermal bridge). Arrrgh. I'm surprised this is the first time we've had it freeze.

Happy you got it sorted, finally.

If you were able to thaw it at that bend in the basement, I'd suggest over-wrapping a short heat-tape, then covering that with insulation.  It may not fix it, but it can't hurt: the worst you'll get is occasionally warm-ish water from the cold tap...

A more permanent fix, is to put additional insulation and siding on the *outside* of that wall, up the coldest side of your house.  Companies do this all the time, and you'll find it saves you money, too.  If you can't match the existing house covering, go for a deliberate contrast, just like you *intended* that wall to be different, as an accent.   

Or, if your budget allows, re-cover the whole house with additional insulation.  It *will* pay for itself over several winters.  And your comfort factor goes up, too.

If you're going to say, obviously.... 


Edit:  by heat-tape, I mean one of those electrical thingies that you plug in, and wrap your pipes with.  They come as short as 12" long, just the ticket for a short section of exposed pipe...

[Sibling DavidH]

Only now it's so cold did the icicles alert me to a drip from the overflow to the loft tank.  Normally a job like that could wait till another day, but I could see the overflow spout was already about a third blocked with ice.  So up the loft ladder I went, took the ballcock off, stripped it out and replaced the diabolically bad rubber.  Reassembling it, I lost the nozzle.  It just fell out.  It's a white thing, quite big, but it had disappeared from human ken.

So off into town.  You can't buy just a nozzle, they said, you have to have a whole new ballcock.  Only £5.97, but it's the principle of the thing.  GRRRRR!   

By jove, I feel better for that rant. 

[Griffin NoName]

Agreed ! It infuriates me not to be able to buy parts. Had similar furies with my toilet cystern (all noted here somewhere at the time).

Glad to see this thread resurrected. I always thought it an important thread !