Q: What could cause a PVC drain pipe to burst or snap?
A: Several things can make a PVC drain fail suddenly:
- Freezing water: If the basement isn’t heated, standing water can freeze, expand, and split the pipe.
- Improper support: Long horizontal runs without hangers can sag, placing pressure on joints.
- Thermal expansion: Hot water from sinks or dishwashers can cause expansion that weakens glued joints over time.
- Vibration: A furnace or sump pump nearby can cause vibration that slowly cracks the joint.
- Faulty glue or age: PVC cement loses strength after decades, especially if the original installer used too little primer or cheap glue.
Q: Can I fix this myself, or do I need a plumber?
A: Many homeowners can repair a simple break with basic tools. Once you remove damaged drywall, inspect the break. If it’s a clean separation, cut back to solid pipe on both sides and reconnect using new PVC fittings and heavy-duty PVC cement and primer. If the pipe broke near a hub or main stack, or if it’s cast iron transitioning to PVC, calling a plumber is the safer choice.
Q: What materials do I need for a temporary repair?
A: For most drain repairs, you’ll need:
- PVC pipe of the same diameter (usually 1½” or 2″)
- Slip couplings or no-hub (rubber) couplings
- PVC primer and solvent cement
- A hacksaw or pipe cutter
- Rags and a marker for clean, dry connections
Make sure to measure twice and dry-fit all parts before applying glue. Once the cement sets, it can’t be undone.
Q: What should I do before starting repairs?
A: Turn off the water to the affected line and drain any remaining water from the sink or dishwasher above. Remove all soaked drywall and insulation — these materials trap moisture and lead to mold. Use a fan or dehumidifier to dry the area completely before you glue anything new in place.
Q: How can I prevent this from happening again?
A: Support all horizontal runs with proper hangers, insulate exposed basement pipes, and check joints annually for signs of stress or moisture. A small inspection once a year can save you from a major basement flood later.
I’m Chris Mayer, writing for Plumbing 101.