Why Do Pipes Freeze and Burst in Winter?

Water behaves differently from most liquids. As it cools toward freezing, it becomes denser, but once it turns to ice, it expands. That expansion pushes outward against the pipe walls. If the ice forms a solid plug, the water trapped between the plug and a closed valve has nowhere to go. The pressure climbs fast.

Pipes made of metal or rigid plastic can only take so much force. When the pressure exceeds the pipe's strength, the pipe cracks or splits. The break often happens at a joint, a bend, or a spot with a weak seam. You might not notice the crack right away because the ice keeps the water from leaking until temperatures rise.

• Water expands about nine percent when it freezes
• Ice plugs block flow and trap water behind them
• Pressure builds between the plug and a closed faucet or valve
• Cracks often appear at joints, bends, or weak seams
• Leaks usually show up after the ice thaws

Start by identifying the pipes most likely to freeze. Look for exposed pipes in unheated areas and add insulation sleeves or heat tape. Seal any gaps in walls or floors where cold air can reach the pipe. Keeping the garage door closed and opening cabinet doors during extreme cold helps warm air circulate.

Letting a faucet drip during freezing weather can prevent ice from forming. A slow trickle keeps water moving, which makes it harder for ice to build up. If you leave home for several days, set the thermostat no lower than 55 degrees Fahrenheit. You can also shut off the water supply and drain the pipes if you know a hard freeze is coming.

• Insulate exposed pipes in attics, garages, and basements
• Seal gaps and cracks where cold air enters
• Let a faucet drip slowly during freezing nights
• Keep the thermostat at 55 degrees or higher when away
• Shut off water and drain pipes before a long absence
• Open cabinet doors to let warm air reach under sinks

Once the water is off, the cleanup begins. Remove any standing water with a wet vacuum or mop. Pull up soaked carpets and padding, and move furniture off wet flooring. Discard items that soak up water and cannot be dried quickly, like cardboard boxes or mattresses. Open windows and use fans to speed up drying in the affected rooms.

Water can travel far from the original break, soaking into drywall, wood, and insulation. If you notice swelling, staining, or a musty smell, the moisture has likely spread. Local water damage pros can handle the full cleanup, including water-damaged flooring removal and drywall repair. They also check for hidden moisture so mold does not take hold after you think the job is done.