Rim joists
The band where the house frame meets the foundation is the coldest framed cavity in the home, and supply lines routed through it sit inches from outside air. Uninsulated rim joists are the single most common freeze point we see.
Winter Guide | Minnesota Water Damage Resource Center
Frozen Pipe Prevention for Minnesota Homes
Frozen pipes are the most predictable water loss in Minnesota, and the most preventable. They fail in the same places, during the same arctic stretches, in the same kinds of homes, year after year. A pipe does not need to be in an unheated space to freeze. It only needs to sit in a pocket the furnace cannot reach while the temperature outside stays below zero for a few days.
This guide covers where pipes freeze first, the weekend fixes that protect them, and what to do in the first minutes after a freeze or a burst. Most of the prevention here costs less than a tank of gas and takes an afternoon in October.
Where Pipes Freeze First
When our crews trace a burst pipe back to its source, it is almost always one of these four locations. If your home has any of them, that is where prevention starts.
Garage-adjacent walls
Laundry rooms, half baths, and kitchen runs that share a wall with an unheated garage lose heat through that wall all winter. A garage door left open during a cold snap can freeze those lines in a single night.
Exterior wall runs
Kitchen and bathroom supply lines routed through outside walls sit on the cold side of the insulation in many older Twin Cities homes. The cabinet under the sink blocks the room's heat from reaching them.
Knee walls, additions, and cabins
Story-and-a-half knee-wall attics, rooms built over crawl spaces, additions with shallow plumbing runs, and seasonal cabins all share the same weakness: plumbing that the original heating plan never accounted for.
The Prevention That Works
Five measures, in order of permanence. The first two are weekend projects; the rest are habits for the cold stretches.
Insulate the vulnerable runs
Foam pipe sleeves on every exposed line in the rim joist, garage wall, and crawl space, plus rigid foam or spray foam in the rim joist cavities themselves. Insulating the cavity matters as much as insulating the pipe, because the goal is keeping heated air on the pipe's side of the wall. The full room-by-room sequence is in our winter home protection checklist.
Use heat tape where insulation is not enough
For runs that cannot be rerouted or fully insulated, self-regulating heat cable rated for potable supply lines holds them above freezing. Buy listed products, follow the spacing on the label, and plug into a GFCI outlet. Heat tape is a targeted tool for problem runs, not a substitute for insulation, and the same logic applies to rooflines, which we cover in what causes ice dams.
Open cabinets and drip faucets during arctic stretches
When forecasts hold below zero for more than a day, open the cabinet doors under sinks on exterior walls so room heat reaches the plumbing, and let the farthest faucet on each vulnerable run drip, both hot and cold sides. Moving water resists freezing, and the drip relieves the pressure that turns an ice blockage into a split pipe.
Know your shutoff before you need it
The main shutoff is usually on the basement wall facing the street, near the water meter. Find it now, make sure it turns, and make sure everyone in the house can operate it. A burst pipe releases water until someone closes that valve, and hunting for it while water runs is how a one-room loss becomes a whole-floor loss.
Never leave the house unmonitored
For winter travel: keep the thermostat no lower than 55 degrees, have someone check the house every few days, and consider a wifi temperature or leak sensor that alerts your phone. For longer absences, shutting off the main and draining the lines removes the risk entirely. Many insurance policies expect reasonable heat maintenance in an occupied home, so the travel protocol protects the claim as well as the house.
If a Pipe Freezes, and If It Bursts
A frozen pipe announces itself as a faucet that slows to a trickle or stops during a cold snap. Leave that faucet open, then warm the suspect section gradually: a hair dryer, a heating pad, towels soaked in warm water, or a space heater aimed at the cabinet from a safe distance. Work from the faucet back toward the frozen section so melting ice has somewhere to go. Never use a torch, open flame, or any device with an exposed heating element on a pipe. Torches turn frozen pipes into house fires every Minnesota winter, and superheating one section can flash the water to steam and burst the line you were trying to save.
If the pipe has already split, the freeze itself may hide it. A frozen burst often stays quiet until the thaw, which is why homes flood on the warm day after the cold snap. The moment you find running water or discover a split line, close the main shutoff first, then follow the first hour protocol: safety, documentation, your insurance carrier, and a certified drying team, in that order.
Frozen Pipe Questions We Hear Most
At what temperature do pipes freeze?
Pipes in unprotected spaces become vulnerable when outside temperatures hold around 20 degrees or lower, and risk climbs sharply during sustained stretches below zero. Wind matters as much as the number, because it drives cold air into rim joists and wall cavities that still air would leave alone.
Which faucets should I let drip?
The faucet farthest from where water enters the house on each vulnerable run, especially fixtures on exterior walls or above garages. A slow, steady drip on both the hot and cold sides is enough. The water cost of a few dripping faucets for a week is trivial next to any burst pipe loss.
Does homeowners insurance cover burst pipe damage?
Sudden and accidental water discharge from plumbing is generally covered under standard homeowner policies, though carriers expect reasonable care, such as maintaining heat in an occupied home. Coverage questions belong to your carrier and your specific policy, and our restoration FAQ explains the coverage patterns in more depth.
Dealing With a Burst Pipe Right Now?
Start with the first hour protocol, then get a certified team on site. 911 Restoration of Minneapolis responds to water emergencies across the Twin Cities metro 24 hours a day.