Signs a sink cabinet is at risk

  • The sink is on an exterior wall, especially under a window or on the north or west side.
  • You can feel a draft at the back of the cabinet where pipes come through the wall.
  • The faucet has run slowly on cold mornings before.
  • The cabinet back panel is missing or has large holes cut around the pipes.
  • There is a bay or garden window above the sink that extends beyond the main wall.
  • The cabinet is usually packed full, which blocks warm air from reaching the back.

Why a cabinet behaves differently from the room

The air in a kitchen may be at the thermostat setting, but the inside of a closed sink base is not. Its back panel sits against an outside wall, often with an opening where plumbers brought the supply and drain lines through. If the insulation behind that wall was disturbed during construction, or if the hole in the drywall is larger than the pipes, outdoor cold can reach the lines almost directly.

Parker winds make it worse. A west or north wind pushes cold air through small gaps in siding and sheathing, and a closed cabinet holds that cold against the pipes. Bay windows and garden windows above a sink add another weak point, since the floor of the bay is often thinner and less insulated than the wall around it.

When the line freezes it usually does so in the few inches between the wall and the shutoff valve, which means a split can leak into the cabinet floor, behind the dishwasher, or down into the basement ceiling below.

Habits for cold nights

  1. Open the doors

    Leave cabinet doors open overnight when temperatures are forecast to drop into the single digits or below zero.

  2. Clear the back

    Move cleaning supplies forward so warm air reaches the wall. Keep any chemicals out of reach of children while doors are open.

  3. Let it drip

    A thin stream from both hot and cold keeps water moving. A single-handle faucet can be set in the middle.

  4. Do not block heat registers

    Make sure a kick-space or floor register near the sink is open and not covered by a rug.

When a habit is not enough

  • IfThe sink still freezes with doors open and a dripThenAsk a plumber about sealing and insulating the wall penetration, or moving supply lines toward the interior side of the cabinet.
  • IfThere is a large, open hole behind the cabinetThenHave it sealed with material appropriate for the location, leaving the pipes accessible.
  • IfThe sink sits in a bay or garden windowThenAsk whether the bay floor and walls can be insulated from inside or below.
  • IfWater is under the sink nowThenClose the sink's shutoff valves or the main, and check the cabinet floor and the ceiling below for spread.

General information for Parker, not a quote or professional advice. In an emergency, call 911.