Did you know that water damage from frozen pipes that burst can be a major problem for homeowners in southern states, maybe even a bigger problem than in the colder north?
Home builders in the south often do not consider the threat of freezing weather and thus place water pipes in vulnerable locations. In addition, houses built on slab foundations, common in the south, frequently have water pipes running through the attic, an especially vulnerable location. In the north, by contrast, home builders know freezing is a threat, and they usually do not place water pipes in unheated portions of a building or outside of insulated areas.
Southern homeowners should be aware that pipes in attics, crawl spaces and outside walls are all subject to freezing and bursting. If these pipes don’t have insulation or heat to protect them, a strong overnight freeze can cause trouble.
Five Tips to Protect Your Pipes From Freezing
- Pipes in attics and crawl spaces should be protected with insulation or heat. Pipe insulation is available in fiberglass or foam sleeves. Home centers and hardware stores have sleeves providing 1/8 to 5/8 inches of insulation; specialty dealers have products that provide up to 2 inches of insulation. (Check the Yellow Pages under “Insulation” or “Plumbing Supplies” for sources.)
- Heating cables and tapes are effective in freeze protection. Select a heating cable with the UL label and a built-in thermostat that turns the heat on when needed (without a thermostat, the cable has to be plugged in each time and might be forgotten). Follow the manufacturer’s instructions closely. Doors on cabinets under kitchen and bathroom sinks should be left open during cold spells to allow the warmer air of the room to circulate around the pipes.
- Exterior pipes should be drained or enclosed in 2-inch fiberglass insulation sleeves.
- Pipes leading to the exterior should be shut off and drained at the start of the winter. If these exterior faucets do not have a shut-off valve inside the house, have one installed by a plumber.
- Let faucets drip slowly to keep water flowing through pipes that are vulnerable to freezing. Ice might still form in the pipes, but an open faucet allows water to escape before the pressure builds to where a pipe can burst. If the dripping stops, it may mean that ice is blocking the pipe; keep the faucet open, since the pipe still needs pressure relief.
Why Pipes Burst
Surprisingly, ice forming in a pipe does not typically cause a break where the ice blockage occurs. It’s not the radial expansion of ice against the wall of the pipe that causes the break. Rather, following a complete ice blockage in a pipe, continued freezing and expansion inside the pipe causes water pressure to increase downstream — between the ice blockage and a closed faucet at the end. It’s this increase in water pressure that leads to pipe failure. Usually the pipe bursts where little or no ice has formed. Upstream from the ice blockage the water can always retreat back towards its source, so there is no pressure build-up to cause a break. Water has to freeze for ice blockages to occur. Pipes that are adequately protected along their entire length by placement within the building’s insulation, insulation on the pipe itself, or heating, are safe.
What to Do if You Suspect a Frozen Pipe
If you open a faucet and no water comes out, don’t take any chances. Call a plumber. If a water pipe bursts, turn off the water at the main shut-off valve (usually at the water meter or where the main line enters the house); leave the faucet(s) open until repairs are completed. Don’t try to thaw a frozen pipe with an open flame; as this will damage the pipe and may even start a building fire. You might be able to thaw a pipe with a hand-held hair dryer. Slowly apply heat, starting close to the faucet end of the pipe, with the faucet open. Work toward the coldest section. Don’t use electrical appliances while standing in water; you could get electrocuted.