What Happens When a Pipe Freezes and Bursts?

Water expands when it freezes into ice, unlike most substances. This expansion exerts tremendous pressure on the interior walls of the pipe. If the pressure becomes too high and there is no room for the ice to expand, the pipe material can fail. Metal pipes can rupture, while plastic pipes often split along a seam or develop a crack that opens when thawed.

The burst typically occurs at the point of greatest weakness or where the ice blockage has formed. This is often at an elbow joint, a section with existing corrosion, or a pipe run in an uninsulated exterior wall. The initial freeze may not cause the burst, but the repeated expansion and contraction from freezing cycles can fatigue the metal or plastic over time.

Water from a burst pipe does not stay on the surface. It wicks into porous materials like wood, drywall, and carpet padding. This trapped moisture creates an ideal environment for mold growth, which can start in as little as 24 to 48 hours. Mold can damage materials further and cause health issues for occupants.

Effective drying requires more than fans and dehumidifiers you might have at home. It involves specialized equipment to monitor moisture levels deep inside walls and subfloors. Without professional-grade drying, hidden dampness persists, leading to warping, swelling, and that musty odor long after the visible water is gone. This is why many homeowners contact local water damage pros for thorough mitigation.

• Hidden moisture in wall cavities and under flooring.
• Warped hardwood floors or swollen laminate planks.
• Sagging, stained, or crumbling drywall and ceilings.
• Mildew and mold growth on surfaces and in insulation.
• Damage to personal belongings like furniture and cabinets.
• Potential for foul odors from decaying wet materials.

Prevention focuses on keeping pipes warm. Insulate pipes in unheated areas like basements, attics, and crawl spaces. Seal cracks and openings in exterior walls where cold air can reach pipes. During extreme cold, let a trickle of water run from faucets supplied by vulnerable pipes. Keep cabinet doors open under sinks to allow warm room air to circulate.

Know the location of your main water shutoff valve and how to use it. If you plan to be away during cold weather, consider draining your water system or having a neighbor check your home. In a humid continental climate with cold winters and hot humid summers, these precautions are wise. If you live in Staten Island, keep your shutoff valve location written down in an easy-to-find place.