Preventing frozen pipes on slab

I live in a house that was built in 66, it's on a slab (no crawl space or basement), and it's all copper or galvanized pipe.

I live in Southern Virginia, and it's been freezing lately. We haven't had any problem with our pipes yet - but a neighbor did. Their interior pipes burst, but no one was living in the home at the time (it's for sale) and the heat was off. so that may have factored into it.

I'm wondering if I have to worry about my pipes freezing below the slab/under the house. There is also one copper pipe that sticks out from the foundation about 5 inches. It leads out to some buried pvc pipe to carry water to the other side of the yard. I have that shut off (no water going out to the pvc). but i'm worried that the 5 inches that is exposed just before the shut off valve is in danger.

i'm sure i'm going to get a ton of opinions on this... my girlfriend thinks letting the water trickle from a faucet in the house is a waste. she just assumes turning off the water to the house at the street.

Any thoughts on this would be great. Thanks everyone.

Reply to
RedDwarf
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Maybe, but we tend to code spec in Norfolk area to southern climes.

Unlikely here.

Huh? Dont follow, turning off the water at the street means you are toilet free until you turn it back on.

Yes, trickle the water here. Just a small tricke needed.

I live in VB. Chec your house as you may have uninsulated copper pipes in overhead areas with no insulation at all. Those are your danger points. Apt area, garage here.

Reply to
cshenk

The pipes froze because the heat was totally off. Your pipes won't freeze if you keep your house heated to a reasonable temp. No need to boost the temp or end a daytime setback (if you use one) .....heat flows from your house out through the slab on grade. Are you pipes in the slab or under the slab? Does the slab have any insulation? Where are the pipes relative tothe insulation?

If you're worried about the copper pipe that protrudes from the foundation.....put some closed cell foam insulating tubing over it. The heat that is drawn from the house by the copper pipe will keep the water from freezing in the pipe.

Of course whether things freeze will depend on how cold the weather gets & how long it stays cold.....if you get

Turning the water off at the street will not prevent freezing in your house unless you drain the water system. I am eluctant to give this advice......don't listen to your g/f on plumbing issues.

Yeah, leaving a tap running does waste water and only protects those pipes through which water is actually flowing. A dead-end circuit exposed to cold for long enough will freeze.

Wasted water is cheap compared to a burst pipe somewhere in the house.

cheers Bob

Reply to
BobK207

Thanks for the information. To clarify, the plan was to turn the h20 @ the street - then open a faucet to let whatever water in there expand if it froze. We would just do that @ night of course... I appreciate the help - I have a few ideas to work with now.

Reply to
RedDwarf

keep your heat on , if your sink is on outer wall,keep the cabinet doors open there.. its no wonder your freinds pipe froze with no heat on. that would happen in any house when its that cold.lucas

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Reply to
ds549

No. The earth is a tremendous heat sink.

On a very cold night, stick a thermometer in the ground, say six inches deep.

I'd be astonished if it read below 50°F. In fact the reason a "trickle" of water works to prevent freezing is that the technique brings warmer water from underground (i.e., 50°) into the system.

As to "wasting" water: A minimal stream will "waste" about four gallons of water per night, about the same as a low-flow shower (less than one cent). An average bath uses about 30 gallons, an old-style commode flush uses six gallons.

So, if you can avoid one flush per evening, you're ahead of the game. If you can persuade your girlfriend to forego her bath by showering instead, you can "trickle" for a week on the "savings" from one bath.

Reply to
HeyBub

Is this your first house. So one unheated house freezes, but you are heated. I think you are panicking its only just below freezing you say. House plumbing is better designed than that. Even an outside spigot where I am wont freeze in a heated basement until near or below zero. Talk to your neighbors to see what they do. Last week the high here was -5 the low -20f. My spigots are shut off inside and left open and drained outside.

Reply to
ransley

That's for sure. I lived in Houston in 1983. That year there was a Siberian Express cold front that came through and gave Houston a hard freeze on Christmas day. In Houston there is a lot of plumbing in attics. A lot of people who left town for Christmas came home and found their ceilings down from the pipes in the attics that froze and burst.

I got the word not to try to travel, because of the horrid weather and spent Christmas at home. I got up Christmas morning and found the water frozen where it came up out of the ground in front of the house, then bent to go into the wall. I got it thawed out with no problem, but I don't know what would have happened if I hadn't been there.

