We recently did remodeling and replaced copper piping with PEX. The kitchen and master bath are both on an exterior wall. We are in cold climate and we have had 2 days of extreme cold (-10 to 3 degrees currently). When piping was replaced the walls were also insulated they weren’t previously. Both kitchen sink, water to refrigerator and master bath sink have no water flow. House is very warm, drywall underneath both are very warm yet obviously the PEX has frozen. Very baffled as I understood PeX takes longer to freeze than copper. My neighbor across street with no insulation, exterior wall sink, very cold under cabinet yet still has running water. Very confused! Any thoughts on how to defrost? We have 3 more days of this extreme weather and then gets into the 30’s.
Depending on where the pipes are in the wall assembly, the insulation will also prevent the heat from reaching the pipes. When you have cold weather keep these taps dripping to prevent a future freeze or move the pipes to non-exterior walls.
Keep the cabinet doors under the sink open and heat the room as much as possible to allow the heat to move to the frozen area. Getting a ceramic heater that you could point at the exterior walls you suspect have the leak could help. Keep the taps slightly open so the water can move when it expands.