Winterizing hose bibbs protects pipes

Inspector's Eye

Several methods help cut risk of freezing water

January 06, 2002|By Dean Uhler

About six years ago, during a hard freeze with snow on the ground, I heard a sound like paper tearing, but louder, beyond my rear fence. It came from the direction of my neighbors' front porch.

I crunched through the snow, stepped over the fence and followed the sound. A stream of water from under my neighbor's porch was tearing at the icy crust on the snow, making the racket. An old galvanized steel supply pipe under the porch had frozen and finally burst. The elderly ladies in the house hadn't heard a thing but took me at my word and let me into their basement to close the cutoff valve on the damaged pipe.

Theirs probably wasn't the only burst pipe that night, and others probably weren't as harmless. Most frozen pipes occur inside exterior walls of houses. If a pipe bursts there, water gushes into - and out of - the wall, often flooding the adjoining room or the basement below.

Almost everyone knows why frozen pipes burst. It's because water expands when it freezes. Trapped inside a pipe, the ice generates tremendous pressure. The pressure splits the wall of the pipe or forces a joint apart.

Any water pipe located inside an exterior wall is at risk of freezing and bursting. Pipes in those walls are chilled both by heat loss through the exterior surface of the wall and by drafts of outside air into the wall cavity.

Supply pipes to outside hose bibbs have the greatest risk because they lose heat in one additional way. In those pipes, heat is conducted directly through the metal hose bibb, away from the pipe and into the frigid outside air. If the pipe loses heat faster than it is reheated by warmth from inside the house, its temperature drops toward freezing.

To prevent frozen pipes, a rule of thumb is to winterize outside hose bibbs before Halloween and leave them that way until Easter. The procedure is simple.

First, locate and close the inside cutoff valve on the supply pipe to the outside hose bibb. Second, open the outside hose bibb. Third, return to the cutoff valve and open the knurled bleeder cap on the side of the valve body, drain the valve and re-close the bleeder.

If you can't locate an inside cutoff valve, an effective alternative is to insulate the outside hose bibb. A cover you can buy is made of rigid foam insulation and hooks to the knob on the hose bibb to keep it snug with the wall. Look for it at hardware stores.

Another venerable, if slightly wasteful, technique is to let water trickle slowly from an interior or exterior plumbing fixture to protect the supply pipe to it from temporary temperature dips.

There is one valve type that is relatively immune to freezing and does not need its water supply shut off for winter. It's the so-called frostproof or freezeproof hose bibb. These bibbs have long valves that extend a foot or more through the wall, so that the valve and the supply pipe connected to it are effectively on the inside of the house, while the hose bibb is on the outside. When the hose bibb is closed, water within the valve and hose bibb automatically drains out the threaded hose bibb outlet.

As a result, there is no water left in the parts that can get freezing cold. The only precaution required is to remove the hose from the bibb.

Inspector's Eye

Dean Uhler has been a home inspector for more than 12 years and is president of Baltimore-based Boswell Building Surveys Inc. Uhler is a member of the American Society of Home Inspectors (ASHI) and is the treasurer of the Greater Baltimore Chapter of ASHI.

Questions, with name, address and daytime telephone number, about homes and home inspections can be faxed to 410-783-2517, e-mailed to or mailed to Inspector's Eye, Second Floor, 501 N. Calvert St., Baltimore, Md. 21278-0001.

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