Bill

Reply to
BillGill

I'd be most concerned with the 5" piece of exposed pipe. From the description, it's not clear exactly what this is, but if temps are falling below freezing, I'd get it either drained if it's non- essential or protected in some fashion otherwise. The house freezing with no heat is a very different situation from a heated house. Take a look at how water is run in your house. The most vulnerable spots are those completely exposed, like that 5" piece of pipe, or an outdoor faucet that isn't freeze proof. Next would be areas where water pipes flow in outside walls, or in the slab at the very perimeter of the house, etc. Generally even in those situations, with any decent construction techniques, it would have to get very cold for those pipes to freeze. From experience here in NJ, that happens when it's in the low teens or below for an extended period. If it just dips there for a few hours overnight, it's usually not a problem.

Personally, I've never had pipes freeze in my house here in NJ, except once, when the heat went off while I was away. Even then I was very lucky, because all that happened was it caused the compression fitting by one toilet to start to leak.. Recently, it was down to 2F here and no problems.

Forget about shutting the water off at the street. That isn't required and wouldn't keep the pipes from freezing. All it would do is prevent a flood. The pipes are still full of water and can freeze and bust anyway. I had a recent reminder of this. I was experimenting making granita, which is a frozen ice dessert. I put a coffee cup with water, flavoring, etc into the freezer. It froze and cracked. Now, if freezing can crack a cup with lots of open space above it, clearly relying on open expansion space doesn't mean the ice will all expand there and you will be ok.

Reply to
trader4

.....your conceptual thinking is headed in the right direction but your fresh water plumbing system does not (will not) freeze like water in a small container in the freezer.

depending on how & where the pipe are routed..... >>>>> the plan was to turn the h20 @ the street - then open a faucet to let whatever water in there expand if it froze.

Reply to
BobK207

You'll see lots of others. Turning off the water at the street won't help really. The pipes under your slab will be fine if you are around the Norfolk roughly area. We are well into the southern zone (on the coast, not western end by the mountains!)

Can you tell me how close to the coast you are? If you are near us (VB), I can give you specifics to our area, even where to look for danger spots with our type code and where to get to right products to deal with it.

If you are along the coast, the advice of the others is *not* bad but may be overkill. It misses though on some of the common construction we have that northern houses do not do and are a danger point they won't think of. Things they will go 'oh no, they didnt build like that did they?'

Area specifics if you are coastal VA along the southern part (Williamsberg and below):

Your exterior hose outlet will need one of the styrofoam covers. It will not be constructed 'freezeproof'. Drain any garden hoses and put them in the garage.

- older houses made 1970 and earlier almost always have just one and at the front. If you have one at the back as well, it's apt to have been added and may be a better freeze proof type.

Laundry rooms are most often an adjunct off the garage and commonly piped overhead in copper from the kitchen or from the inlet to the house which is often in the garage (possibly this is your 'exposed copper pipe' you mention, real common here). If that pipe is in the garage from the slab then leads into the house and with a separate line to the laundry run free along the wall then up and over, your danger spot is the laundry room. It's a dead end you cant trickle *unless* someone later added a backyard outlet off that laundry feed (you can then trickle that here and the ice wont form up high to block it).

- Garages here are totally uninsulated. There is frequently a sort of section with a plywood 'roof' over the landry section. You will see the pipes leading down from there to the laundry. This is the most common spot for busted pipes locally. The plywood (or whatever) most likely has no insulation at all and the pipes run down an exterior uninsulated wall. The whole area is unheated.

-- If you have the above, those pipes may be so close to flush to the exterior wall, you cant get real insulation behind them. Fix is a 'pipe heater' which looks alot like an extension cord and you run it along each pipe then plug it into an outlet. Then, add rolls of insulation up behind the false 'roof' of the laundry. You may be able to get some of the thin foam sheet insualtion behind the pipes. Local HD or Lowes has that as well as the pipe heaters and styrofoam exterior outlet covers.

Your main water inlet from below ground is almost sure to be by the kitchen with the hot water heater fairly close. Bathrooms tend to be on the other side of the house (not always but often so they have an exterior window) with the pipes being either overhead in an insulated attic crawlway, or in newer construction, run through the slab. If through the slab, relax. If overhead, wrap insulation over any exposed ones, if any are exposed (mine run under the slab).

Reply to
cshenk

Thanks for the information. To clarify, the plan was to turn the h20 @ the street - then open a faucet to let whatever water in there expand if it froze. We would just do that @ night of course... I appreciate the help - I have a few ideas to work with now.

You often cannot drain all the water out of the plumbing. Any that remains can still freeze and burst the pipes, it won't expand into the empty space if it is very far away. You could blow the water out with compressed air but that is usually only done for long term winterizing. Actually loss of pressure will let the water freeze easier. Insulate the outdoor pipe and let the inner faucets trickle at night if you are concerned. During the day usage will generally keep the pipes from freezing.

Don Young

Reply to
Don Young

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